转自：https://www.jianshu.com/p/10b2323f502e

1、禁止手机睡眠

[UIApplication sharedApplication].idleTimerDisabled = YES;

2、隐藏某行cell

• (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

// 如果是你需要隐藏的那一行，返回高度为0

if(indexPath.row == YouWantToHideRow)

    return 0;

return 44;

}

// 然后再你需要隐藏cell的时候调用

[self.tableView beginUpdates];

[self.tableView endUpdates];

3、禁用button高亮

button.adjustsImageWhenHighlighted = NO;

或者在创建的时候

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

4、tableview遇到这种报错failed to obtain a cell from its dataSource

是因为你的cell被调用的早了。先循环使用了cell，后又创建cell。顺序错了

可能原因：1、xib的cell没有注册 2、内存中已经有这个cell的缓存了(也就是说通过你的cellId找到的cell并不是你想要的类型)，这时候需要改下cell的标识

5、cocoa pods报这个错误：unable to access 'https://github.com/facebook/pop.git/': Operation timed out after 0 milliseconds with 0 out of 0 bytes received

解决办法：原因可能是网络问题，网络请求超时了，只需要重试就行了

6、cocoa pods 出现ERROR: While executing gem ... (Errno::EPERM)

解决办法：

https://segmentfault.com/q/1010000002926243

7、动画切换window的根控制器

// options是动画选项

[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:0.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{

    BOOL oldState = [UIView areAnimationsEnabled];

    [UIView setAnimationsEnabled:NO];

    [UIApplication sharedApplication].keyWindow.rootViewController = [RootViewController new];

    [UIView setAnimationsEnabled:oldState];

} completion:^(BOOL finished) {

}];

8、去除数组中重复的对象

NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];

9、编译的时候遇到no such file or directory: ／users／apple／XXX

是因为编译的时候，在此路径下找不到这个文件，解决这个问题，首先是是要检查缺少的文件是不是在工程中，如果不在工程中，需要从本地拖进去，如果发现已经存在工程中了，或者拖进去还是报错，这时候需要去build phases中搜索这个文件，这时候很可能会搜出现两个相同的文件，这时候，有一个路径是正确的，删除另外一个即可。如果删除了还是不行，需要把两个都删掉，然后重新往工程里拖进这个文件即可

[图片上传失败...(image-d3f000-1528096993264)]

10、iOS8系统中，tableView最好实现下-tableView: heightForRowAtIndexPath:这个代理方法，要不然在iOS8中可能就会出现显示不全或者无法响应事件的问题

11、iOS8中实现侧滑功能的时候这个方法必须实现，要不然在iOS8中无法侧滑

// 必须写的方法，和editActionsForRowAtIndexPath配对使用，里面什么不写也行

• (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

}

12、三个通知

NSSystemTimeZoneDidChangeNotification监听修改时间界面的两个按钮状态变化

UIApplicationSignificantTimeChangeNotification 监听用户改变时间 （只要点击自动设置按钮就会调用） NSSystemClockDidChangeNotification 监听用户修改时间（时间不同才会调用）

13、SDWebImage本地缓存有时候会害人。如果之前缓存过一张图片，即使下次服务器换了这张图片，但是图片url没换，用sdwebimage下载下来的还是以前那张,所以遇到这种问题，不要先去怼服务器，清空下缓存再试就好了。

14、上线前注意：

1）、删掉代码中所有的测试代码

2）、如果后台有审核模式，提醒后台开启此模式

3）、主流程再跑一跑

4）、全局搜索waring，检查所有标记waring的地方

15、跳进app权限设置

// 跳进app设置

        if (UIApplicationOpenSettingsURLString != NULL) {

            UIApplication *application = [UIApplication sharedApplication];

            NSURL *URL = [NSURL URLWithString:UIApplicationOpenSettingsURLString];

            if ([application respondsToSelector:@selector(openURL:options:completionHandler:)]) {

                [application openURL:URL options:@{}

                   completionHandler:nil];

            } else {

                [application openURL:URL];

            }

}

16、给一个view截图

UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);

[view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *img = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

17、开发中如果要动态修改tableView的tableHeaderView或者tableFooterView的高度，需要给tableView重新设置，而不是直接更改高度。正确的做法是重新设置一下tableView.tableFooterView = 更改过高度的view。为什么？其实在iOS8以上直接改高度是没有问题的，在iOS8中出现了contentSize不准确的问题，这是解决办法。

18、注意对象为nil的时候，调用此对象分类的方法不会执行

19、collectionView的内容小于其宽高的时候是不能滚动的，设置可以滚动：

collectionView.alwaysBounceHorizontal = YES;

collectionView.alwaysBounceVertical = YES;

20、设置navigationBar上的title颜色和大小

[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]

21、颜色转图片

+ (UIImage *)cl_imageWithColor:(UIColor *)color {

CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);

UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetFillColorWithColor(context, [color CGColor]);

CGContextFillRect(context, rect);

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

22、view设置圆角

define ViewBorderRadius(View, Radius, Width, Color)\

[View.layer setCornerRadius:(Radius)];\

[View.layer setMasksToBounds:YES];\

[View.layer setBorderWidth:(Width)];\

[View.layer setBorderColor:[Color CGColor]] // view圆角

23、强／弱引用

define WeakSelf(type) __weak typeof(type) weak##type = type; // weak

define StrongSelf(type) __strong typeof(type) type = weak##type; // strong

24、由角度转换弧度

define DegreesToRadian(x) (M_PI * (x) / 180.0)

25、由弧度转换角度

define RadianToDegrees(radian) (radian*180.0)/(M_PI)

26、获取图片资源

define GetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]

27、获取temp

define PathTemp NSTemporaryDirectory()

28、获取沙盒 Document

define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]

29、获取沙盒 Cache

define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]

30、GCD代码只执行一次

define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);

31、自定义NSLog

ifdef DEBUG

define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), PRETTY_FUNCTION, LINE, ##VA_ARGS)

else

define NSLog(...)

endif

32、Font

define FontL(s) [UIFont systemFontOfSize:s weight:UIFontWeightLight]

define FontR(s) [UIFont systemFontOfSize:s weight:UIFontWeightRegular]

define FontB(s) [UIFont systemFontOfSize:s weight:UIFontWeightBold]

define FontT(s) [UIFont systemFontOfSize:s weight:UIFontWeightThin]

define Font(s) FontL(s)

