Question

MyAlertView（UIAlertView的子类）有这个方法：

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
    if (self.clickedButtonAtIndexBlock != NULL)
        self.clickedButtonAtIndexBlock(buttonIndex);
}

我的问题是如何在创建警报视图时定义回调？显然这是错误的：

alert.clickedButtonAtIndexBlock = ^{
    NSLog(@"clicked: %d", buttonIndex);
}

Answer 1

我写了一篇关于如何（以及为什么）添加块回调以提醒视图，操作表和动画的博客文章：

http://blog.innovattic.com/uikitblocks/

如果你只是想要一个有效的实现，你可以从GitHub下载源文件：

https://github.com/Innovattic/UIKit-Blocks

用法：

UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"My easy alert"  
                                                message:@"Would you like to perform some kind of action?"
                                      cancelButtonTitle:@"No"
                                      otherButtonTitles:@"Yes", nil];
[alert setHandler:^(UIAlertView* alert, NSInteger buttonIndex) {
    NSLog(@"Perform some kind of action");
} forButtonAtIndex:[alert firstOtherButtonIndex]];
[alert show];

Answer 2

尝试做这样的事情（我还没有测试过）：

.h
typedef void (^MyClickedIndexBlock)(NSInteger index);

@interface YouInterface : YourSuperclass
@property (nonatomic, strong) MyClickedIndexBlock clickedIndexBlock;
@end

.m
//where you have to call the block
if (self.clickedIndexBlock != nil)
    self.clickedIndexBlock(buttonIndex);

// where you want to receive the callback
alert.clickedIndexBlock = ^(NSInteger index){
    NSLog(@"%d", index);
};

Answer 3

检查这个OpinionzAlertView我在几个项目中使用它，对我有用。这是样本：

OpinionzAlertView *alert = [[OpinionzAlertView alloc] initWithTitle:@"title"
                                                            message:@"message"
                                                  cancelButtonTitle:@"No, thanks"
                                                  otherButtonTitles:@[@"Done"]
                                            usingBlockWhenTapButton:^(OpinionzAlertView *alertView, NSInteger buttonIndex) {

                                                NSLog(@"buttonIndex: %li", (long)buttonIndex);
                                                NSLog(@"buttonTitle: %@", [alertView buttonTitleAtIndex:buttonIndex]);
                                            }];
[alert show];

我希望它会对你有所帮助。

Answer 4

试试这个

假设您创建了一个名为MyCustomAlert的类，并将其声明为此变量。

MyCustomAlert *myCustomAlert = [[MyCustomAlent alloc] init];

您可以将其放在头文件中。

- (void)setCompletion:(void (^)(int selectedButtonIndex))completion;

你会把它放在你的实现文件中

typedef void (^IntBlock)(int intBlock);
IntBlock _completion;

- (void)setCompletion:(void (^)(int selectedButtonIndex))completion{
    _completion = completion;
}

现在在您声明“myCustomAlert”的项目中。如果您输入

[myCustomAlert setCompletion: // And select the autocomplete item

你最终会得到这个

[myCustomAlert setCompletion:<#^(int intBlock)completion#>]

值＆lt;＃^（int intBlock）完成＃＆gt;会像这样出现泡泡。

enter image description here

当您按下输入值时，它将填写阻止您使用。

[myCustomAlert setCompletion:^(int selectedButtonIndex) {

}

如果要在自定义类中触发_completion块，可以在代码中的某处调用它，如下所示。

- (void) callCompletionWithButtonIndex:(int) index{
    if (_completion != nil) _completion(index);
}

希望能够解决并发症。

Answer 5

我编写了一个简单的类LMSVBlocks来轻松显示警报并在一行中获得块回调。希望你会发现它对此有用

https://github.com/sourabhverma/LMSVBlocks

概念：要使UIAlertView块兼容，您需要另一个类（Say LMSVBlockAlert）来处理委托方法，当UIAlertView委托给出回调时，LMSVBlockAlert类可以在块中发送回调。

<强>代码：（LMSVBlockAlert.m）

在数组中维护LMSVBlockAlert的所有实例，以便它们具有强引用

static NSMutableArray *_LMSVblockHandlersArray = nil;

将块处理程序保留在LMSVBlockAlert

中

@interface LMSVBlockAlert() <UIAlertViewDelegate>
@property (nonatomic, copy) void (^cancelCompletionBlock)();
@property (nonatomic, copy) void (^confirmCompletionBlock)();
@end

