Question

我可以使用什么样的入门代码制作一个简单的UIAlertView，上面有一个“OK”按钮？

Answer 1

当您想要显示警报时，请执行以下操作：

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"ROFL" 
                                                    message:@"Dee dee doo doo." 
                                                    delegate:self 
                                                    cancelButtonTitle:@"OK" 
                                                    otherButtonTitles:nil];
[alert show];

    // If you're not using ARC, you will need to release the alert view.
    // [alert release];

如果您想在单击按钮时执行某些操作，请实现此委托方法：

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    // the user clicked OK
    if (buttonIndex == 0) {
        // do something here...
    }
}

确保您的代理符合UIAlertViewDelegate协议：

@interface YourViewController : UIViewController <UIAlertViewDelegate>

Answer 2

其他答案已经提供了适用于iOS 7及更早版本的信息，但在iOS 8中已弃用 UIAlertView 。

在iOS 8+中，您应该使用UIAlertController。它是UIAlertView和UIActionSheet的替代品。文档：UIAlertController Class Reference。关于NSHipster的一篇很好的文章。

要创建简单的警报视图，您可以执行以下操作：

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title"
                                                                         message:@"Message"
                                                                  preferredStyle:UIAlertControllerStyleAlert];
//We add buttons to the alert controller by creating UIAlertActions:
UIAlertAction *actionOk = [UIAlertAction actionWithTitle:@"Ok"
                                                   style:UIAlertActionStyleDefault
                                                 handler:nil]; //You can use a block here to handle a press on this button
[alertController addAction:actionOk];
[self presentViewController:alertController animated:YES completion:nil];

Swift 3/4：

let alertController = UIAlertController(title: "Title", message: "Message", preferredStyle: .alert)
//We add buttons to the alert controller by creating UIAlertActions:
let actionOk = UIAlertAction(title: "OK",
    style: .default,
    handler: nil) //You can use a block here to handle a press on this button

alertController.addAction(actionOk)

self.present(alertController, animated: true, completion: nil)

请注意，由于它是在iOS 8中添加的，因此该代码无法在iOS 7及更早版本上运行。所以，遗憾的是，现在我们必须使用这样的版本检查：

NSString *alertTitle = @"Title";
NSString *alertMessage = @"Message";
NSString *alertOkButtonText = @"Ok";

if ([UIAlertController class] == nil) { //[UIAlertController class] returns nil on iOS 7 and older. You can use whatever method you want to check that the system version is iOS 8+
// Starting with Xcode 9, you can also use 
// if (@available(iOS 8, *)) {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:alertTitle
                                                        message:alertMessage
                                                       delegate:nil
                                              cancelButtonTitle:nil
                                              otherButtonTitles:alertOkButtonText, nil];
    [alertView show];
}
else {
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:alertTitle
                                                                             message:alertMessage
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    //We add buttons to the alert controller by creating UIAlertActions:
    UIAlertAction *actionOk = [UIAlertAction actionWithTitle:alertOkButtonText
                                                       style:UIAlertActionStyleDefault
                                                     handler:nil]; //You can use a block here to handle a press on this button
    [alertController addAction:actionOk];
    [self presentViewController:alertController animated:YES completion:nil];
}

Swift 3/4：

let alertTitle = "Title"
let alertMessage = "Message"
let alertOkButtonText = "Ok"

if #available(iOS 8, *) {
    let alertController = UIAlertController(title: alertTitle, message: alertMessage, preferredStyle: .alert)
    //We add buttons to the alert controller by creating UIAlertActions:
    let actionOk = UIAlertAction(title: alertOkButtonText,
        style: .default,
        handler: nil) //You can use a block here to handle a press on this button

    alertController.addAction(actionOk)
}
else {
    let alertView = UIAlertView(title: alertTitle, message: alertMessage, delegate: nil, cancelButtonTitle: nil, otherButtonTitles: alertOkButtonText)
    alertView.show()
}

UPD：针对Swift 3/4进行了更新。

UPD 2：从Xcode 9开始，在Objc-C中添加了@available的注释。

Answer 3

UIAlertView在iOS 8上已弃用。因此，要在iOS 8及更高版本上创建警报，建议使用UIAlertController：

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Title" message:@"Alert Message" preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *defaultAction = [UIAlertAction actionWithTitle:@"Ok" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){

    // Enter code here
}];
[alert addAction:defaultAction];

// Present action where needed
[self presentViewController:alert animated:YES completion:nil];

这就是我实施它的方式。

Answer 4

UIAlertView *alert = [[UIAlertView alloc]
 initWithTitle:@"Title" 
 message:@"Message" 
 delegate:nil //or self
 cancelButtonTitle:@"OK"
 otherButtonTitles:nil];

 [alert show];
 [alert autorelease];

Answer 5

作为前两个答案（用户“sudo rm -rf”和“Evan Mulawski”）的补充，如果您在单击警报视图时不想执行任何操作，则可以分配，显示和释放它。您不必声明委托协议。

Answer 6

UIAlertView *myAlert = [[UIAlertView alloc] 
                         initWithTitle:@"Title"
                         message:@"Message"
                         delegate:self
                         cancelButtonTitle:@"Cancel"
                         otherButtonTitles:@"Ok",nil];
[myAlert show];

Answer 7

这是一个完整的方法，只有一个按钮，一个'ok'，关闭UIAlert：

- (void) myAlert: (NSString*)errorMessage
{
    UIAlertView *myAlert = [[UIAlertView alloc]
                          initWithTitle:errorMessage
                          message:@""
                          delegate:self
                          cancelButtonTitle:nil
                          otherButtonTitles:@"ok", nil];
    myAlert.cancelButtonIndex = -1;
    [myAlert setTag:1000];
    [myAlert show];
}

Answer 8

This page显示了如果使用Swift，如何添加UIAlertController。

Answer 9

使用数组数据进行简单警报：

NSString *name = [[YourArray objectAtIndex:indexPath.row ]valueForKey:@"Name"];

NSString *msg = [[YourArray objectAtIndex:indexPath.row ]valueForKey:@"message"];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:name
                                                message:msg
                                               delegate:self
                                      cancelButtonTitle:@"OK"
                                      otherButtonTitles:nil];
[alert show];

Answer 10

对于Swift 3：

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)

添加一个简单的UIAlertView

10 个答案: