如何实现微信等navigationbar加上UIActivityIndicatorView

定义一个 父类vc ，然所有子vc全都继承，
在父类vc中 添加如上代码坚定AFN的两个代理方法即可,如果网络连接非afn ,可以用相同的方式发送通知 即可

- (void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:YES];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkRequestDidStart) name:AFNetworkingOperationDidStartNotification object:nil];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkRequestDidFinish) name:AFNetworkingOperationDidFinishNotification object:nil];}- (void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:YES];    [[NSNotificationCenter defaultCenter] removeObserver:self name:AFNetworkingOperationDidStartNotification object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self name:AFNetworkingOperationDidFinishNotification object:nil];}#pragma mark#pragma mark Notification- (void)networkRequestDidStart{    DLog(@"网络开始连接");//    if([self.netTitleString isEqualToString:@"self.title"])//    {//        self.netTitleString = [self.title copy];//    }//    self.navigationItem.titleView = self.navActiveView;//    self.navActiveView.titleLabel.text = self.title;//    [self.navActiveView.activeView startAnimating];}- (void)networkRequestDidFinish{    DLog(@"网络连接结束");//    self.title = [self.netTitleString copy];//    self.navigationItem.titleView = nil;}