//创建UILabel函数- (void) creatUILabel{    //定义并创建一个UILabel对象    UILabel* label = [[UILabel alloc] init];        //文字赋值,字符串对象，设定字体大小，颜色，阴影，阴影偏移量，对齐方式，显示行数(默认1，设为0时智能按合适的行数显示)    label.text = @"你好啊，how are you 你好啊，how are you 你好啊，how are you";    label.font = [UIFont systemFontOfSize:12];    label.textColor = [UIColor blueColor];    label.shadowColor = [UIColor grayColor];    label.shadowOffset = CGSizeMake(2, 1);    label.textAlignment = NSTextAlignmentCenter;    label.numberOfLines = 0;        //设定label的显示位置(左坐标，上坐标，宽，高)    label.frame = CGRectMake(100, 400, 160, 40);        //设定label的背景颜色,clearColor透明色    label.backgroundColor = [UIColor grayColor];        //将label显示到屏幕上    //当前.视图 增加子视图：label    [self.view addSubview:label];}//创建普通按钮函数- (void) createUIRectButton{    //创建圆角按钮    UIButton* btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];    btn.frame = CGRectMake(100, 100, 100, 60);        //设置按钮文字内容，正常状态和按下状态,设置文字颜色    [btn setTitle:@"按钮1" forState:UIControlStateNormal];    [btn setTitle:@"按钮被按下" forState:UIControlStateHighlighted];    [btn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];    [btn setTitleColor:[UIColor redColor] forState:UIControlStateHighlighted];        //设置背景颜色    btn.backgroundColor = [UIColor grayColor];        //添加事件    [btn addTarget:self action:@selector(pressBtn:) forControlEvents:UIControlEventTouchUpInside];        //添加到视图中显示    [self.view addSubview:btn];}//创建显示图片按钮函数- (void) createImageBtn{    //创建一个自定义类型的btn    UIButton* btnImage = [UIButton buttonWithType:UIButtonTypeSystem];    btnImage.frame = CGRectMake(100, 200, 100, 100);        //显示图片    UIImage* icon01 = [UIImage imageNamed:@"2.png"];    [btnImage setImage:icon01 forState:UIControlStateNormal];        //添加事件    [btnImage addTarget:self action:@selector(pressBtn:) forControlEvents:UIControlEventTouchUpInside];        [self.view addSubview:btnImage];        //添加按钮唯一标记    btnImage.tag = 101;    }//响应按钮按下事件函数- (void) pressBtn:(UIButton*) btn{    if(btn.tag == 101){        NSLog(@"hahaha...");    }else{        NSLog(@"hehehe...");        btn.backgroundColor = [UIColor redColor];    }}//程序入口- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.        //调用创建UI函数    [self creatUILabel];    [self createUIRectButton];    [self createImageBtn];}//按钮显示网络图片int all_number = (int)[responseObject[@"data"] count];for (NSInteger i = 0; i < all_number; i++) {	NSURL * imageUrl = [NSURL URLWithString: responseObject[@"data"][i][@"avatar"]];	UIImage * image = [UIImage imageWithData: [NSData dataWithContentsOfURL: imageUrl]];    //设置图片图片为主，不拉伸	//[self.four_site[i] setImage:image forState:normal];    //设置按钮背景图片，按钮为主，图片上的字依然会显示，按钮变大图片会拉伸	[self.four_site[i] setBackgroundImage: image forState: normal];}