【读书笔记】GCD-block-后台运行

#import <UIKit/UIKit.h>@interface AppDelegate : UIResponder <UIapplicationDelegate>@PRoperty (strong, nonatomic) UIWindow *window;//后台长久运行@property (assign, nonatomic) UIBackgroundTaskIdentifier backgroundUpdateTask;@end

//当app进入后台的时候- (void)applicationDidEnterBackground:(UIApplication *)application {    [self beingBackgroundUpdateTask];    //需要长久运行的代码    [self endBackgroundUpdateTask];}#pragma -mark -functions- (void)beingBackgroundUpdateTask{    self.backgroundUpdateTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{        [self endBackgroundUpdateTask];    }];}- (void)endBackgroundUpdateTask{    [[UIApplication sharedApplication] endBackgroundTask: self.backgroundUpdateTask];    self.backgroundUpdateTask = UIBackgroundTaskInvalid;}