iOS开发实现简单抽屉效果

//两个子控制器leftView和midView
@property(nonatomic,weak)UIViewController *leftView;
@property(nonatomic,weak)UIViewController *midView;

- (void)viewDidLoad {
    [super viewDidLoad];

    //将leftView和midView添加到self中作为子控制器。将他们的view添加到self.view中
    [self addChildViewController:self.leftView];
    [self.view addSubview:self.leftView.view];
    [self addChildViewController:self.midView];
    [self.view addSubview:self.midView.view];

    //设置一个按钮点击实现抽屉效果
    UIButton *leftButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    leftButton.frame = CGRectMake(0, 50, 150, 150);
    [leftButton addTarget:self action:@selector(leftButtonPressed) forControlEvents:UIControlEventTouchUpInside];
    [leftButton setTitle:@"left" forState:UIControlStateNormal];
    [self.midView.view addSubview:leftButton];

}

-(void)leftButtonPressed
{
    //判断抽屉是否是展开状态
    if (self.midView.view.frame.origin.x == 0) {

        //通过动画实现view.fram的改变
        [UIView animateWithDuration:0.3 animations:^{
            /*  W  H  屏幕实际大小宏
             * #define ScreenWidth [UIScreen mainScreen].bounds.size.width
             * #define ScreenHeight [UIScreen mainScreen].bounds.size.height
            */
            self.leftView.view.frame = CGRectMake(0, 0, W, H);
            self.midView.view.frame = CGRectMake(200, 50, W, H-50*2);

        } completion:^(BOOL finished) {
        }];

    }else{

        [UIView animateWithDuration:0.3 animations:^{

            self.midView.view.frame = CGRectMake(0, 0, W, H);

        } completion:^(BOOL finished) {
        }];
    }
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    LeftViewController *leftView = [[LeftViewController alloc] init];
    MidViewController *midView = [[MidViewController alloc]init];
    RootViewController *rootView = [[RootViewController alloc]init];
    rootView.leftView = leftView;
    rootView.midView = midView;
    self.window.rootViewController = rootView;
    [self.window makeKeyAndVisible];
    return YES;
}