33、FORMAT

define FORMAT(f, ...) [NSString stringWithFormat:f, ## VA_ARGS]

34、在主线程上运行

define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);

35、开启异步线程

define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);

36、通知

define NOTIF_ADD(n, f) [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]

define NOTIF_POST(n, o) [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]

define NOTIF_REMV() [[NSNotificationCenter defaultCenter] removeObserver:self]

37、随机颜色

• (UIColor *)RandomColor {

  NSInteger aRedValue = arc4random() % 255;

  NSInteger aGreenValue = arc4random() % 255;

  NSInteger aBlueValue = arc4random() % 255;

  UIColor *randColor = [UIColor colorWithRed:aRedValue / 255.0f green:aGreenValue / 255.0f blue:aBlueValue / 255.0f alpha:1.0f];

  return randColor;

}

38、获取window

+(UIWindow*)getWindow {

UIWindow* win = nil; //[UIApplication sharedApplication].keyWindow;

for (id item in [UIApplication sharedApplication].windows) {

    if ([item class] == [UIWindow class]) {

        if (!((UIWindow*)item).hidden) {

            win = item;

            break;

        }

    }

}

return win;

}

39、修改textField的placeholder的字体颜色、大小

[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];

[textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

40、统一收起键盘

[[[UIApplication sharedApplication] keyWindow] endEditing:YES];

41、控制屏幕旋转，在控制器中写

/** 是否支持自动转屏 */

• (BOOL)shouldAutorotate {

  return YES;

}

/** 支持哪些屏幕方向 */

• (UIInterfaceOrientationMask)supportedInterfaceOrientations {

  return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;

}

/** 默认的屏幕方向（当前ViewController必须是通过模态出来的UIViewController（模态带导航的无效）方式展现出来的，才会调用这个方法） */

• (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {

  return UIInterfaceOrientationLandscapeLeft | UIInterfaceOrientationLandscapeRight;

}

42、获取app缓存大小

• (CGFloat)getCachSize {

  NSUInteger imageCacheSize = [[SDImageCache sharedImageCache] getSize];

  //获取自定义缓存大小

  //用枚举器遍历 一个文件夹的内容

  //1.获取 文件夹枚举器

  NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

  NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:myCachePath];

  __block NSUInteger count = 0;

  //2.遍历

  for (NSString *fileName in enumerator) {

    NSString *path = [myCachePath stringByAppendingPathComponent:fileName];
  
    NSDictionary *fileDict = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];
  
    count += fileDict.fileSize;//自定义所有缓存大小
  

  }

  // 得到是字节 转化为M

  CGFloat totalSize = ((CGFloat)imageCacheSize+count)/1024/1024;

  return totalSize;

}

43、清理app缓存

• (void)handleClearView {

  //删除两部分

  //1.删除 sd 图片缓存

  //先清除内存中的图片缓存

  [[SDImageCache sharedImageCache] clearMemory];

  //清除磁盘的缓存

  [[SDImageCache sharedImageCache] clearDisk];

  //2.删除自己缓存

  NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

  [[NSFileManager defaultManager] removeItemAtPath:myCachePath error:nil];

}

44、模型转字典

static NSSet *classes;

• (NSMutableDictionary *)getParameterDictionary {

  NSMutableDictionary *dict = [NSMutableDictionary dictionary];

  Class c = self.class;

  while (c) {

    unsigned count;
  
    objc_property_t *properties = class_copyPropertyList([c class], &count);
  
    for (int i = 0; i < count; i++) {
  
        NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
  
        dict[key] = [self valueForKey:key];
  
    }
  
    free(properties);
  
    // 获得父类
  
    c = class_getSuperclass(c);
  
    if ([self isClassFromFoundation:c]) break;
  

  }

  return dict;

}

• (BOOL)isClassFromFoundation:(Class)c

{

if (c == [NSObject class] || c == [NSManagedObject class]) return YES;

__block BOOL result = NO;

[[self foundationClasses] enumerateObjectsUsingBlock:^(Class foundationClass, BOOL *stop) {

    if ([c isSubclassOfClass:foundationClass]) {

        result = YES;

        *stop = YES;

    }

}];

return result;

}

• (NSSet *)foundationClasses

{

if (classes == nil) {

    // 集合中没有NSObject，因为几乎所有的类都是继承自NSObject，具体是不是NSObject需要特殊判断

    classes = [NSSet setWithObjects:

                          [NSURL class],

                          [NSDate class],

                          [NSValue class],

                          [NSData class],

                          [NSError class],

                          [NSArray class],

                          [NSDictionary class],

                          [NSString class],

                          [NSAttributedString class], nil];

}

return classes;

}

45、交换两个方法实现

Class aClass = [self class];

    SEL originalSelector = @selector(viewWillAppear:);

    SEL swizzledSelector = @selector(xxx_viewWillAppear:);

    Method originalMethod = class_getInstanceMethod(aClass, originalSelector);

    Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector);

    BOOL didAddMethod =

        class_addMethod(aClass,

            originalSelector,

            method_getImplementation(swizzledMethod),

            method_getTypeEncoding(swizzledMethod));

    if (didAddMethod) {

        class_replaceMethod(aClass,

            swizzledSelector,

            method_getImplementation(originalMethod),

            method_getTypeEncoding(originalMethod));

    } else {

        method_exchangeImplementations(originalMethod, swizzledMethod);

}

46、打印百分号和引号

NSLog(@"%%");

NSLog(@""");

47、几个常用权限判断

if ([CLLocationManager authorizationStatus] ==kCLAuthorizationStatusDenied) {

    NSLog(@"没有定位权限");

}

AVAuthorizationStatus statusVideo = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if (statusVideo == AVAuthorizationStatusDenied) {

    NSLog(@"没有摄像头权限");

}

//是否有麦克风权限

AVAuthorizationStatus statusAudio = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];

if (statusAudio == AVAuthorizationStatusDenied) {

    NSLog(@"没有录音权限");

}

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

    if (status == PHAuthorizationStatusDenied) {

        NSLog(@"没有相册权限");

    }

}];

