Question

我有一个Obj C应用程序，其中AppDelegate包含一个切换UIAlertController的方法（一个＆＃39;正在加载＆＃39;没有OK / Cancel按钮的警报）。显示警报工作，但隐藏不。有人可以建议吗？

-(void)toggleAlert(show){
    UIViewController *vc = self.window.rootViewController;

    if (show) {
        // Show alert
        [vc presentViewController:self.loadingAlert animated:YES completion:nil];

    } else {
        // Hide alert
        [self.loadingAlert dismissViewControllerAnimated:YES completion:nil];
    }
}

Answer 1

用

替换隐藏线

[self dismissViewControllerAnimated:YES completion:nil];

Generally the parent view controller is responsible for dismissing the modally presented view controller(your popup)

Answer 2

您需要在appDelegate中发送当前的ViewController，并且需要向其发送警报。

<强> AppDelegate.h

@property (strong, nonatomic)UIAlertController * alert;
-(void)showAlert:(NSString *)strMessage viewController:(UIViewController*)VC;

<强> AppDelegate.m

-(void)showAlert:(NSString *)strMessage viewController:(UIViewController*)VC{
    _alert = [UIAlertController
                                 alertControllerWithTitle:@"Title"
                                 message:strMessage
                                 preferredStyle:UIAlertControllerStyleAlert];

    //Add Buttons

    UIAlertAction* yesButton = [UIAlertAction
                                actionWithTitle:@"Yes"
                                style:UIAlertActionStyleDefault
                                handler:^(UIAlertAction * action) {
                                    //Handle your yes please button action here

                                }];

    UIAlertAction* noButton = [UIAlertAction
                               actionWithTitle:@"Cancel"
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction * action) {
                                   //Handle no, thanks button
                               }];

    //Add your buttons to alert controller

    [_alert addAction:yesButton];
    [_alert addAction:noButton];

    [VC presentViewController:_alert animated:YES completion:nil];

}

如果您想在某个时间以编程方式隐藏此提醒，请使用以下方法：

-(void)hideAlert
{
    [_alert dismissViewControllerAnimated:YES completion:^{

    }];
}

Answer 3

您可以使用此类别

#import "UIAlertController+Window.h"
#import <objc/runtime.h>

@interface UIAlertController (Window)

- (void)show;
- (void)show:(BOOL)animated;

@end

@interface UIAlertController (Private)

@property (nonatomic, strong) UIWindow *alertWindow;

@end

@implementation UIAlertController (Private)

@dynamic alertWindow;

- (void)setAlertWindow:(UIWindow *)alertWindow {
    objc_setAssociatedObject(self, @selector(alertWindow), alertWindow, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIWindow *)alertWindow {
    return objc_getAssociatedObject(self, @selector(alertWindow));
}

@end

@implementation UIAlertController (Window)

- (void)show {
    [self show:YES];
}

- (void)show:(BOOL)animated {
    self.alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    self.alertWindow.rootViewController = [[UIViewController alloc] init];

    id<UIApplicationDelegate> delegate = [UIApplication sharedApplication].delegate;
    // Applications that does not load with UIMainStoryboardFile might not have a window property:
    if ([delegate respondsToSelector:@selector(window)]) {
        // we inherit the main window's tintColor
        self.alertWindow.tintColor = delegate.window.tintColor;
    }

    // window level is above the top window (this makes the alert, if it's a sheet, show over the keyboard)
    UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject;
    self.alertWindow.windowLevel = topWindow.windowLevel + 1;

    [self.alertWindow makeKeyAndVisible];
    [self.alertWindow.rootViewController presentViewController:self animated:animated completion:nil];
}

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

    // precaution to insure window gets destroyed
    self.alertWindow.hidden = YES;
    self.alertWindow = nil;
}

@end

样本用法：

// need local variable for TextField to prevent retain cycle of Alert otherwise UIWindow
// would not disappear after the Alert was dismissed
__block UITextField *localTextField;
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Global Alert" message:@"Enter some text" preferredStyle:UIAlertControllerStyleAlert];
[alert addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
    NSLog(@"do something with text:%@", localTextField.text);
// do NOT use alert.textfields or otherwise reference the alert in the block. Will cause retain cycle
}]];
[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
    localTextField = textField;
}];
[alert show];

Answer 4

试试这个：

AlertViewController和ActionSheet的解决方案

-(void)showAlertWithMessage:(NSString *)message WithTitle:(NSString *)title WithCancelButtonTitle:(NSString *)cancelTitle WithAnotherButtonTitle:(NSString *)anotherTitle WithAlertStyle:(UIAlertControllerStyle)alertStyle WithCallBack:(void(^) (BOOL isConfirm))alertCallback{

        UIAlertController * alert = [UIAlertController
                                     alertControllerWithTitle:Localization(title)
                                     message:Localization(message)
                                     preferredStyle:alertStyle];
        if (anotherTitle){
            UIAlertAction* yesButton = [UIAlertAction
                                        actionWithTitle:Localization(anotherTitle)
                                        style:UIAlertActionStyleDefault
                                        handler:^(UIAlertAction * action) {
                                            [alert dismissViewControllerAnimated:YES completion:nil];
                                            if (alertCallback) {
                                                alertCallback(YES);
                                            }

                                        }];
            [alert addAction:yesButton];

        }


        if (cancelTitle) {
            UIAlertAction* cancelButton = [UIAlertAction
                                           actionWithTitle:Localization(cancelTitle)
                                           style:UIAlertActionStyleCancel
                                           handler:^(UIAlertAction * action) {
                                               [alert dismissViewControllerAnimated:YES completion:nil];
                                               if (alertCallback) {
                                                   alertCallback(NO);
                                               }
                                           }];
            [alert addAction:cancelButton];

        }


        UIViewController *vc = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
        [[vc presentedViewController] ? vc.presentedViewController : vc presentViewController:alert animated:YES completion:^{
        }];

}

<强>调用

 [appDelegateIntsance showAlertWithMessage:message WithTitle:title WithCancelButtonTitle:@"Cancel" WithAnotherButtonTitle:@"OK" WithAlertStyle:UIAlertControllerStyleAlert WithCallBack:^(BOOL isConfirm) {
        // handal you click event here
    }];

从AppDelegate显示/隐藏UIAlertController

4 个答案: