从UIViewController返回NSString [英] Return NSString from UIViewController

问题描述

我想从名为InputUIViewController的UIViewController返回一个 NSString * 到之前的UIViewController，名为CallerUIViewController，它启动了InputUIViewController。我想在InputUIViewController调用之前或之时执行：

I want to return a NSString * from a UIViewController, called InputUIViewController, to the previous UIViewController, called CallerUIViewController, which started InputUIViewController. I want to do it just before or when InputUIViewController calls:

[self dismissModelViewControllerAnimated：YES];

有没有一种标准方法可以做到这一点？

Is there a standard way to do this?

推荐答案

标准方式这样做是使用委托。

The standard way to do this would be to use a delegate.

在你的InputViewController中添加一个新的委托协议，以及你的委托的属性。

In your InputViewController add a new delegate protocal, and a property for your delegate.

然后在你的CallerUIViewController中实现委托。然后在你解雇模态视图控制器之前，你可以回调你的委托。

Then in your CallerUIViewController implement the delegate. Then just before your dismiss the modal view controller you can call back to your delegate.

所以你的InputViewController可能如下所示：

So your InputViewController might look like this:

@protocol InputViewControllerDelegate;

@interface InputViewControllerDelegate : UIViewController {
}

@property (nonatomic, assign) id <InputViewControllerDelegate> delegate;

@end


@protocol InputViewControllerDelegate
- (void)didFinishWithInputView:(NSString *)stringValue;
@end

解除模态视图的方法看起来像这样：

The method that dismisses the modal view would look something like this:

-(void)dismissSelf
{
   [self.delegate didFinishWithInputView:@"MY STRING VALUE"];
   [self dismissModalViewControllerAnimated:YES];
}

然后在你的CallerUIViewController中你将实现InputViewControllerDelegate和didFinishWithInputView方法。

Then in your CallerUIViewController you would implement the InputViewControllerDelegate and the didFinishWithInputView method.

CallerUIViewController标题如下所示：

The CallerUIViewController header would look something like:

@interface CallerUIViewController : UIViewController <InputViewControllerDelegate> {
}

并且您的didFinishWithInputView方法将实现如下：

and your didFinishWithInputView method would be implemented something like:

- (void)didFinishWithInputView:(NSString *)stringValue
{
    // This method will be called by the InputViewController just before it is dismissed
}

在您现在的InputViewController之前，您将委托设置为自我。

Just before your present the InputViewController you would set the delegate to self.

-(void)showInputViewController
{
   InputViewController *inputVC = [[InputViewController alloc] init];
   inputVC.delegate = self;

   [self presentModalViewController:inputVC animated:YES];

   [inputVC release];
}

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