48、获取手机型号

• (NSString *)getDeviceInfo {

  struct utsname systemInfo;

  uname(&systemInfo);

  NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSASCIIStringEncoding];

  if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";

  if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";

  if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";

  if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";

  if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";

  if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";

  if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";

  if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";

  if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";

  if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c";

  if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c";

  if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s";

  if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s";

  if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus";

  if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6";

  if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";

  if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";

  // 日行两款手机型号均为日本独占，可能使用索尼FeliCa支付方案而不是苹果支付

  if ([platform isEqualToString:@"iPhone9,1"]) return @"国行、日版、港行iPhone 7";

  if ([platform isEqualToString:@"iPhone9,2"]) return @"港行、国行iPhone 7 Plus";

  if ([platform isEqualToString:@"iPhone9,3"]) return @"美版、台版iPhone 7";

  if ([platform isEqualToString:@"iPhone9,4"]) return @"美版、台版iPhone 7 Plus";

  if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";

  if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";

  if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";

  if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";

  if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";

  if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";

  if ([platform isEqualToString:@"iPad1,1"]) return @"iPad 1G";

  if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";

  if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";

  if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";

  if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";

  if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1G";

  if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1G";

  if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1G";

  if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";

  if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";

  if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";

  if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";

  if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";

  if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";

  if ([platform isEqualToString:@"iPad4,1"]) return @"iPad Air";

  if ([platform isEqualToString:@"iPad4,2"]) return @"iPad Air";

  if ([platform isEqualToString:@"iPad4,3"]) return @"iPad Air";

  if ([platform isEqualToString:@"iPad4,4"]) return @"iPad Mini 2G";

  if ([platform isEqualToString:@"iPad4,5"]) return @"iPad Mini 2G";

  if ([platform isEqualToString:@"iPad4,6"]) return @"iPad Mini 2G";

  if ([platform isEqualToString:@"i386"]) return @"iPhone Simulator";

  if ([platform isEqualToString:@"x86_64"]) return @"iPhone Simulator";

  return platform;

}

49、长按复制功能

• (void)viewDidLoad

{

[self.view addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(pasteBoard:)]];

}

• (void)pasteBoard:(UILongPressGestureRecognizer *)longPress {

  if (longPress.state == UIGestureRecognizerStateBegan) {

    UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
  
    pasteboard.string = @"需要复制的文本";
  

  }

}

50、cocoapods升级

在终端执行 sudo gem install -n / usr / local / bin cocoapods --pre

51、设置启动页后，依然显示之前的

删除app，手机重启，重新安装

52、判断图片类型

//通过图片Data数据第一个字节 来获取图片扩展名

• (NSString *)contentTypeForImageData:(NSData *)data

{

uint8_t c;

[data getBytes:&c length:1];

switch (c)

{

    case 0xFF:

        return @"jpeg";

    case 0x89:

        return @"png";

    case 0x47:

        return @"gif";

    case 0x49:

    case 0x4D:

        return @"tiff";

    case 0x52:

    if ([data length] < 12) {

        return nil;

    }

    NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];

    if ([testString hasPrefix:@"RIFF"]

        && [testString hasSuffix:@"WEBP"])

    {

        return @"webp";

    }

    return nil;

}

return nil;

}

53、获取手机和app信息

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];

CFShow(infoDictionary);

// app名称

NSString *app_Name = [infoDictionary objectForKey:@"CFBundleDisplayName"];

// app版本

NSString *app_Version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];

// app build版本

NSString *app_build = [infoDictionary objectForKey:@"CFBundleVersion"];

//手机序列号 

NSString* identifierNumber = [[UIDevice currentDevice] uniqueIdentifier]; 

NSLog(@"手机序列号: %@",identifierNumber); 

//手机别名： 用户定义的名称 

NSString* userPhoneName = [[UIDevice currentDevice] name]; 

NSLog(@"手机别名: %@", userPhoneName); 

//设备名称 

NSString* deviceName = [[UIDevice currentDevice] systemName]; 

NSLog(@"设备名称: %@",deviceName ); 

//手机系统版本 

NSString* phoneVersion = [[UIDevice currentDevice] systemVersion]; 

NSLog(@"手机系统版本: %@", phoneVersion); 

//手机型号 

NSString* phoneModel = [[UIDevice currentDevice] model]; 

NSLog(@"手机型号: %@",phoneModel ); 

//地方型号  （国际化区域名称） 

NSString* localPhoneModel = [[UIDevice currentDevice] localizedModel]; 

NSLog(@"国际化区域名称: %@",localPhoneModel ); 

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary]; 

// 当前应用名称 

NSString *appCurName = [infoDictionary objectForKey:@"CFBundleDisplayName"]; 

NSLog(@"当前应用名称：%@",appCurName); 

// 当前应用软件版本  比如：1.0.1 

NSString *appCurVersion = [infoDictionary objectForKey:@"CFBundleShortVersionString"]; 

NSLog(@"当前应用软件版本:%@",appCurVersion); 

// 当前应用版本号码   int类型 

NSString *appCurVersionNum = [infoDictionary objectForKey:@"CFBundleVersion"]; 

NSLog(@"当前应用版本号码：%@",appCurVersionNum);

54、获取一个类的所有属性

id LenderClass = objc_getClass("Lender");

unsigned int outCount, I;

objc_property_t *properties = class_copyPropertyList(LenderClass, &outCount);

for (i = 0; i < outCount; i++) {

objc_property_t property = properties[I];

fprintf(stdout, "%s %s\n", property_getName(property), property_getAttributes(property));

}

55、image圆角

• (UIImage *)circleImage

{

// NO代表透明

UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);

// 获得上下文

CGContextRef ctx = UIGraphicsGetCurrentContext();

// 添加一个圆

CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);

// 方形变圆形

CGContextAddEllipseInRect(ctx, rect);

// 裁剪

CGContextClip(ctx);

// 将图片画上去

[self drawInRect:rect];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

56、image拉伸

• (UIImage *)resizableImage:(NSString *)imageName

{

UIImage *image = [UIImage imageNamed:imageName];

CGFloat imageW = image.size.width;

CGFloat imageH = image.size.height;

return [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageH * 0.5, imageW * 0.5, imageH * 0.5, imageW * 0.5) resizingMode:UIImageResizingModeStretch];

