当应用程序从后台返回前台时，MCSession ofen无法重新连接

Question

我正在使用Mutipeer Connectivity制作聊天应用。起初，一切运行良好，MCSession可以相互连接。但是，当用户点击主页按钮然后点按应用程序图标时，应用程序会相互断开连接，并且通常无法重新连接。但有时它可以重新连接。成功是随机的。

    - (void)viewDidLoad
{
    [super viewDidLoad];
    ...

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(DidBecomeActive:)
                                                 name: UIApplicationDidBecomeActiveNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(didEnterBackground:)
                                                 name: UIApplicationDidEnterBackgroundNotification object:nil];

    NSString *displayname=[[NSUUID UUID] UUIDString];
    _MyPeerID=[[MCPeerID alloc] initWithDisplayName:displayname];

}

- (void)DidBecomeActive:(NSNotification *)notification
{

    if (notFirstLaunch==YES) {
        NSLog(@"DidBecomeActive");
        NSString *displayname=[[NSUUID UUID] UUIDString];
        _MyPeerID=[[MCPeerID alloc] initWithDisplayName:displayname];
        [self createSession];
        [self createAdvertiser];
        [self beginBrowsing];


    }
    notFirstLaunch=YES;

}

- (void)didEnterBackground:(NSNotification *)notification
{
    NSLog(@"didEnterBackground");
    [_MySession disconnect];
    _MySession=nil;
    _MyBrowser=nil;
    _MyAdver=nil;


}



- (void)createSession
{
    _MySession=[[MCSession alloc] initWithPeer:_MyPeerID];
    _MySession.delegate=self;
}


- (void)createAdvertiser
{
    _MyAdver=[[MCNearbyServiceAdvertiser alloc] initWithPeer:_MyPeerID discoveryInfo:nil serviceType:MyServiceType];
    _MyAdver.delegate=self;
    [_MyAdver startAdvertisingPeer];
}

- (void)beginBrowsing {
    _MyBrowser=[[MCNearbyServiceBrowser alloc] initWithPeer:_MyPeerID serviceType:MyServiceType];
    _MyBrowser.delegate=self;
    [_MyBrowser startBrowsingForPeers];
}

Answer 1

根据您发布的代码判断，没有重新连接，因为在didEnterBackground中，您断开与会话的连接并破坏会话，浏览器和广告商。在DidBecomeActive中，您有一个警卫（notFirstLaunch），这意味着会话和广告商只在您第一次活动时创建，而不是在您从后台回来后变为活动状态。