iOS开发常用的代码（最基础）

%c一个单一的字符

%d一个十进制整数

%i一个整数

%e, %f, %g一个浮点数

%o一个八进制数

%s一个字符串

%x一个十六进制数

%p一个指针

%n一个等于读取字符数量的整数

%u一个无符号整数

%[]一个字符集

%%一个精度符号

//一、NSString

/*----------------创建字符串的方法----------------*/

1、创建常量字符串。

NSString *astring = @"This is a String!";

2、创建空字符串，给予赋值。

NSString *astring = [[NSString alloc] init];

astring = @"This is a String!";

NSLog(@"astring:%@",astring);

[astring release];

3、在以上方法中，提升速度:initWithString方法

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];

NSLog(@"astring:%@",astring);

[astring release];

4、用标准c创建字符串:initWithCString方法

char *Cstring = "This is a String!";

NSString *astring = [[NSString alloc] initWithCString:Cstring];

NSLog(@"astring:%@",astring);

[astring release];

5、创建格式化字符串:占位符（由一个%加一个字符组成）

int i = 1;

int j = 2;

NSString *astring = [[NSString alloc]

initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];

NSLog(@"astring:%@",astring);

[astring release];

6、创建临时字符串

NSString *astring;

astring = [NSString stringWithCString:"This is a temporary string"];

NSLog(@"astring:%@",astring);

/*----------------从文件读取字符串:initWithContentsOfFile方法----------------*/

NSString *path = @"astring.text";

NSString *astring = [[NSString alloc] initWithContentsOfFile:path];

NSLog(@"astring:%@",astring);

[astring release];

/*----------------写字符串到文件:writeToFile方法----------------*/

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];

NSLog(@"astring:%@",astring);

NSString *path = @"astring.text";

[astring writeToFile: path atomically: YES];

[astring release];

/*----------------比较两个字符串----------------*/

用C比较:strcmp函数

char string1[] = "string!";

char string2[] = "string!";

if(strcmp(string1, string2) = = 0)

{

NSLog(@"1");

}

isEqualToString方法

NSString *astring01 = @"This is a String!";

NSString *astring02 = @"This is a String!";

BOOL result = [astring01 isEqualToString:astring02];

NSLog(@"result:%d",result);

compare方法(comparer返回的三种值)

NSString *astring01 = @"This is a String!";

NSString *astring02 = @"This is a String!";

BOOL result = [astring01 compare:astring02] = = NSOrderedSame;

NSLog(@"result:%d",result);

NSOrderedSame判断两者内容是否相同

NSString *astring01 = @"This is a String!";

NSString *astring02 = @"this is a String!";

BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;

NSLog(@"result:%d",result);

//NSOrderedAscending判断两对象值的大小(按字母顺序进行比较，astring02大于astring01为真)

NSString *astring01 = @"this is a String!";

NSString *astring02 = @"This is a String!";

BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;

NSLog(@"result:%d",result);

//NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)

不考虑大 小写比较字符串1

NSString *astring01 = @"this is a String!";

NSString *astring02 = @"This is a String!";

BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;

NSLog(@"result:%d",result);

//NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为 真)

不考虑大小写比较字符串2

NSString *astring01 = @"this is a String!";

NSString *astring02 = @"This is a String!";

BOOL result = [astring01 compare:astring02

options:NSCaseInsensitiveSearch | NSNumericSearch] = = NSOrderedSame;

NSLog(@"result:%d",result);

//NSCaseInsensitiveSearch:不区分大小写比较NSLiteralSearch:进行完全比较，区分大小写NSNumericSearch:比较字符串的字符个数，而不是字符值。

/*----------------改变字符串的大小写----------------*/

NSString *string1 = @"A String";

NSString *string2 = @"String";

NSLog(@"string1:%@",[string1 uppercaseString]);//大写

NSLog(@"string2:%@",[string2 lowercaseString]);//小写

NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小

/*----------------在串中搜索子串----------------*/

NSString *string1 = @"This is a string";

NSString *string2 = @"string";

NSRange range = [string1 rangeOfString:string2];

int location = range.location;

int leight = range.length;

NSString *astring = [[NSString alloc]

initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i"

,location,leight]];

NSLog(@"astring:%@",astring);

[astring release];

/*----------------抽取子串----------------*/

-substringToIndex:从字符串的开头一直截取到指定的位置，但不包括该位置的字符

NSString *string1 = @"This is a string";

NSString *string2 = [string1 substringToIndex:3];

