无法结束后台任务：不存在标识符为 1fd57580 的后台任务，或者它可能已经结束

Question

AppDelegate.m 文件包含

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    UIBackgroundTaskIdentifier taskID = [application beginBackgroundTaskWithExpirationHandler:^{
        [application endBackgroundTask:taskID];
    }];
}

我不知道为什么我在 gdb 中收到这条消息

Can't endBackgroundTask: no background task exists with identifier 1fd57580, or it may have already been ended. Break in UIApplicationEndBackgroundTaskError() to debug.

Answer 1

你的代码全错了。它应该是这样的：

UIBackgroundTaskIdentifier taskID = [application beginBackgroundTaskWithExpirationHandler:^{
    // Code to ensure your background processing stops executing
    // so it reaches the call to endBackgroundTask:
}];

// Put the code you want executed in the background here

if (taskID != UIBackgroundTaskInvalid) {
    [[UIApplication sharedApplication] endBackgroundTask:taskID];
}

Answer 2

如果您在后台使用位置更新，请在获取用户位置授权时添加以下代码。那是因为 Apple 将 allowsBackgroundLocationUpdates 的默认值从 iOS 9 开始更改为 NO。

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 9) {
    locationManager.allowsBackgroundLocationUpdates = YES;
}

无法结束后台任务：不存在标识符为 1fd57580 的后台任务，或者它可能已经结束

Can't endBackgroundTask: no background task exists with identifier 1fd57580, or it may have already been ended

ios

xcode6