無法在第一個視圖控制器頂部嵌入第二個視圖控制器

Question

使用下面的代碼在第二個視圖控制器頂部顯示第一個視圖控制器就像對話框一樣。

[self addChildViewController:viewController]; 
viewController.view.frame = self.view.frame; 
[self.view addSubview:viewController.view]; 
viewController.view.alpha = 0; 
[viewController didMoveToParentViewController:self]; 

[UIView animateWithDuration:0.25 delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^ 
{ 
    viewController.view.alpha = 1; 
} 
       completion:nil]; 

但第二個視圖控制器是不可見的...我如何能排序了這一點？

Answer 1

必須有，你犯的錯誤代碼，我寫了一個演示： 我寫兩個控制器這樣的：

在vc1：

#import "ViewController.h" 
#import "ViewController2.h" 

@interface ViewController() 

@end 

@implementation ViewController 

- (void)viewDidLoad { 
    [super viewDidLoad]; 

    [self initUI]; 
} 

#pragma mark - init 

- (void)initUI { 

self.view.backgroundColor = [UIColor whiteColor]; 

A) If use storyboard, init vc2 like this : 
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; 
ViewController2 *vc2 = [sb instantiateViewControllerWithIdentifier:@"ViewController2"]; 

B)If use code ,init vc2 like this: 
ViewController2 *vc2 = [[ViewController2 alloc] init]; 


[self addChildViewController:vc2]; 
vc2.view.frame = self.view.bounds 
[self.view addSubview:vc2.view]; 
vc2.view.alpha = 0; 
[vc2 didMoveToParentViewController:self]; 

[UIView animateWithDuration:0.25 delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^ 
    { 
     vc2.view.alpha = 1; 
    } 
       completion:nil]; 
} 

@end 

在vc2：

#import "ViewController2.h" 

@interface ViewController2() 

@end 

@implementation ViewController2 

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view. 

    self.view.backgroundColor = [UIColor brownColor]; 

} 

Answer 2

1. 嘗試[parentView bringSubviewToFront:childView];

2. 嘗試viewController.view.frame = self.view.bounds;

3. 做檢查，如果你有實例viewController正常。