iphone - 阻止 UIAlertViewDelegate

Question

我是 Objective-C 的新手，我只是想弄清楚我是否可以使用 block 或选择器作为 UIAlertView 的 UIAlertViewDelegate 参数 - 哪个更合适？

我已经尝试了以下方法，但它不起作用，所以我不确定我是否在正确的轨道上？

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Checked In" 
    message:responseString
    delegate:^(UIAlertView * alertView, NSInteger buttonIndex)
                                                    {
                                                       NSLog(@"Done!");
                                                   } 
    cancelButtonTitle:@"OK" 
    otherButtonTitles: nil];

谢谢!

Answer 1

好主意。这里是。就像警报 View 一样，只是添加了一个 block 属性，当警报被解除时会调用该属性。 (编辑 - 自原始答案以来我已经简化了这段代码。这是我现在在项目中使用的代码)

//  AlertView.h
//

#import <UIKit/UIKit.h>

@interface AlertView : UIAlertView

@property (copy, nonatomic) void (^completion)(BOOL, NSInteger);

- (id)initWithTitle:(NSString *)title message:(NSString *)message cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSArray *)otherButtonTitles;

@end

//
//  AlertView.m

#import "AlertView.h"

@interface AlertView () <UIAlertViewDelegate>

@end

@implementation AlertView

- (id)initWithTitle:(NSString *)title message:(NSString *)message cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSArray *)otherButtonTitles {

    self = [self initWithTitle:title message:message delegate:self cancelButtonTitle:cancelButtonTitle otherButtonTitles:nil];

    if (self) {
        for (NSString *buttonTitle in otherButtonTitles) {
            [self addButtonWithTitle:buttonTitle];
        }
    }
    return self;
}

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

    if (self.completion) {
        self.completion(buttonIndex==self.cancelButtonIndex, buttonIndex);
        self.completion = nil;
    }
}

@end

您可以扩展这个想法，为其他委托(delegate)方法提供 block ，但最常见的是 didDismiss。

这样调用它:

AlertView *alert = [[AlertView alloc] initWithTitle:@"Really Delete" message:@"Do you really want to delete everything?" cancelButtonTitle:@"Nevermind" otherButtonTitles:@[@"Yes"]];

alert.completion = ^(BOOL cancelled, NSInteger buttonIndex) {
    if (!cancelled) {
        [self deleteEverything];
    }
};
[alert show];