目标c，单击按钮时从viewController回调

如何解决目标c，单击按钮时从viewController回调

我有viewController1-主视图控制器和viewController2-这是我的customPopUp。我想在单击button1或button2时从viewController2创建回调。

viewController1代码中的

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
    CustomPopUpViewController *vc = (CustomPopUpViewController *)[storyboard instantiateViewControllerWithIdentifier:@"CustomPopUpViewControllerID"];
    vc.textAlert = text;
    vc.btn1TxtAlert = btn1Txt;
    vc.isAlertOneBtn = YES;

我想做这样的事情：

vc.button1Callback {

}
vc.button2Callback {

}

- viewController2

中的代码

viewController2.h

@interface CustomPopUpViewController : UIViewController
@property (nonatomic,assign) Nsstring* titleAlert;
@property (nonatomic,assign) Nsstring* textAlert;
@property (nonatomic,assign) Nsstring* btn1TxtAlert;
@property (nonatomic,assign) Nsstring* btn2TxtAlert;
@property (nonatomic,assign) BOOL isAlertOneBtn;

viewController2.m

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    _UIbtn2Txt.layer.borderWidth = 2.0f;
    _UIbtn2Txt.layer.borderColor = [UIColor colorWithRed:0.09 green:0.53 blue:0.00 alpha:1.0].CGColor;
    
    _textLbl.text = _textAlert;
    [_UIbtn1Txt setTitle:_btn1TxtAlert forState:UIControlStatenormal];
    [_UIbtn2Txt setTitle:_btn2TxtAlert forState:UIControlStatenormal];
    if(_isAlertOneBtn) {
        _UIbtn2Txt.hidden = YES;
    }
}

- (IBAction)btnAction1:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
       // how i can do callback from this place

}

- (IBAction)btnAction2:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
   // how i can do callback from this place

}

我考虑使用viewController2.h delegete方法创建，就像这样：

@protocol CustomPopUpDelegate;

@interface CustomPopUpViewController : UIViewController


@property (nonatomic,assign) BOOL isAlertOneBtn;

@property (weak)id <CustomPopUpDelegate> delegate;
@end

@protocol CustomPopUpDelegate <NSObject >
    - (id) btn1Action;
    - (id) btn2Action;

@end

在此地点更改

- (IBAction)btnAction1:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
    [self.delegate btn1Action];
}

- (IBAction)btnAction2:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
    [self.delegate btn2Action];

}

然后我无法理解，如何在btn1Action中没有全局实现btn2Action的情况下从CustomPopUpDelegate和viewController1委派动作。

我需要在同一位置从viewController2“ localy”编写回调，例如：

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
        CustomPopUpViewController *vc = (CustomPopUpViewController *)[storyboard instantiateViewControllerWithIdentifier:@"CustomPopUpViewControllerID"];
        vc.textAlert = text;
        vc.btn1TxtAlert = btn1Txt;
        vc.isAlertOneBtn = YES;
    vc.button1Callback {
// how write like this??    
    }
    vc.button2Callback {
    // how write like this??    

    }

解决方法

块是您在这里使用的。您可以说，它们是为此而制成的。

在需要回调的位置创建一个ivar。现在，回调是一个块，您将在需要时执行该代码。因此，块的类型将根据此而变化。这是一些例子...

@property (nonatomic,strong) void ( ^ callbackAction1 )( BOOL ); // Block is named callbackAction1 - it takes a BOOL arg and returns nothing
@property (nonatomic,strong) BOOL ( ^ callbackAction2 )( BOOL ); // Block is named callbackAction2 - it takes a BOOL and returns a BOOL
@property (nonatomic,strong) void ( ^ callbackAction3 )( void ); // Block is named callbackAction3 - it takes nothing and returns nothing

// Real life example
@property (nonatomic,strong)    void ( ^ valueChanged )( XXBooleanCollectionViewCell *,BOOL );

...等等。

然后将这些块链接到您的操作，例如就您而言

- (IBAction)btnAction1:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
    if ( self.callbackAction1 ) {
       // Here we use the block
       self.callbackAction1 ( YES ); // or whatever you need ...
    }
}

有时，如果UI要求您可以在完成块中执行该块，并且如果完成块的格式正确，则您甚至可以将该块作为完成块传递，因此

- (IBAction)btnAction1:(id)sender {
    [self dismissViewControllerAnimated:true completion:callbackAction3];
}

完成后将调用callbackAction3。

然后，要像调用它一样在本地调用它，请按照以下示例更改代码。

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
        CustomPopUpViewController *vc = (CustomPopUpViewController *)[storyboard instantiateViewControllerWithIdentifier:@"CustomPopUpViewControllerID"];
        vc.textAlert = text;
        vc.btn1TxtAlert = btn1Txt;
        vc.isAlertOneBtn = YES;
    vc.button1Callback {
// how write like this??    
    }
    vc.button2Callback {
    // how write like this??    

    }
    // This is how
    vc.callbackAction1 = ^ ( BOOL p ) { 
       if ( p ) something ... the logic of the callback goes in here
    };
    vc.callbackAction2 = ^ BOOL { ... callback logic ... };
    vc.callbackAction3 = ^ { ... };

这是此类事物的常见模式。我对您的逻辑尚不完全清楚，我的回答可能无法完全奏效，所以请告诉我，我会相应地进行更新，但这是工作的重点。

根据您的评论，我认为您的语法有误，应该是

vc.action1 = ^{ ... };

一旦您陷入语法http://goshdarnblocksyntax.com/中，这里就是一个不错的网站。