日常Ios开发常用的技巧 自用 不断完善中...
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0if(indexPath.row==YouWantToHideRow)return0;return44;}// 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)
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:0.5foptions: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
build phases
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();returnimage;}
22、view设置圆角
#defineViewBorderRadius(View, Radius, Width, Color)\\[View.layersetCornerRadius:(Radius)];\[View.layersetMasksToBounds:YES];\[View.layersetBorderWidth:(Width)];\[View.layersetBorderColor:[ColorCGColor]]// view圆角
23、强／弱引用
#defineWeakSelf(type)__weaktypeof(type)weak##type=type;// weak#defineStrongSelf(type)__strongtypeof(type)type=weak##type;// strong
24、由角度转换弧度
#defineDegreesToRadian(x) (M_PI * (x) / 180.0)
25、由弧度转换角度
#defineRadianToDegrees(radian) (radian*180.0)/(M_PI)
26、获取图片资源
#defineGetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]
27、获取temp
#definePathTemp NSTemporaryDirectory()
28、获取沙盒 Document
#definePathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]
29、获取沙盒 Cache
#definePathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]
30、GCD代码只执行一次
#definekDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);
31、自定义NSLog
#ifdefDEBUG#defineNSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)#else#defineNSLog(...)#endif
32、Font
#defineFontL(s) [UIFont systemFontOfSize:s weight:UIFontWeightLight]#defineFontR(s) [UIFont systemFontOfSize:s weight:UIFontWeightRegular]#defineFontB(s) [UIFont systemFontOfSize:s weight:UIFontWeightBold]#defineFontT(s) [UIFont systemFontOfSize:s weight:UIFontWeightThin]#defineFont(s) FontL(s)
33、FORMAT
#defineFORMAT(f, ...) [NSString stringWithFormat:f, ## __VA_ARGS__]
34、在主线程上运行
#definekDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);
35、开启异步线程
#definekDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);
36、通知
#defineNOTIF_ADD(n, f) [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]#defineNOTIF_POST(n, o) [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]#defineNOTIF_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/255.0fgreen:aGreenValue/255.0fblue:aBlueValue/255.0falpha:1.0f];returnrandColor;}
38、获取window
+(UIWindow*)getWindow{UIWindow*win=nil;//[UIApplication sharedApplication].keyWindow;for(id itemin[UIApplication sharedApplication].windows){if([item class]==[UIWindow class]){if(!((UIWindow*)item).hidden){win=item;break;}}}returnwin;}
39、修改textField的placeholder的字体颜色、大小
[textFieldsetValue:[UIColor redColor]forKeyPath:@"_placeholderLabel.textColor"];[textFieldsetValue:[UIFontboldSystemFontOfSize: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{returnYES;}/** 支持哪些屏幕方向 */-(UIInterfaceOrientationMask)supportedInterfaceOrientations{returnUIInterfaceOrientationMaskLandscapeLeft|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{returnUIInterfaceOrientationLandscapeLeft|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*fileNameinenumerator){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MCGFloat totalSize=((CGFloat)imageCacheSize+count)/1024/1024;returntotalSize;}
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
staticNSSet*classes;-(NSMutableDictionary*)getParameterDictionary{NSMutableDictionary*dict=[NSMutableDictionary dictionary];Class c=self.class;while(c){unsignedcount;objc_property_t*properties=class_copyPropertyList([c class],&count);for(inti=0;i<count;i++){NSString*key=[NSString stringWithUTF8String:property_getName(properties[i])];dict[key]=[selfvalueForKey:key];}free(properties);// 获得父类c=class_getSuperclass(c);if([selfisClassFromFoundation:c])break;}returndict;}-(BOOL)isClassFromFoundation:(Class)c{if(c==[NSObject class]||c==[NSManagedObject class])returnYES;__block BOOL result=NO;[[selffoundationClasses]enumerateObjectsUsingBlock:^(Class foundationClass,BOOL*stop){if([c isSubclassOfClass:foundationClass]){result=YES;*stop=YES;}}];returnresult;}-(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];}returnclasses;}
45、交换两个方法实现
Class aClass=[selfclass];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";returnplatform;}
49、长按复制功能