}

57、JSON字符串转字典

• (NSDictionary *)parseJSONStringToNSDictionary:(NSString *)JSONString {

  NSData *JSONData = [JSONString dataUsingEncoding:NSUTF8StringEncoding];

  NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableLeaves error:nil];

  return responseJSON;

}

58、身份证号验证

• (BOOL)validateIdentityCard {

  BOOL flag;

  if (self.length <= 0) {

    flag = NO;
  
    return flag;
  

  }

  NSString *regex2 = @"^(\d{14}|\d{17})(\d|[xX])$";

  NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];

  return [identityCardPredicate evaluateWithObject:self];

}

59、获取设备mac地址

• (NSString *)macAddress {

  int mib[6];

  size_t len;

  char *buf;

  unsigned char *ptr;

  struct if_msghdr *ifm;

  struct sockaddr_dl *sdl;

  mib[0] = CTL_NET;

  mib[1] = AF_ROUTE;

  mib[2] = 0;

  mib[3] = AF_LINK;

  mib[4] = NET_RT_IFLIST;

  if((mib[5] = if_nametoindex("en0")) == 0) {

    printf("Error: if_nametoindex error\n");
  
    return NULL;
  

  }

  if(sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {

    printf("Error: sysctl, take 1\n");
  
    return NULL;
  

  }

  if((buf = malloc(len)) == NULL) {

    printf("Could not allocate memory. Rrror!\n");
  
    return NULL;
  

  }

  if(sysctl(mib, 6, buf, &len, NULL, 0) < 0) {

    printf("Error: sysctl, take 2");
  
    return NULL;
  

  }

  ifm = (struct if_msghdr *)buf;

  sdl = (struct sockaddr_dl *)(ifm + 1);

  ptr = (unsigned char *)LLADDR(sdl);

  NSString *outstring = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X",

                       *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
  

  free(buf);

  return outstring;

}

60、导入自定义字体库

1、找到你想用的字体的 ttf 格式，拖入工程

2、在工程的plist中增加一行数组，“Fonts provided by application”

3、为这个key添加一个item，value为你刚才导入的ttf文件名

4、直接使用即可：label.font = [UIFont fontWithName:@"你刚才导入的ttf文件名" size:20.0]；

61、拿到当前正在显示的控制器，不管是push进去的，还是present进去的都能拿到

• (UIViewController )getVisibleViewControllerFrom:(UIViewController)vc {

  if ([vc isKindOfClass:[UINavigationController class]]) {

    return [self getVisibleViewControllerFrom:[((UINavigationController*) vc) visibleViewController]];
  

  }else if ([vc isKindOfClass:[UITabBarController class]]){

    return [self getVisibleViewControllerFrom:[((UITabBarController*) vc) selectedViewController]];
  

  } else {

    if (vc.presentedViewController) {
  
        return [self getVisibleViewControllerFrom:vc.presentedViewController];
  
    } else {
  
        return vc;
  
    }
  

  }

}

62、runtime为一个类动态添加属性

// 动态添加属性的本质是: 让对象的某个属性与值产生关联

objc_setAssociatedObject(self, WZBPlaceholderViewKey, placeholderView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

63、获取runtime为一个类动态添加的属性

objc_getAssociatedObject(self, WZBPlaceholderViewKey);

64、KVO监听某个对象的属性

// 添加监听者

[self addObserver:self forKeyPath:property options:NSKeyValueObservingOptionNew context:nil];

// 当监听的属性值变化的时候会来到这个方法

• (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

  if ([keyPath isEqualToString:@"property"]) {

   [self textViewTextChange];
  
   } else {
  

  }

}

65、Reachability判断网络状态

NetworkStatus status = [[Reachability reachabilityForInternetConnection] currentReachabilityStatus];

if (status == NotReachable) {

    NSLog(@"当前设备无网络");

}

if (status == ReachableViaWiFi) {

    NSLog(@"当前wifi网络");

}

if (status == ReachableViaWWAN) {

    NSLog(@"当前蜂窝移动网络");

}

66、AFNetworking监听网络状态

// 监听网络状况

AFNetworkReachabilityManager *mgr = [AFNetworkReachabilityManager sharedManager];

[mgr setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {

    switch (status) {

        case AFNetworkReachabilityStatusUnknown:

            break;

        case AFNetworkReachabilityStatusNotReachable: {

            [SVProgressHUD showInfoWithStatus:@"当前设备无网络"];

        }

            break;

        case AFNetworkReachabilityStatusReachableViaWiFi:

            [SVProgressHUD showInfoWithStatus:@"当前Wi-Fi网络"];

            break;

        case AFNetworkReachabilityStatusReachableViaWWAN:

            [SVProgressHUD showInfoWithStatus:@"当前蜂窝移动网络"];

            break;

        default:

            break;

    }

}];

[mgr startMonitoring];

67、透明颜色不影响子视图透明度

[UIColor colorWithRed:<#(CGFloat)#> green:<#(CGFloat)#> blue:<#(CGFloat)#> alpha:<#(CGFloat)#>];

68、取图片某一点的颜色

if (point.x < 0 || point.y < 0) return nil;

CGImageRef imageRef = self.CGImage;

NSUInteger width = CGImageGetWidth(imageRef);

NSUInteger height = CGImageGetHeight(imageRef);

if (point.x >= width || point.y >= height) return nil;

unsigned char *rawData = malloc(height * width * 4);

if (!rawData) return nil;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

NSUInteger bytesPerPixel = 4;

NSUInteger bytesPerRow = bytesPerPixel * width;

NSUInteger bitsPerComponent = 8;

CGContextRef context = CGBitmapContextCreate(rawData,

                                             width,

                                             height,

                                             bitsPerComponent,

                                             bytesPerRow,

                                             colorSpace,

                                             kCGImageAlphaPremultipliedLast

                                             | kCGBitmapByteOrder32Big);

if (!context) {

    free(rawData);

    return nil;

}

CGColorSpaceRelease(colorSpace);

CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);

CGContextRelease(context);

int byteIndex = (bytesPerRow * point.y) + point.x * bytesPerPixel;

CGFloat red   = (rawData[byteIndex]     * 1.0) / 255.0;

CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;