NSLog(@"string2:%@",string2);

-substringFromIndex:以指定位置开始（包括指定位置的字符），并包括之后的全部字符

NSString *string1 = @"This is a string";

NSString *string2 = [string1 substringFromIndex:3];

NSLog(@"string2:%@",string2);

-substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串

NSString *string1 = @"This is a string";

NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];

NSLog(@"string2:%@",string2);

const char *fieldValue = [valuecStringUsingEncoding:NSUTF8StringEncoding];

const char *fieldValue = [value UTF8String];

NSString转NSData

NSString* str= @"kilonet";

NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];

Date format用法：

-(NSString *) getDay:(NSDate *) d

{

NSString *s ;

NSDateFormatter *format = [[NSDateFormatter alloc] init];

[format setDateFormat:@"YYYY/MM/dd hh:mm:ss"];

s = [format stringFromDate:d];

[format release];

return s;

}

各地时区获取：

NSDate *nowDate = [NSDate new];

NSDateFormatter *formatter=[[NSDateFormatter alloc] init];

[formattersetDateFormat:@"yyyy/MM/dd HH:mm:ss"];

//根据时区名字获取当前时间，如果该时区不存在，默认获取系统当前时区的时间

//NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:@"Europe/Andorra"];

//[formatter setTimeZone:timeZone];

//获取所有的时区名字

NSArray *array = [NSTimeZone knownTimeZoneNames];

//NSLog(@"array:%@",array);

//for循环

//for(int i=0;i<[array count];i++)

//{

//NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:[array objectAtIndex:i]];

//[formatter setTimeZone:timeZone];

//NSString *locationTime = [formatter stringFromDate:nowDate];

//NSLog(@"时区名字:%@:时区当前时间: %@",[array objectAtIndex:i],locationTime);

////NSLog(@"timezone name is:%@",[array objectAtIndex:i]);

//}

//快速枚举法

for(NSString *timeZoneName in array){

[formatter setTimeZone:[NSTimeZone timeZoneWithName:timeZoneName]];

NSLog(@"%@,%@",timeZoneName,[formatter stringFromDate:nowDate]);

}

[formatter release];

[nowDate release];

NSCalendar用法：

-(NSString *) getWeek:(NSDate *) d {

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

unsigned units = NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit | NSWeekdayCalendarUnit;

NSDateComponents *components = [calendar components:units fromDate:d];

[calendar release];

switch ([components weekday]) {

case 2:

return @"Monday";

break;

case 3:

return @"Tuesday";

break;

case 4:

return @"Wednesday";

break;

case 5:

return @"Thursday";

break;

case 6:

return@"Friday";

break;

case 7:

return@"Saturday";

break;

case 1:

return @"Sunday";

break;

default:

return @"No Week";

break;

}

//用components，我们可以读取其他更多的数据。

}

4.用Get方式读取网络数据：

将网络数读取为字符串

- (NSString *) getDataByURL:(NSString *) url {

return [[NSString alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]] encoding:NSUTF8StringEncoding];

}

//读取网络图片

- (UIImage *) getImageByURL:(NSString *) url {

return [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]];

}

多线程

[NSThread detachNewThreadSelector:@selector(scheduleTask) toTarget:self withObject:nil];

-(void) scheduleTask {

//create a pool

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

//release the pool;

[pool release];

}

//如果有参数，则这么使用：

[NSThread detachNewThreadSelector:@selector(scheduleTask:) toTarget:self withObject:[NSDate date]];

-(void) scheduleTask:(NSDate *) mdate {

//create a pool

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

//release the pool;

[pool release];

}

//注意selector里有冒号。

//在线程里运行主线程里的方法

[self performSelectorOnMainThread:@selector(moveToMain) withObject:nil waitUntilDone:FALSE];

6.定时器NSTimer用法:

代码

//一个可以自动关闭的Alert窗口

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil

message:[@"一个可以自动关闭的Alert窗口"

delegate:nil

cancelButtonTitle:nil //NSLocalizedString(@"OK", @"OK")//取消任何按钮

otherButtonTitles:nil];

//[alert setBounds:CGRectMake

(alert.bounds.origin.x, alert.bounds.origin.y,

alert.bounds.size.width, alert.bounds.size.height+30.0)];

[alert show];

UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];

// Adjust the indicator so it is up a few pixels from the bottom of the alert

indicator.center = CGPointMake(alert.bounds.size.width/2,alert.bounds.size.height-40.0);