-(void)viewDidLoad{[self.view addGestureRecognizer:[[UILongPressGestureRecognizer alloc]initWithTarget:selfaction:@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){case0xFF:return@"jpeg";case0x89:return@"png";case0x47:return@"gif";case0x49:case0x4D:return@"tiff";case0x52:if([data length]<12){returnnil;}NSString*testString=[[NSString alloc]initWithData:[data subdataWithRange:NSMakeRange(0,12)]encoding:NSASCIIStringEncoding];if([testString hasPrefix:@"RIFF"]&&[testString hasSuffix:@"WEBP"]){return@"webp";}returnnil;}returnnil;}
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");unsignedintoutCount,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[selfdrawInRect:rect];UIImage*image=UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();returnimage;}
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];returnresponseJSON;}
58、身份证号验证
-(BOOL)validateIdentityCard{BOOL flag;if(self.length<=0){flag=NO;returnflag;}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{intmib[6];size_t len;char*buf;unsignedchar*ptr;structif_msghdr*ifm;structsockaddr_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");returnNULL;}if(sysctl(mib,6,NULL,&len,NULL,0)<0){printf("Error: sysctl, take 1\n");returnNULL;}if((buf=malloc(len))==NULL){printf("Could not allocate memory. Rrror!\n");returnNULL;}if(sysctl(mib,6,buf,&len,NULL,0)<0){printf("Error: sysctl, take 2");returnNULL;}ifm=(structif_msghdr*)buf;sdl=(structsockaddr_dl*)(ifm+1);ptr=(unsignedchar*)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);returnoutstring;}
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[selfgetVisibleViewControllerFrom:[((UINavigationController*)vc)visibleViewController]];}elseif([vc isKindOfClass:[UITabBarController class]]){return[selfgetVisibleViewControllerFrom:[((UITabBarController*)vc)selectedViewController]];}else{if(vc.presentedViewController){return[selfgetVisibleViewControllerFrom:vc.presentedViewController];}else{returnvc;}}}
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[selfaddObserver:selfforKeyPath: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"]){[selftextViewTextChange];}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){caseAFNetworkReachabilityStatusUnknown:break;caseAFNetworkReachabilityStatusNotReachable:{[SVProgressHUD showInfoWithStatus:@"当前设备无网络"];}break;caseAFNetworkReachabilityStatusReachableViaWiFi:[SVProgressHUD showInfoWithStatus:@"当前Wi-Fi网络"];break;caseAFNetworkReachabilityStatusReachableViaWWAN:[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)returnnil;CGImageRef imageRef=self.CGImage;NSUInteger width=CGImageGetWidth(imageRef);NSUInteger height=CGImageGetHeight(imageRef);if(point.x>=width||point.y>=height)returnnil;unsignedchar*rawData=malloc(height*width*4);if(!rawData)returnnil;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);returnnil;}CGColorSpaceRelease(colorSpace);CGContextDrawImage(context,CGRectMake(0,0,width,height),imageRef);CGContextRelease(context);intbyteIndex=(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);returnresult;
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{intwidth=sourceImage.size.width;intheight=sourceImage.size.height;CGColorSpaceRef colorSpace=CGColorSpaceCreateDeviceGray();CGContextRef context=CGBitmapContextCreate(nil,width,height,8,0,colorSpace,kCGImageAlphaNone);CGColorSpaceRelease(colorSpace);if(context==NULL){returnnil;}CGContextDrawImage(context,CGRectMake(0,0,width,height),sourceImage.CGImage);CGImageRef contextRef=CGBitmapContextCreateImage(context);UIImage*grayImage=[UIImage imageWithCGImage:contextRef];CGContextRelease(context);CGImageRelease(contextRef);returngrayImage;}
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];}returnnil;}
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();returnimage;}
