iPhone代码片段收集(持续更新)

    1. stringWithFormat 用法：

     [NSString stringWithFormat:@"Hight: %d°%@   Low: %d°%@", [Temp],@"C",[lTemp],@"C"];

       NSString to NSData:

NSString* str=@"kilonet";

NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding]; 

     2. NSDate 用法：

         NSDate  *today;

    NSDate *tomorrow;
    today = [NSDate date];
    tomorrow = [NSDate dateWithTimeInterval:(i*24*60*60) sinceDate:today]; //可能有更好的

         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];
    [formatter    setDateFormat:@"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];

     获取毫秒时间：

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
    //[dateFormatter setDateFormat:@"hh:mm:ss"]
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];
    NSLog(@"Date%@", [dateFormatter stringFromDate:[NSDate date]]);
    [dateFormatter release];

     

      3. 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]]]];
}

     5. 多线程NSThread用法 ：

[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:

  // 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 {

}

   

    10. 读取全局的Delegate：

KiloNetAppDelegate *appdelegate = (KiloNetAppDelegate *)[[UIApplication sharedApplication] delegate];

 

     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];

     12. 半透明层的实现：

+(void)showWaiting:(UIView *)parent {
    int width = 32, height = 32;
    
    CGRect frame = [parent frame]; //[[UIScreen mainScreen] applicationFrame];
    int x = frame.size.width;
    int y = frame.size.height;
    
    frame = CGRectMake((x - width) / 2, (y - height) / 2, width, height);
    UIActivityIndicatorView* progressInd = [[UIActivityIndicatorView alloc] initWithFrame:frame];
    [progressInd startAnimating];
    progressInd.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
    
    
//    frame = CGRectMake((x - 140)/2, (y - height) / 2 + height, 140, 30);
//    UILabel *waitingLable = [[UILabel alloc] initWithFrame:frame];
//    waitingLable.text = @"Proccesing...";
//    waitingLable.textColor = [UIColor whiteColor];
//    waitingLable.font = [UIFont systemFontOfSize:15];
//    waitingLable.backgroundColor = [UIColor clearColor];
    
    frame = [parent frame];
    UIView *theView = [[UIView alloc] initWithFrame:frame];
    theView.backgroundColor = [UIColor blackColor];
    theView.alpha = 0.8;
    
    [theView addSubview:progressInd];
//  [theView addSubview:waitingLable];
    
    [progressInd release];
//    [waitingLable release];
    
    [theView setTag:9999];
    [parent addSubview:theView];
    [theView release];
}

+(void)hideWaiting:(UIView *)parent {
    [[parent viewWithTag:9999] removeFromSuperview];
}

      13. 设置View的圆角：

 // 首先应用  #import <QuartzCore/QuartzCore.h>

view.layer.cornerRadius = 10;
view.layer.masksToBounds = YES;

      14. UIWebView显示本地图片(目前有点问题，无法正确显示图片):

    NSString *imagePath = [[NSBundle mainBundle] resourcePath];
    imagePath = [imagePath stringByReplacingOccurrencesOfString:@"/" withString:@"//"];
    imagePath = [imagePath stringByReplacingOccurrencesOfString:@" " withString:@"%20"];
    
    NSLog(@"fileurl=%@",[NSString stringWithFormat:@"file:/%@//",imagePath]);
    
    //[self loadData:[html dataUsingEncoding:NSUTF8StringEncoding] MIMEType:@"text/html" textEncodingName:@"UTF-8" baseURL:[NSURL fileURLWithPath:[NSString stringWithFormat:@"file:/%@//",imagePath]] ];
    [self loadHTMLString:html baseURL:[NSURL fileURLWithPath:[NSString stringWithFormat:@"file:/%@//",imagePath]   ]];

     NSString *path = [[NSBundle mainBundle] bundlePath];

    NSURL *baseURL = [NSURL fileURLWithPath:path];
    [UIWebView loadHTMLString:html baseURL:baseURL];
    //这段代码可以正确显示图片。