[indicator startAnimating];

[alert insertSubview:indicator atIndex:0];

[indicator release];

[NSTimer scheduledTimerWithTimeInterval:3.0f

target:self

selector:@selector(dismissAlert:)

userInfo:[NSDictionary dictionaryWithObjectsAndKeys:alert,

@"alert", @"testing ", @"key" ,nil]//如果不用传递参数，那么可以将此项设置为nil.

repeats:NO];

NSLog(@"release alert");

[alert release];

-(void) dismissAlert:(NSTimer *)timer{

NSLog(@"release timer");

NSLog([[timer userInfo]objectForKey:@"key"]);

UIAlertView *alert = [[timer userInfo]objectForKey:@"alert"];

[alert dismissWithClickedButtonIndex:0 animated:YES];

}

定时器停止使用：

[timer invalidate];

timer = nil;

7.用户缺省值NSUserDefaults读取：

//得到用户缺省值

NSUserDefaults *defs = [NSUserDefaults standardUserDefaults];

//在缺省值中找到AppleLanguages,返回值是一个数组

NSArray* languages = [defs objectForKey:@"AppleLanguages"];

NSLog(@"all language语言is %@", languages);

//在得到的数组中的第一个项就是用户的首选语言了

NSLog(@"首选语言is %@",[languages objectAtIndex:0]);

//get the language & country code

NSLocale *currentLocale = [NSLocale currentLocale];

NSLog(@"Language Code is %@", [currentLocale objectForKey:NSLocaleLanguageCode]);

NSLog(@"Country Code is %@", [currentLocale objectForKey:NSLocaleCountryCode

8. View之间切换的动态效果设置：

SettingsController *settings = [[SettingsController alloc]initWithNibName:@"SettingsView" bundle:nil];

settings.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;//水平翻转

[self presentModalViewController:settings animated:YES];

[settings release];

9.NSScrollView滑动用法：

-(void) scrollViewDidScroll:(UIScrollView *)scrollView{

NSLog(@"正在滑动中...");

}

//用户直接滑动NSScrollView，可以看到滑动条

-(void) scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

}

//通过其他控件触发NSScrollView滑动，看不到滑动条

- (void) scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {

}

11.键盘处理系列

//set the UIKeyboard to switch to a different text field when you press return

//switch textField to the name of your textfield

[textField becomeFirstResponder];

srandom(time(NULL)); //随机数种子

id d = random(); //随机数

4. iPhone的系统目录:

//得到Document目录：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

//得到temp临时目录：

NSString *tempPath = NSTemporaryDirectory();

//得到目录上的文件地址：

NSString *文件地址= [目录地址stringByAppendingPathComponent:@"文件名.扩展名"];

5.状态栏显示Indicator：

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

6.app Icon显示数字：

- (void)applicationDidEnterBackground:(UIApplication *)application{

[[UIApplication sharedApplication] setApplicationIconBadgeNumber:5];

}

7.sqlite保存地址：

代码

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *thePath = [paths objectAtIndex:0];

NSString *filePath = [thePath stringByAppendingPathComponent:@"kilonet1.sqlite"];

NSString *dbPath = [[[NSBundle mainBundle] resourcePath]

stringByAppendingPathComponent:@"kilonet2.sqlite"];

8.Application退出：exit(0);

9. AlertView，ActionSheet的cancelButton点击事件：

代码

-(void) actionSheet :(UIActionSheet *) actionSheet didDismissWithButtonIndex:(NSInteger) buttonIndex {

NSLog(@"cancel actionSheet........");

//当用户按下cancel按钮

if( buttonIndex == [actionSheet cancelButtonIndex]) {

exit(0);

}

////当用户按下destructive按钮

//if( buttonIndex == [actionSheet destructiveButtonIndex]) {

//// DoSomething here.

//}

}

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {

NSLog(@"cancel alertView........");

if (buttonIndex == [alertView cancelButtonIndex]) {

exit(0);

}

}

10.给Window设置全局的背景图片：

window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"coolblack.png"]];

11. UITextField文本框显示及对键盘的控制:

代码

#pragma mark -

#pragma mark UITextFieldDelegate

//控制键盘跳转

- (BOOL)textFieldShouldReturn:(UITextField *)textField {

if (textField == _txtAccount) {

if ([_txtAccount.text length]==0) {

return NO;

}

[_txtPassword becomeFirstResponder];

} else if (textField == _txtPassword) {

[_txtPassword resignFirstResponder];

