在显示远程通知期间应用程序崩溃

Question

如果应用程序在前台收到通知，并试图显示使用Toast的横幅。

简单的情况下工作正常，没有出现任何问题..

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo { 
    UIView *parentView = [UIApplication sharedApplication].keyWindow.rootViewController.view; 
    [parentView makeToast:@"toast"]; 
} 

但是当我试图表明我自己的自定义视图，我上showToast方法不好EXC_BAD_ACCESS错误：

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo { 
    UIView *bannerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.topController.view.frame.size.width, 80)]; 
    UIView *parentView = [UIApplication sharedApplication].keyWindow.rootViewController.view; 
    bannerView.backgroundColor = [UIColor redColor]; 
    [parentView showToast: bannerView duration:3.0 position:CSToastPositionTop completion:nil]; 
} 

是- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo方法是编程这种类型的行为的危险地点？有一个强烈的参考parentView似乎并没有工作，我怎样才能确定哪个对象越来越过分？

Answer 1

您可以直接在appdelegate窗口（该窗口位于所有视图的顶层）上直接显示烤面包，而不是获取目前可见的父视图。

-(void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo 
{ 


    if (application.applicationState == UIApplicationStateActive) 
    { 
     [self.window makeToast:@"This is a piece of toast."]; 
    } 
}