- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //创建一个按钮
    UIButton *button = [[UIButton alloc]init];
   
    //添加到根视图UIView
    [self.view addSubview:button];
    /*
     button在这里是局部变量，会担心{}之后，就被销毁，
     但是addSubview可以将button与self.view之间加上强指针，
     只要self.view没有销毁，button就不会销毁
     */
   
    //设置frame
    button.frame = CGRectMake(112, 100, 150, 150);
   
    //设置文字
    [button setTitle:@"点我啊" forState:UIControlStateNormal];
    [button setTitle:@"哇哇~" forState:UIControlStateHighlighted];

    //创建图片
    UIImage *image1 =[UIImage imageNamed:@"button1"];
    UIImage *image2 =[UIImage imageNamed:@"button2"];
   
    //设置背景图
    [button setBackgroundImage:image1 forState:UIControlStateNormal];
    [button setBackgroundImage:image2 forState:UIControlStateHighlighted];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //创建一个按钮
    UIButton *button = [[UIButton alloc]init];
   
    //添加到根视图UIView
    [self.view addSubview:button];
    /*
     button在这里是局部变量，会担心{}之后，就被销毁，
     但是addSubview可以将button与self.view之间加上强指针，
     只要self.view没有销毁，button就不会销毁
     */
   
    //设置frame
    button.frame = CGRectMake(112, 100, 150, 150);
   
    //设置文字
    [button setTitle:@"点我啊" forState:UIControlStateNormal];
    [button setTitle:@"哇哇~" forState:UIControlStateHighlighted];

    //创建图片
    UIImage *image1 =[UIImage imageNamed:@"button1"];
    UIImage *image2 =[UIImage imageNamed:@"button2"];
   
    //设置背景图
    [button setBackgroundImage:image1 forState:UIControlStateNormal];
    [button setBackgroundImage:image2 forState:UIControlStateHighlighted];
}