CGFloat blue  = (rawData[byteIndex + 2] * 1.0) / 255.0;

CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;

UIColor *result = nil;

result = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];

free(rawData);

return result;

69、判断该图片是否有透明度通道

• (BOOL)hasAlphaChannel

{

CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);

return (alpha == kCGImageAlphaFirst ||

        alpha == kCGImageAlphaLast ||

        alpha == kCGImageAlphaPremultipliedFirst ||

        alpha == kCGImageAlphaPremultipliedLast);

}

70、获得灰度图

• (UIImage)covertToGrayImageFromImage:(UIImage)sourceImage

{

int width = sourceImage.size.width;

int height = sourceImage.size.height;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);

CGColorSpaceRelease(colorSpace);

if (context == NULL) {

    return nil;

}

CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);

CGImageRef contextRef = CGBitmapContextCreateImage(context);

UIImage *grayImage = [UIImage imageWithCGImage:contextRef];

CGContextRelease(context);

CGImageRelease(contextRef);

return grayImage;

}

71、根据bundle中的文件名读取图片

• (UIImage *)imageWithFileName:(NSString *)name {

  NSString *extension = @"png";

  NSArray *components = [name componentsSeparatedByString:@"."];

  if ([components count] >= 2) {

    NSUInteger lastIndex = components.count - 1;
  
    extension = [components objectAtIndex:lastIndex];
  
    name = [name substringToIndex:(name.length-(extension.length+1))];
  

  }

  // 如果为Retina屏幕且存在对应图片，则返回Retina图片，否则查找普通图片

  if ([UIScreen mainScreen].scale == 2.0) {

    name = [name stringByAppendingString:@"@2x"];
  
    NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];
  
    if (path != nil) {
  
        return [UIImage imageWithContentsOfFile:path];
  
    }
  

  }

  if ([UIScreen mainScreen].scale == 3.0) {

    name = [name stringByAppendingString:@"@3x"];
  
    NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];
  
    if (path != nil) {
  
        return [UIImage imageWithContentsOfFile:path];
  
    }
  

  }

  NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

  if (path) {

    return [UIImage imageWithContentsOfFile:path];
  

  }

  return nil;

}

72、合并两个图片

• (UIImage)mergeImage:(UIImage)firstImage withImage:(UIImage*)secondImage {

  CGImageRef firstImageRef = firstImage.CGImage;

  CGFloat firstWidth = CGImageGetWidth(firstImageRef);

  CGFloat firstHeight = CGImageGetHeight(firstImageRef);

  CGImageRef secondImageRef = secondImage.CGImage;

  CGFloat secondWidth = CGImageGetWidth(secondImageRef);

  CGFloat secondHeight = CGImageGetHeight(secondImageRef);

  CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));

  UIGraphicsBeginImageContext(mergedSize);

  [firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];

  [secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];

  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

  UIGraphicsEndImageContext();

  return image;

}

73、根据bundle中的图片名创建imageview

• (id)imageViewWithImageNamed:(NSString*)imageName

{

return [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];

}

74、为imageView添加倒影

CGRect frame = self.frame;

frame.origin.y += (frame.size.height + 1);

UIImageView *reflectionImageView = [[UIImageView alloc] initWithFrame:frame];

self.clipsToBounds = TRUE;

reflectionImageView.contentMode = self.contentMode;

[reflectionImageView setImage:self.image];

reflectionImageView.transform = CGAffineTransformMakeScale(1.0, -1.0);

CALayer *reflectionLayer = [reflectionImageView layer];

CAGradientLayer *gradientLayer = [CAGradientLayer layer];

gradientLayer.bounds = reflectionLayer.bounds;

gradientLayer.position = CGPointMake(reflectionLayer.bounds.size.width / 2, reflectionLayer.bounds.size.height * 0.5);

gradientLayer.colors = [NSArray arrayWithObjects:

                        (id)[[UIColor clearColor] CGColor],

                        (id)[[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.3] CGColor], nil];

gradientLayer.startPoint = CGPointMake(0.5,0.5);

gradientLayer.endPoint = CGPointMake(0.5,1.0);

reflectionLayer.mask = gradientLayer;

[self.superview addSubview:reflectionImageView];

75、画水印

// 画水印

• (void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect

{

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)

{

    UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);

}

//原图

[image drawInRect:self.bounds];

//水印图

[mark drawInRect:rect];

UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

self.image = newPic;

}

76、让label的文字内容显示在左上／右上／左下／右下／中心顶／中心底部

自定义UILabel

// 重写label的textRectForBounds方法

• (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {

  CGRect rect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];

  switch (self.textAlignmentType) {

    case WZBTextAlignmentTypeLeftTop: {
  
        rect.origin = bounds.origin;
  
    }
  
        break;
  
    case WZBTextAlignmentTypeRightTop: {
  
        rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, bounds.origin.y);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeLeftBottom: {
  
        rect.origin = CGPointMake(bounds.origin.x, CGRectGetMaxY(bounds) - rect.size.height);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeRightBottom: {
  
        rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, CGRectGetMaxY(bounds) - rect.size.height);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeTopCenter: {
  
        rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - rect.origin.y);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeBottomCenter: {
  
        rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - CGRectGetMaxY(bounds) - rect.size.height);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeLeft: {
  
        rect.origin = CGPointMake(0, rect.origin.y);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeRight: {
  
        rect.origin = CGPointMake(rect.origin.x, 0);
  
    }
  
        break;
  
    case WZBTextAlignmentTypeCenter: {
  
        rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, (CGRectGetHeight(bounds) - CGRectGetHeight(rect)) / 2);
  
    }
  
        break;
  
    default:
  
        break;
  

  }

  return rect;

}

• (void)drawTextInRect:(CGRect)rect {

  CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];

  [super drawTextInRect:textRect];

}

77、scrollView上的输入框，键盘挡住的问题

推荐用IQKeyboardManager这个框架！

手动解决如下

1、监听键盘弹出／消失的通知

2、在通知中加入代码：

NSDictionary* info = [aNotification userInfo];

CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];

CGSize kbSize =keyPadFrame.size;

CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];

CGRect aRect = self.view.bounds;

aRect.size.height -= (kbSize.height);

CGPoint origin = activeRect.origin;

origin.y -= backScrollView.contentOffset.y;

if (!CGRectContainsPoint(aRect, origin)) {

CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));

[backScrollView setContentOffset:scrollPoint animated:YES];

}

78、frame布局的cell动态高度

这种通常在你的模型中添加一个辅助属性cellHeight，在模型中重写这个属性的get方法，根据你的布局和模型中的其他属性值计算出总高度。最后在tableView：heightForRow方法中，根据indexPath找出对应的模型，返回这个高度即可。

79、AutoLayout布局的cell动态高度

// 1、设置tableView的属性

self.tableView.rowHeight = UITableViewAutomaticDimension;

self.tableView.estimatedRowHeight = 44.0; // 这个属性非0，估计cell高度

// 2、至上而下设置cell的约束，注意，上下左右最好都要顶到cell的四周

[图片上传失败...(image-f26e48-1528096993264)]

80、使用performSelector:调用函数，内存泄漏问题

当我们在开发中使用[obj performSelector:NSSelectorFromString(@"aMethod")];这类方法时可能会收到一个警告"performSelector may cause a leak because its selector is unknown".

是因为编译器不清楚这个对象能不能相应这个方法，如果不能，则是不安全的，而且编译器也不清楚该怎么处理这个方法的返回值！

使用以下代码调用即可：

if (! obj) { return; }

SEL selector = NSSelectorFromString(@"aMethod");

IMP imp = [obj methodForSelector:selector];

void (*func)(id, SEL) = (void *)imp;

func(obj, selector);

或者：

SEL selector = NSSelectorFromString(@"aMethod");

((void (*)(id, SEL))[obj methodForSelector:selector])(obj, selector);

81、一个字符串是否包含另一个字符串

// 方法1

if ([str1 containsString:str2]) {

    NSLog(@"str1包含str2");

} else {

    NSLog(@"str1不包含str2");

}

// 方法2

if ([str1 rangeOfString: str2].location == NSNotFound) {

    NSLog(@"str1不包含str2");

} else {

    NSLog(@"str1包含str2");

}

82、cell去除选中效果

cell.selectionStyle = UITableViewCellSelectionStyleNone;

83、cell点按效果

• (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

  [tableView deselectRowAtIndexPath:indexPath animated:YES];

}

84、当删除一个从xib拖出来的属性时，一定记得把xib中对应的线也删掉，不然会报类似[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key的crash

[图片上传失败...(image-f165d6-1528096993264)]

点击这个叉号删除

85、真机测试的时候报错：Could not launch "你的 App"，process launch failed: Security

因为你的app没有上线，iOS9开始，需要手动信任Xcode生成的描述文件，打开手机设置->通用->描述文件->点击你的app的描述文件->点击信任

86、真机测试的时候报错：Could not find Developer Disk Image

这是因为你的设备系统版本大于Xcode能兼容的系统版本，比如你的设备是iOS10.3，而Xcode版本是8.2（Xcode8.2最大兼容iOS10.2），就会报这个错误。解决办法就是升级Xcode！

87、UITextView没有placeholder的问题？

网上有很多此类自定义控件，也可以参考下我写的一个UITextView分类UITextView-WZB

88、移除字符串中的空格和换行

• (NSString *)removeSpaceAndNewline:(NSString *)str {

  NSString *temp = [str stringByReplacingOccurrencesOfString:@" " withString:@""];

  temp = [temp stringByReplacingOccurrencesOfString:@"\r" withString:@""];

  temp = [temp stringByReplacingOccurrencesOfString:@"\n" withString:@""];

  return temp;

}

89、判断字符串中是否有空格

• (BOOL)isBlank:(NSString *)str {

  NSRange _range = [str rangeOfString:@" "];

  if (_range.location != NSNotFound) {

    //有空格
  
    return YES;
  

  } else {

    //没有空格
  
    return NO;
  

  }

}

90、获取一个视频的第一帧图片

NSURL *url = [NSURL URLWithString:filepath];

AVURLAsset *asset1 = [[AVURLAsset alloc] initWithURL:url options:nil];

AVAssetImageGenerator *generate1 = [[AVAssetImageGenerator alloc] initWithAsset:asset1];

generate1.appliesPreferredTrackTransform = YES;

NSError *err = NULL;

CMTime time = CMTimeMake(1, 2);

CGImageRef oneRef = [generate1 copyCGImageAtTime:time actualTime:NULL error:&err];

UIImage *one = [[UIImage alloc] initWithCGImage:oneRef];

return one;

91、获取视频的时长

• (NSInteger)getVideoTimeByUrlString:(NSString *)urlString {

  NSURL *videoUrl = [NSURL URLWithString:urlString];

  AVURLAsset *avUrl = [AVURLAsset assetWithURL:videoUrl];

  CMTime time = [avUrl duration];

  int seconds = ceil(time.value/time.timescale);

  return seconds;

}

92、字符串是否为空

• (BOOL)isEqualToNil:(NSString *)str {

  return str.length <= 0 || [str isEqualToString:@""] || !str;

}

93、将app上传到App Store的时候通常会遇到这个问题

[图片上传失败...(image-d31d20-1528096993264)]

try again

很多人说这事苹果爸爸服务器问题，重复尝试几次，总会成功的！

但是经过尝试发现如果使用Application Loader上传成功率就非常高，所以还是推荐把ipa文件导出直接用Application Loader上传。

如果Application Loader也不行，需要检查下自己的网络，有时候vpn也会提高速度。

94、当tableView占不满一屏时，去除下边多余的单元格

self.tableView.tableHeaderView = [UIView new];

self.tableView.tableFooterView = [UIView new];

95、isKindOfClass和isMemberOfClass的区别

isKindOfClass可以判断某个对象是否属于某个类，或者这个类的子类。

isMemberOfClass更加精准，它只能判断这个对象类型是否为这个类(不能判断子类)

96、__block

当一个局部变量需要在block里改变时，需要在定义时加上__block修饰，具体请看官方文档http://developer.apple.com/library/ios/documentation/cocoa/Conceptual/Blocks/Articles/bxVariables.html#//apple_ref/doc/uid/TP40007502-CH6-SW6

97、-[ViewController aMethod:]: unrecognized selector sent to instance 0x7fe91e607fb0

