iOS开发中一些手写控件及其相关属性的使用

    [downbtn setBackgroundImage:[UIImage imageNamed:@"bottom_highlighted"] forState:UIControlStateHighlighted];
    [downbtn setTag:2];
    //3.把控件添加到视图中
    [self.view addSubview:downbtn];
    
    //4.按钮的单击控制事件
    [downbtn addTarget:self action:@selector(Click:) forControlEvents:UIControlEventTouchUpInside];

    
     /**================向左的按钮=====================*/
    //1.创建按钮对象
    UIButton *leftbtn=[UIButton buttonWithType:UIButtonTypeCustom];
    //2.设置对象的属性
    leftbtn.frame=CGRectMake(50, 300, 40, 40);
    [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal];
    [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_highlighted"] forState:UIControlStateHighlighted];
    [leftbtn setTag:4];
    //3.把控件添加到视图中
    [self.view addSubview:leftbtn];
    
    //4.按钮的单击控制事件
    [leftbtn addTarget:self action:@selector(Click:) forControlEvents:UIControlEventTouchUpInside];
    
    
    
    /**================向右的按钮=====================*/
    //1.创建按钮对象
    UIButton *rightbtn=[UIButton buttonWithType:UIButtonTypeCustom];
    //2.设置对象的属性
    rightbtn.frame=CGRectMake(150, 300, 40, 40);
    [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal];
    [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_highlighted"] forState:UIControlStateHighlighted];
    [rightbtn setTag:3];
    //3.把控件添加到视图中
    [self.view addSubview:rightbtn];
    
    //4.按钮的单击控制事件
    [rightbtn addTarget:self action:@selector(Click:) forControlEvents:UIControlEventTouchUpInside];
    
      //三、写两个缩放按钮
       /**================放大的按钮=====================*/
    //1.创建对象
    UIButton *plusbtn=[UIButton buttonWithType:UIButtonTypeCustom];