从图像选择器返回时如何更改视图控制器？

Question

我正在尝试做一些简单的事情：

1. 从控制器MAViewControllerMenu我可以选择现有的图片
2. 选择后，我通过解除选择器视图
返回MAViewControllerMenu
3. 在返回MAViewControllerMenu后，我想切换到另一个控制器MAViewControllerPictureDisplay，在那里我可以看到在imageView中选择的图像。

然而，它并没有把我带到下一个观点。

这是MAViewControllerMenu中的代码

MAViewControllerPictureDisplay* imageControllerView;
- (void)viewDidLoad
{

    [super viewDidLoad];
    // Do any additional setup after loading the view.
    //load next page
    imageControllerView = [[self storyboard]     instantiateViewControllerWithIdentifier:@"chosenImageController"];
}



-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    image = [info objectForKey:UIImagePickerControllerOriginalImage];//Take image from picker
    imageControllerView.image = image;//set it for the next controller's property
    [self dismissViewControllerAnimated:YES completion:^{
    [self.presentingViewController presentModalViewController:imageControllerView
                                                     animated:YES];
}];
    //NEXT LINE DOESNT WORK
    [self presentViewController:imageControllerView animated:YES completion:nil];//THAT DOESNT WORK
}

但是，我在我的第一个控制器中设置了一个按钮，点击它后通过下面的函数在上面运行该行，并且确实将我带到下一个控制器：

- (IBAction)movetonext{
    [self presentViewController:imageControllerView animated:YES completion:nil];
}

我缺少什么？在选择图片后，为什么在点击按钮时调用它但在没有触摸事件时调用时它不起作用？

由于

Answer 1

使用completion处理程序：

-(void)imagePickerController:(UIImagePickerController *)picker 
                                  didFinishPickingMediaWithInfo:(NSDictionary *)info { 
 [self dismissViewControllerAnimated:YES completion:^{
    image = [info valueForKey:UIImagePickerControllerOriginalImage];
    imageControllerView.image = image;
    [self presentViewController:imageControllerView animated:YES completion:nil];
 }];
}

---

<强>样本

Answer 2

试试这个：

而不是弹出UIVIewController，然后呈现。按下两个视图控制器，然后弹出一个。

当您致电选择器时：

  [self presentViewController:imageControllerView animated:NO completion:nil];
  [self presentViewController:PickerController animated:YES completion:nil];

当你解雇时：

   [Picker dismissViewControllerAnimated:YES completion:NULL];

请注意，当我调用两个UIViewController来呈现时，赢得它们（尚未呈现的那个）的动画设置为“NO”。

希望这有帮助

修改

以上代码仅适用于UINaviationController，“PushViewController”和“PopViewController”。

我发现实现这一目标的唯一两种方法是：

1 - 如果您使用NSNotificationCenter来解除您的middel视图，如下所示：

Dismiss 2 modal view controllers

不幸的是，它不是同一个案例，所以我想到使用UINaviationController的方式 对你来说，就是使用UIImagePicker的子视图来解散他的自我......

2 - 知道这是一种黑客行为，但它确实有效！如果你打电话来呈现middel UIViewController，没有动画，并从该视图调用图像选择器，它将工作。你必须委托回来的图像。 我添加到我的代码中，为middel UIViewController首次将Alpha设置为0，所以你不会注意到，他是赢得了如何呈现：

//First UIViewController:

@implementation ViewControllerOne
- (IBAction)buttonPressed:(id)sender {

    ViewControllerTwo *viewTwo = [[ViewControllerTwo alloc]init];
    [self presentViewController:viewTwo animated:NO completion:nil];
}

//Secound UIViewController:
      @interface ViewControllerTwo ()
       @property (nonatomic) UIImagePickerController *myPicker;
       @end
       @implementation ViewControllerTwo

       -(void)viewWillAppear:(BOOL)animated
       {
       //View to alph 0 if this is the first time it displayis:
       if (!self.myPicker) {
         [self.view setAlpha:0];
      }else{
        [self.view setAlpha:1];
       }
      }
      -(void)viewDidAppear:(BOOL)animated{

      if (!self.myPicker) {
        self.myPicker = [[UIImagePickerController alloc]init];
        self.myPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        self.myPicker.delegate = self;
        [self presentViewController:self.myPicker animated:YES completion:nil];
      }
      }  
       - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:    (NSDictionary *)info
      {
    [self.myPicker dismissViewControllerAnimated:YES completion:nil];
      }
      - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
      {
    [self.myPicker dismissViewControllerAnimated:YES completion:NO];
      }
      - (IBAction)ButtonTwoClicked:(id)sender {
       [self dismissViewControllerAnimated:YES completion:NO];
     }