使用 UIAlertController 的 AlertViews

UIAlertView 和 UIActionSheet 在 iOS 8 和 Later 中被弃用。因此，Apple 为 AlertView 和 ActionSheet 推出了一款名为 UIAlertController 的新控制器，改变了 preferredStyle，你可以在 AlertView 和 ActionSheet 之间切换。没有委托方法，因为所有按钮事件都在其块中处理。

简单的 AlertView

迅速：

let alert = UIAlertController(title: "Simple", message: "Simple alertView demo with Cancel and OK.", preferredStyle: .alert)

alert.addAction(UIAlertAction(title: "Cancel", style: .cancel) { _ in
        print("Cancel")
})
alert.addAction(UIAlertAction(title: "OK", style: .default) { _ in
        print("OK")
})

present(alert, animated: true)

Objective-C 的：

 UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Simple" message:@"Simple alertView demo with Cancel and OK." preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * action) {
        NSLog(@"Cancel");
    }];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
        NSLog(@"OK");
    }];
    
    [alertController addAction:cancelAction];
    [alertController addAction:okAction];
    [self presentViewController:alertController animated: YES completion: nil];

破坏性警报视图

迅速：

let alert = UIAlertController(title: "Simple", message: "Simple alertView demo with Cancel and OK.", preferredStyle: .alert)

alert.addAction(UIAlertAction(title: "Destructive", style: .destructive) { _ in
        print("Destructive")
})
alert.addAction(UIAlertAction(title: "OK", style: .default) { _ in
        print("OK")
})

present(alert, animated: true)

Objective-C 的：

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Destructive" message:@"Simple alertView demo with Destructive and OK." preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *destructiveAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * action) {
        NSLog(@"Destructive");
    }];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
        NSLog(@"OK");
    }];
    
    [alertController addAction:destructiveAction];
    [alertController addAction:okAction];
    [self presentViewController:alertController animated: YES completion: nil];