添加按鈕：

      UIButton * btn = [UIButton buttonWithType:(UIButtonTypeRoundedRect)];     btn.frame = CGRectMake(100, 100, 100, 100);     [btn addTarget:self action:@selector(btnPressed:) forControlEvents:(UIControlEventTouchUpInside)];     [btn setTitle:@"確定" forState:(UIControlStateNormal)];     [self.view addSubview:btn];   添加label：       UILabel * lbl = [[UILabel alloc]initWithFrame:CGRectMake(10, 10, 100, 44)];     lbl.text = @"test";     lbl.textColor = [UIColor purpleColor];     lbl.font = [UIFont systemFontOfSize:18];     lbl.backgroundColor = [UIColor clearColor];     [self.view addSubview:lbl];   添加view：       UIView * aView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 80)];     aView.backgroundColor = [UIColor purpleColor];     [self.view addSubview:aView];   view為圓角：     需要：#import <QuartzCore/QuartzCore.h>       aView.layer.cornerRadius = 10;   給view添加手勢：       UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGesture)];     [self.view addGestureRecognizer:tap];   添加textField以及delegate方法：     需要：UITextFieldDelegate協議       UITextField * text = [[UITextField alloc]initWithFrame:CGRectMake(0, 50, 320, 44)];     text.backgroundColor = [UIColor purpleColor];     text.placeholder = @"請輸入：";     text.borderStyle = UITextBorderStyleRoundedRect;     text.font = [UIFont systemFontOfSize:18];     text.textAlignment = NSTextAlignmentLeft;     //[text setContentMode:UIViewContentModeCenter];       [text setContentVerticalAlignment:(UIControlContentVerticalAlignmentCenter)];//內容在中間，上下     text.delegate = self;     [self.view addSubview:text];      #pragma mark - textField delegate    - (BOOL)textFieldShouldReturn:(UITextField *)textField{       [textField resignFirstResponder];       return YES;   }   textField的邊框寬度和邊框顏色：     需要：#import <QuartzCore/QuartzCore.h>       text.layer.borderWidth = 1;       text.layer.borderColor = [UIColor redColor].CGColor;   定義size大小：    CGSize size = [str sizeWithFont:[UIFont systemFontOfSize:20] constrainedToSize:CGSizeMake(320, 1000) lineBreakMode:(NSLineBreakByWordWrapping)];   播放音樂：     需要添加AVFoundation.framework框架     需要:#import <AVFoundation/AVFoundation.h>   NSURL *url = [NSURL URLWithString:@"http://zhangmenshiting.baidu.com/data2/music/903505/8930817375600128.mp3?xcode=750b4fdc9f5eeb0954dfe54c6e23e3be24b7b177cb0d29e2&amp;song_id=89308173"];     NSData *urlData = [NSData dataWithContentsOfURL:url];     NSError *error = nil;     AVAudioPlayer * player = [[[AVAudioPlayer alloc]initWithData:urlData error:&error] autorelease];     //准備播放音樂     [player prepareToPlay];     [player play];   添加風火輪：    需要添加 QuartzCore.framework框架     需要：#import <QuartzCore/QuartzCore.h>       UIActivityIndicatorView * active = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:(UIActivityIndicatorViewStyleWhiteLarge)];     active.backgroundColor = [UIColor grayColor];     active.alpha = 0.5;     active.layer.cornerRadius = 10;     active.frame = CGRectMake(100, 100, 80, 80);     [self.view addSubview:active];     [active startAnimating];