这是一个经典错误，ViewController不能响应aMethod这个方法，错误原因可能viewController文件中没有实现aMethod这个方法

98、UITableView () failed to obtain a cell from its dataSource ()

这个错误原因是tableView的代理方法-tableView:cellForRowAtIndexPath:需要返回一个UITableViewCell,而你返回了一个nil。另外这个地方返回值不是UITableViewCell类型也会导致崩溃

99、约束如何做UIView动画？

1、把需要改的约束Constraint拖条线出来，成为属性

2、在需要动画的地方加入代码，改变此属性的constant属性

3、开始做UIView动画，动画里边调用layoutIfNeeded方法

@property (weak, nonatomic) IBOutlet NSLayoutConstraint *buttonTopConstraint;

self.buttonTopConstraint.constant = 100;

[UIView animateWithDuration:.5 animations:^{

    [self.view layoutIfNeeded];

}];

100、从NSURL中拿到链接字符串

NSString *urlString = myURL.absoluteString;

101、将tableView滚动到顶部

[tableView setContentOffset:CGPointZero animated:YES];

或者

[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];

102、如果用addTarget:action:forControlEvents:方法为一个button添加了很多点击事件，在某个时刻想一次删除怎么办？只需要调用下边这句代码

[youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents];

103、某个字体的高度

font.lineHeight;

104、删除某个view所有的子视图

[[someView subviews]

makeObjectsPerformSelector:@selector(removeFromSuperview)];

105、删除NSUserDefaults所有记录

//方法一

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];

[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

//方法二

• (void)resetDefaults {

  NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];

  NSDictionary * dict = [defs dictionaryRepresentation];

  for (id key in dict) {

      [defs removeObjectForKey:key];
  

  }

  [defs synchronize];
  

}

// 方法三

[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];

106、禁用系统滑动返回功能

• (void)viewDidAppear:(BOOL)animated

{

 [super viewDidAppear:animated];

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = self;

}

}

• (void)viewWillDisappear:(BOOL)animated {

  [super viewWillDisappear:animated];

  if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = nil;

  }

}

• (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

 return NO;

}

107、模拟器报错

[图片上传失败...(image-f07198-1528096993264)]

模拟器报错

解决办法：

打开模拟器->Simulator->Reset Content and Settings...

如果不行，就重启试试！

108、自定义cell选中背景颜色

UIView *bgColorView = [[UIView alloc] init];

bgColorView.backgroundColor = [UIColor redColor];

[cell setSelectedBackgroundView:bgColorView];

109、UILabel设置内边距

子类化UILabel，重写drawTextInRect方法

• (void)drawTextInRect:(CGRect)rect {

  // 边距，上左下右

  UIEdgeInsets insets = {0, 5, 0, 5};

  [super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];

}

110、UILabel设置文字描边

子类化UILabel，重写drawTextInRect方法

• (void)drawTextInRect:(CGRect)rect

{

CGContextRef c = UIGraphicsGetCurrentContext();

// 设置描边宽度

CGContextSetLineWidth(c, 1);

CGContextSetLineJoin(c, kCGLineJoinRound);

CGContextSetTextDrawingMode(c, kCGTextStroke);

// 描边颜色

self.textColor = [UIColor redColor];

[super drawTextInRect:rect];

// 文本颜色

self.textColor = [UIColor yellowColor];

CGContextSetTextDrawingMode(c, kCGTextFill);

[super drawTextInRect:rect];

}

111、使用模拟器截图

快捷键command + s

或者File->Save Screen Shot

112、scrollView滚动到最下边

CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height);

[scrollView setContentOffset:bottomOffset animated:YES];

113、UIView背景颜色渐变

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];

[self.view addSubview:view];

CAGradientLayer *gradient = [CAGradientLayer layer];

gradient.frame = view.bounds;

gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];

[view.layer insertSublayer:gradient atIndex:0];

114、停止UIView动画

[yourView.layer removeAllAnimations]

115、为UIView某个角添加圆角

// 左上角和右下角添加圆角

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(20, 20)];

CAShapeLayer *maskLayer = [CAShapeLayer layer];

maskLayer.frame = view.bounds;

maskLayer.path = maskPath.CGPath;

view.layer.mask = maskLayer;

116、删除Xcode Derived data缓存数据

依次点击Xcode -> Preferences -> location，然后点击 Derived data路径后到小箭头，删除这个文件夹下的数据就可以了，如图

[图片上传失败...(image-74106b-1528096993264)]

Xcode Derived data

117、将一个view放置在其兄弟视图的最上面

[parentView bringSubviewToFront:yourView]

118、将一个view放置在其兄弟视图的最下面

[parentView sendSubviewToBack:yourView]

119、让手机震动一下

倒入框架

import

AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);

或者

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

120、layoutSubviews方法什么时候调用？

1、init方法不会调用

2、addSubview方法等时候会调用

3、bounds改变的时候调用

4、scrollView滚动的时候会调用scrollView的layoutSubviews方法(所以不建议在scrollView的layoutSubviews方法中做复杂逻辑)

5、旋转设备的时候调用

6、子视图被移除的时候调用

参考请看：http://blog.logichigh.com/2011/03/16/when-does-layoutsubviews-get-called/

121、让UILabel在指定的地方换行

// 换行符为\n,在需要换行的地方加上这个符号即可，如

label.numberOfLines = 0;

label.text = @"此处\n换行";

122、摇一摇功能

1、打开摇一摇功能

[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;

2、让需要摇动的控制器成为第一响应者

[self becomeFirstResponder];

3、实现以下方法

// 开始摇动

• (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 取消摇动

• (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 摇动结束

• (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event

123、获取图片大小

CGFloat imageWidth = image.size.width;

CGFloat imageHeight = imageWidth * image.scale;

124、获取view的坐标在整个window上的位置

// v上的(0, 0)点在toView上的位置

CGPoint point = [v convertPoint:CGPointMake(0, 0) toView:[UIApplication sharedApplication].windows.lastObject];

或者

CGPoint point = [v.superview convertPoint:v.frame.origin toView:[UIApplication sharedApplication].windows.lastObject];