当触发新警报时，创建具有UIAlertView和委托回调的LMSVBlockAlert的新实例

+(LMSVBlockAlert*)newInstance{
    LMSVBlockAlert *newIns = [[LMSVBlockAlert alloc] init];
    [LMSVBlockAlert updateHandlerArrayWith:newIns];
    return newIns;
}

当在LMSVBlockAlert中触发警告委托时，发送回调以阻止并从内存中清除它

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{

    switch (buttonIndex) {
        case 0://Cancel
        {
            if(_cancelCompletionBlock){
                _cancelCompletionBlock();
            }
        }
            break;
        case 1://OK
        {
            if(_confirmCompletionBlock){
                _confirmCompletionBlock(alertView);
            }
        }
            break;
        default:
            break;
    }
    [_LMSVblockHandlersArray removeObject:self];
}

现在您可以使用两个简单的方法来为您提供UIAlertView回调

+(UIAlertView*)promptAlertTwoBtn:(NSString*)msg title:(NSString*)title onCancel:(void (^)())onCancel onConfirm:(void (^)())onConfirm{

    return [[LMSVBlockAlert newInstance] showAlertMainWithTitle:title msg:msg onCancel:^{
        onCancel();
    } onConfirm:^(UIAlertView *alertView) {
        onConfirm();
    }];
}

-(UIAlertView*)showAlertMainWithTitle:(NSString*)title msg:(NSString*)msg onCancel:(void (^)())onCancel onConfirm:(void (^)(UIAlertView*))onConfirm{

    UIAlertView *newAlert = nil;


    newAlert = [[UIAlertView alloc]
                    initWithTitle:title
                    message:msg
                    delegate:self
                    @"Cancel"
                    otherButtonTitles:@"Confirm", nil];


    [newAlert show];

    self.cancelCompletionBlock = onCancel;
    self.confirmCompletionBlock = onConfirm;

    return newAlert;
}

<强>最后希望你发现它很有用..

Answer 6

您可以从github简单地使用这些类别类。

Alert_ActionSheetWithBlocks

这为AlertView和操作表提供了Dismiss块。

对于例如。

UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"AlertView+Block" message:@"WithBlocks" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"newAlertViewWithTextFields",@"newAlertViewWithSingleTextField", nil];
[alert showWithFinishBlock:^(UIAlertView *alertView, NSInteger buttonIndex) 
{ if (buttonIndex == 0) { } else if (buttonIndex == 1) { } }];

除此之外，它还提供文本字段的方法..

-(void) showWithFinishBlock:(FinishBlock_)block_; //-- AlertView with TextField [simple or secure]

-(void) showWithTextFieldBlock:(TextFieldBlock_)block_ secure:(BOOL)isSecure; //-- AlertView with two textfields username & password

您可以查看与其捆绑的示例。我希望它对你有所帮助。

Answer 7

我在Swift中编写了一个简单的扩展，希望它有用

import UIKit

extension UIAlertView {

    func show(completion: (alertView: UIAlertView, buttonIndex: Int) -> Void){
        self.delegate = AlertViewDelegate(completion: completion)
        self.show()
    }

    class func showInput(title: String?, message: String?, cancellable: Bool, completion: (text: String?) -> Void){

        var strOK = NSLocalizedString("OK",comment: "OK")
        var strCancel = NSLocalizedString("Cancel",comment: "Cancel")
        var alert = UIAlertView(title: title, message: message, delegate: nil, cancelButtonTitle: cancellable ? strCancel : strOK)
        alert.alertViewStyle = UIAlertViewStyle.PlainTextInput
        if(cancellable) {
            alert.addButtonWithTitle(strOK)
        }
        alert.show { (alertView, buttonIndex) -> Void in
            if(cancellable && alertView.cancelButtonIndex == buttonIndex) {
                completion(text: nil)
                return
            }
            completion(text: alertView.textFieldAtIndex(0)?.text)
        }
    }

    private class AlertViewDelegate : NSObject, UIAlertViewDelegate {
        var completion :  (alertView: UIAlertView, buttonIndex: Int) -> Void
        var retainedSelf : NSObject?
        init(completion: (UIAlertView, Int) -> Void ) {
            self.completion = completion
            super.init()

            self.retainedSelf = self
        }

        func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int) {
            var retain = self
            retain.retainedSelf = nil
            retain.completion(alertView: alertView, buttonIndex: buttonIndex)
        }
    }
}

使用块回调自定义UIAlertView

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