ChildViewSampleViewController.h

@interface ChildViewSampleViewController : UIViewController @end

ChildViewSampleViewController.m

@interface ChildViewSampleViewController ()@property (nonatomic) UIViewController *root;@property (nonatomic) UIViewController *overlap;@property (nonatomic) UIButton *button;@end @implementation ChildViewSampleViewController - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization    }    return self;} - (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.         self.root = [[UIViewController alloc] init];    self.root.view.frame = CGRectMake(0, 60, 320, self.view.frame.size.height - 60);    [self.root.view setBackgroundColor:[UIColor yellowColor]];         [self addChildViewController:self.root];    [self.root didMoveToParentViewController:self];    [self.view addSubview:self.root.view];              self.button = [[UIButton alloc] initWithFrame:CGRectMake(10, 10, 150, 50)];    [self.button setTitle:@"Show" forState:UIControlStateNormal];    [self.button addTarget:self action:@selector(pop:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:self.button];} #pragma mark - Event-(void)pop:(id)sender {    if (self.overlap == nil ) {        // Open(Show)        self.overlap = [[UIViewController alloc] init];        [self.overlap.view setBackgroundColor:[UIColor redColor]];        [self addChildViewController:self.overlap];                 // Start line        CGRect startFrame = self.view.frame;        startFrame.origin.y = startFrame.size.height;        self.overlap.view.frame = startFrame;                 // Move half        [self transitionFromViewController:self.root                          toViewController:self.overlap                                  duration:1.0                                   options:0                                animations:^{                                    CGRect original = self.root.view.frame;                                    self.overlap.view.frame = CGRectMake(0, original.origin.y, original.size.width, original.size.height);                                }                                completion:^(BOOL finished) {                                    [self.overlap didMoveToParentViewController:self];                                    [self.button setTitle:@"Hide" forState:UIControlStateNormal];                                }];    }    else {        // Hide        [self.overlap willMoveToParentViewController:nil];                 // Good-bye        [self transitionFromViewController:self.overlap                          toViewController:self.root                                  duration:1.0                                   options:0                                animations:^{                                    CGRect original = self.root.view.frame;                                    self.overlap.view.frame = CGRectMake(0, original.size.height, original.size.width, original.size.height);                                    [self.overlap.view.superview bringSubviewToFront:self.overlap.view];                                                                     }                                completion:^(BOOL finished) {                                    [self.overlap removeFromParentViewController];                                    self.overlap = nil;                                    [self.button setTitle:@"Show" forState:UIControlStateNormal];                                }];    }} @end

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