125、提交App Store审核程序限制

您的应用程序的未压缩大小必须小于4GB。每个Mach-O可执行文件（例如app_name.app/app_name）不能超过这些限制：

对于MinimumOSVersion小于7.0的应用程序：TEXT二进制文件中所有部分的总数最多为80 MB 。

对于MinimumOSVersion7.x到8.x的应用程序：TEXT对于二进制文件中每个体系结构片段的每个片段，最大为60 MB 。

对于MinimumOSVersion9.0或更高版本的应用程序：__TEXT二进制文件中所有部分的总数最多为500 MB 。参阅：iTunes Connect开发者指南

126、修改UISegmentedControl的字体大小

[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];

127、在非ViewController的地方弹出UIAlertController对话框

// 最好抽成一个分类

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];

//...

id rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;

if([rootViewController isKindOfClass:[UINavigationController class]])

{

rootViewController = ((UINavigationController *)rootViewController).viewControllers.firstObject;

}

if([rootViewController isKindOfClass:[UITabBarController class]])

{

rootViewController = ((UITabBarController *)rootViewController).selectedViewController;

}

[rootViewController presentViewController:alertController animated:YES completion:nil];

128、获取一个view所属的控制器

// view分类方法

• (UIViewController *)belongViewController {

  for (UIView *next = [self superview]; next; next = next.superview) {

    UIResponder* nextResponder = [next nextResponder];
  
    if ([nextResponder isKindOfClass:[UIViewController class]]) {
  
        return (UIViewController *)nextResponder;
  
    }
  

  }

  return nil;

}

129、UIImage和base64互转

// view分类方法

• (NSString *)encodeToBase64String:(UIImage *)image {

return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

}

• (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {

  NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];

  return [UIImage imageWithData:data];

}

130、UIWebView设置背景透明

[webView setBackgroundColor:[UIColor clearColor]];

[webView setOpaque:NO];

131、判断NSDate是不是今天

NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];

NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];

if([today day] == [otherDay day] &&

[today month] == [otherDay month] &&

[today year] == [otherDay year] &&

[today era] == [otherDay era]) {

// 是今天

}

132、设置tableView分割线颜色

[self.tableView setSeparatorColor:[UIColor myColor]];

133、设置屏幕方向

NSNumber *orientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationLandscapeLeft];

[[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];

[UIViewController attemptRotationToDeviceOrientation];

134、比较两个颜色是否相等

• (BOOL)isEqualToColor:(UIColor *)otherColor {

  CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();

  UIColor (^convertColorToRGBSpace)(UIColor) = ^(UIColor *color) {

    if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) == kCGColorSpaceModelMonochrome) {
  
        const CGFloat *oldComponents = CGColorGetComponents(color.CGColor);
  
        CGFloat components[4] = {oldComponents[0], oldComponents[0], oldComponents[0], oldComponents[1]};
  
        CGColorRef colorRef = CGColorCreate( colorSpaceRGB, components );
  
        UIColor *color = [UIColor colorWithCGColor:colorRef];
  
        CGColorRelease(colorRef);
  
        return color;           
  
    } else
  
        return color;
  

  };

  UIColor *selfColor = convertColorToRGBSpace(self);

  otherColor = convertColorToRGBSpace(otherColor);

  CGColorSpaceRelease(colorSpaceRGB);

  return [selfColor isEqual:otherColor];

}

135、tableViewCell分割线顶到头

• (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

  [cell setSeparatorInset:UIEdgeInsetsZero];

  [cell setLayoutMargins:UIEdgeInsetsZero];

  cell.preservesSuperviewLayoutMargins = NO;

}

• (void)viewDidLayoutSubviews {

  [self.tableView setSeparatorInset:UIEdgeInsetsZero];

  [self.tableView setLayoutMargins:UIEdgeInsetsZero];

}

136、不让控制器的view随着控制器的xib拉伸或压缩

self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

137、cocoaPods报错 : [!] Unable to add a source with urlhttps://github.com/CocoaPods/Specs.gitnamed master-1.

You can try adding it manually in ~/.cocoapods/repos or via pod repo add.

解决方法：这是因为电脑里安装了另外一个Xcode导致cocoapods找不到路径了

在终端执行 sudo xcode-select -switch /Applications/Xcode.app 即可

138、安装cocoapods的时候出现 ERROR: While executing gem ... (Errno::EPERM)

Operation not permitted - /usr/bin/pod

解决办法：直接在终端执行 sudo gem install -n /usr/local/bin cocoapods

139、在状态栏增加网络请求的菊花，类似safari加载网页的时候状态栏菊花

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

140、检查一个rect是否包含一个point

// point是否在rect内

BOOL isContains = CGRectContainsPoint(rect, point);

141、在指定的宽度下，让UILabel自动设置最佳font

label.adjustsFontSizeToFitWidth = YES;

142、将一个image保存在相册中

UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

或者

import

[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{

    PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

    changeRequest.creationDate          = [NSDate date];

} completionHandler:^(BOOL success, NSError *error) {

    if (success) {

        NSLog(@"successfully saved");

    }

    else {

        NSLog(@"error saving to photos: %@", error);

    }

}];

143、修改cell.imageView的大小

UIImage *icon = [UIImage imageNamed:@""];

CGSize itemSize = CGSizeMake(30, 30);

UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);

CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);

[icon drawInRect:imageRect];

cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

144、为一个view添加虚线边框

CAShapeLayer *border = [CAShapeLayer layer];

border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;

border.fillColor = nil;

border.lineDashPattern = @[@4, @2];

border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;

border.frame = view.bounds;

[view.layer addSublayer:border];

145、UITextView中打开或禁用复制，剪切，选择，全选等功能

// 继承UITextView重写这个方法

• (BOOL)canPerformAction:(SEL)action withSender:(id)sender

{

// 返回NO为禁用，YES为开启

// 粘贴

if (action == @selector(paste:)) return NO;

// 剪切

if (action == @selector(cut:)) return NO;

// 复制

if (action == @selector(copy:)) return NO;

// 选择

if (action == @selector(select:)) return NO;

// 选中全部

if (action == @selector(selectAll:)) return NO;

// 删除

if (action == @selector(delete:)) return NO;

// 分享

if (action == @selector(share)) return NO;

return [super canPerformAction:action withSender:sender];

}

作者：百事小武
链接：https://www.jianshu.com/p/10b2323f502e
來源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。