iOS开发之后台保持socket的连接

最近新开一个项目，要使用UDP通讯来和智能设备进行数据传输。大家都知道，在iOS平台上，由于苹果的后台机制，会有以下问题：

  1. 当程序退到后台的时候，一段时间后（大概300s）所有线程被挂起。
  2. 线程挂起后，系统就会回收所有的socket资源，那么socket连接就会被关闭，因此无法再进行数据的传输。

解决方案：

1.

　　　　

2.在AppDelegate中：　　　　

1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
2 {    
3     //socket心跳包
4     NSTimer *socketTimer = [NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(socketTimer) userInfo:nil repeats:YES];
5     [[NSRunLoop mainRunLoop] addTimer:socketTimer forMode:NSRunLoopCommonModes];
6     return YES;
7 }

 

1 //socket心跳包
2 - (void)socketTimer
3 {
4     [[NSNotificationCenter defaultCenter] postNotificationName:@"SOCKETTIMER" object:nil];//计时器内周期性去调用socket心跳包，保持连接。
5 }

 

 1 - (void)applicationDidEnterBackground:(UIApplication *)application
 2 {
 3     // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
 4     // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
 5     
 6     [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];//开启后台任务
 7     
 8 }
 9 
10 
11 - (void)applicationWillEnterForeground:(UIApplication *)application
12 {
13     // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
14     [[UIApplication sharedApplication] endBackgroundTask:UIBackgroundTaskInvalid];//结束后台任务
15 }

注意：经测试使用以上方法在App上架时会被苹果审核组拒绝。

2019年8月22日加入以上代码段发布，依旧被拒绝。

 修改方案（换一种后台运行方法：）【可以审核通过✅】

 

 

AppDelegate.m

 

 

@interface AppDelegate ()
{
    UIBackgroundTaskIdentifier _backIden;
}
@property (nonatomic, assign) NSInteger number;
@property (nonatomic, strong) NSTimer   *timer;

@end

 

　　

/// 退到后台
- (void)applicationDidEnterBackground:(UIApplication *)application {
    [self beginTask];
    [UIApplication sharedApplication].applicationIconBadgeNumber = 0;
    self.number = 0;
    if (@available(iOS 10.0, *)) {
        self.timer = [NSTimer scheduledTimerWithTimeInterval:1.f repeats:YES block:^(NSTimer * _Nonnull timer) {
            self.number++;
            [UIApplication sharedApplication].applicationIconBadgeNumber = self.number;
            if (self.number == 9) {
                [self.timer invalidate];
            }
            NSLog(@"%@==%ld ",[NSDate date],(long)self.number);
        }];
    } else {
        // Fallback on earlier versions
    }
}

/// app进入后台后保持运行
- (void)beginTask {
    _backIden = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
        //如果在系统规定时间3分钟内任务还没有完成，在时间到之前会调用到这个方法
        [self endBack];
    }];
}

/// 结束后台运行，让app挂起
- (void)endBack {
    //切记endBackgroundTask要和beginBackgroundTaskWithExpirationHandler成对出现
    [[UIApplication sharedApplication] endBackgroundTask:_backIden];
    _backIden = UIBackgroundTaskInvalid;
}

　　

 

posted @ 2017-04-13 16:58  isHakan  阅读(8268)  评论(3)  编辑  收藏  举报