}

return YES;

}

//输入框背景更换

-(BOOL) textFieldShouldBeginEditing:(UITextField *)textField{

[textField setBackground:[UIImage imageNamed:@"ctext_field_02.png"]];

return YES;

}

-(void) textFieldDidEndEditing:(UITextField *)textField{

[textField setBackground:[UIImage imageNamed:@"ctext_field_01.png"]];

}

12.UITextField文本框前面空白宽度设置以及后面组合按钮设置：

代码

//给文本输入框后面加入空白

_txtAccount.rightView = _btnDropDown;

_txtAccount.rightViewMode =UITextFieldViewModeAlways;

//给文本输入框前面加入空白

CGRect frame = [_txtAccount frame];

frame.size.width = 5;

UIView *leftview = [[UIView alloc] initWithFrame:frame];

_txtAccount.leftViewMode = UITextFieldViewModeAlways;

_txtAccount.leftView = leftview;

13. UIScrollView设置滑动不超出本身范围：

[fcScrollView setBounces:NO];

14.在drawRect里画文字：

UIFont * f = [UIFont systemFontOfSize:20];

[[UIColor darkGrayColor] set];

NSString * text = @"hi \nKiloNet";

[text drawAtPoint:CGPointMake(center.x,center.y) withFont:f];

15. NSArray查找是否存在对象时用indexOfObject,如果不存在则返回为NSNotFound.

16. NString与NSArray之间相互转换：

array = [string componentsSeparatedByString:@","];

string = [[array valueForKey:@"description"] componentsJoinedByString:@","];

17. TabController随意切换tab bar：

[self.tabBarController setSelectedIndex:tabIndex];

或者self.tabBarController.selectedIndex = tabIndex;

或者实现下面的delegate来扑捉tab bar的事件：

代码-(BOOL) tabBarController:(UITabBarController *)tabBarController

shouldSelectViewController:(UIViewController *)viewController

{if ([viewController.tabBarItem.title isEqualToString: NSLocalizedString(@"Logout",nil)])

{[self showLogout];return NO;}return YES;}

18.自定义View之间切换动画：

代码

- (void) pushController: (UIViewController*) controller

withTransition: (UIViewAnimationTransition) transition

{

[UIView beginAnimations:nil context:NULL];

[self pushViewController:controller animated:NO];

[UIView setAnimationDuration:.5];

[UIView setAnimationBeginsFromCurrentState:YES];

[UIView setAnimationTransition:transition forView:self.view cache:YES];

[UIView commitAnimations];

}

CATransition *transition = [CATransition animation];

transition.duration = kAnimationDuration;

transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

transition.type = kCATransitionPush;

transition.subtype = kCATransitionFromTop;

transitioning = YES;

transition.delegate = self;

[self.navigationController.view.layer addAnimation:transition forKey:nil];

self.navigationController.navigationBarHidden = NO;

[self.navigationController pushViewController:tableViewController animated:YES];

20.计算字符串长度：

CGFloat w = [title sizeWithFont:[UIFont fontWithName:@"Arial" size:18]].width;

23.在使用UISearchBar时，将背景色设定为clearColor，或者将translucent设为YES，都不能使背景透明，经过一番研究，发现了一种超级简单和实用的方法：

1

[[searchbar.subviews objectAtIndex:0]removeFromSuperview];

背景完全消除了，只剩下搜索框本身了。

24.图像与缓存:

UIImageView *wallpaper = [[UIImageView alloc] initWithImage:

[UIImage imageNamed:@"icon.png"]]; //会缓存图片

UIImageView *wallpaper = [[UIImageView alloc] initWithImage:

[UIImage imageWithContentsOfFile:@"icon.png"]]; //不会缓存图片

25. iphone-常用的对视图图层(layer)的操作

对图层的操作：

(1.给图层添加背景图片：

myView.layer.contents = (id)[UIImage imageNamed:@"view_BG.png"].CGImage;

(2.将图层的边框设置为圆脚

myWebView.layer.cornerRadius = 8;

myWebView.layer.masksToBounds = YES;

(3.给图层添加一个有色边框

myWebView.layer.borderWidth = 5;

myWebView.layer.borderColor = [[UIColor colorWithRed:0.52 green:0.09 blue:0.07 alpha:1] CGColor];

将多个字符替换成空

NSCharacterSet *cs = [NSCharacterSet characterSetWithCharactersInString:@"1234567890|"];

NSString *resultstr = [[yourstr componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@" "];

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