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:1.0green:1.0blue:1.0alpha: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=[supertextRectForBounds:bounds limitedToNumberOfLines:numberOfLines];switch(self.textAlignmentType){caseWZBTextAlignmentTypeLeftTop:{rect.origin=bounds.origin;}break;caseWZBTextAlignmentTypeRightTop:{rect.origin=CGPointMake(CGRectGetMaxX(bounds)-rect.size.width,bounds.origin.y);}break;caseWZBTextAlignmentTypeLeftBottom:{rect.origin=CGPointMake(bounds.origin.x,CGRectGetMaxY(bounds)-rect.size.height);}break;caseWZBTextAlignmentTypeRightBottom:{rect.origin=CGPointMake(CGRectGetMaxX(bounds)-rect.size.width,CGRectGetMaxY(bounds)-rect.size.height);}break;caseWZBTextAlignmentTypeTopCenter:{rect.origin=CGPointMake((CGRectGetWidth(bounds)-CGRectGetWidth(rect))/2,CGRectGetMaxY(bounds)-rect.origin.y);}break;caseWZBTextAlignmentTypeBottomCenter:{rect.origin=CGPointMake((CGRectGetWidth(bounds)-CGRectGetWidth(rect))/2,CGRectGetMaxY(bounds)-CGRectGetMaxY(bounds)-rect.size.height);}break;caseWZBTextAlignmentTypeLeft:{rect.origin=CGPointMake(0,rect.origin.y);}break;caseWZBTextAlignmentTypeRight:{rect.origin=CGPointMake(rect.origin.x,0);}break;caseWZBTextAlignmentTypeCenter:{rect.origin=CGPointMake((CGRectGetWidth(bounds)-CGRectGetWidth(rect))/2,(CGRectGetHeight(bounds)-CGRectGetHeight(rect))/2);}break;default:break;}returnrect;}-(void)drawTextInRect:(CGRect)rect{CGRect textRect=[selftextRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];[superdrawTextInRect: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
cell
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1if([str1 containsString:str2]){NSLog(@"str1包含str2");}else{NSLog(@"str1不包含str2");}// 方法2if([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[<ViewController 0x7fea6ed05980> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key的crash
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:@""];returntemp;}
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returnYES;}else{//没有空格returnNO;}}
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:NULLerror:&err];UIImage*one=[[UIImage alloc]initWithCGImage:oneRef];returnone;
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];intseconds=ceil(time.value/time.timescale);returnseconds;}
92、字符串是否为空
+(BOOL)isEqualToNil:(NSString*)str{returnstr.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
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 (<UITableView: 0x7ff19b027000; >) failed to obtain a cell from its dataSource (<ViewController: 0x7ff19a507520>)
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:.5animations:^{[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 keyindict){[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{[superviewDidAppear:animated];if([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]){self.navigationController.interactivePopGestureRecognizer.delegate=self;}}-(void)viewWillDisappear:(BOOL)animated{[superviewWillDisappear:animated];if([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]){self.navigationController.interactivePopGestureRecognizer.delegate=nil;}}-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer*)gestureRecognizer{returnNO;}
107、模拟器报错
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};[superdrawTextInRect: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];[superdrawTextInRect:rect];// 文本颜色self.textColor=[UIColor yellowColor];CGContextSetTextDrawingMode(c,kCGTextFill);[superdrawTextInRect: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
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#importAudioServicesPlayAlertSound(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[selfbecomeFirstResponder];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=[selfsuperview];next;next=next.superview){UIResponder*nextResponder=[next nextResponder];if([nextResponder isKindOfClass:[UIViewController class]]){return(UIViewController*)nextResponder;}}returnnil;}
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:[UIColorclearColor]];[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){constCGFloat*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);returncolor;}elsereturncolor;};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.gitnamedmaster-1.
You can try adding it manually in~/.cocoapods/reposor viapod 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:67/255.0fgreen:37/255.0fblue:83/255.0falpha: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:))returnNO;// 剪切if(action==@selector(cut:))returnNO;// 复制if(action==@selector(copy:))returnNO;// 选择if(action==@selector(select:))returnNO;// 选中全部if(action==@selector(selectAll:))returnNO;// 删除if(action==@selector(delete:))returnNO;// 分享if(action==@selector(share))returnNO;return[supercanPerformAction:action withSender:sender];}
