objective-c - networkActivityIndi​​catorVisible 在 applicationDidBecomeActive 中是否有效？

Question

我正在尝试调用网络指示器，然后在此代码之后将其关闭，如下所示，但它没有显示在状态栏中。我究竟做错了什么？我认为这只是网络活动完成得很快，但即使在睡眠状态下它似乎也不起作用。

-(void)applicationDidBecomeActive:(UIApplication *)application {

UIImageView *loadingImage = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
loadingImage.image = [UIImage imageNamed:@"loading-splash.png"];
loadingImage.contentMode = UIViewContentModeCenter;
[self.window addSubview:loadingImage];


[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSData *dataURL =  [NSData dataWithContentsOfURL: [ NSURL URLWithString: @"http://mysite.tk/in-app/net.test" ]];
NSString *serverOutput = [[NSString alloc] initWithData:dataURL encoding: NSASCIIStringEncoding];
NSLog(@"%@", serverOutput);
sleep(1);
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    if([serverOutput isEqualToString:@"internet is working"])
    {
        [SVStatusHUD showWithImage:[UIImage imageNamed:@"connected.png"] status:@"Connected"];


    } else {

        UIAlertView *alertsuccess = [[UIAlertView alloc] initWithTitle:@"Connection Unsuccesful" message:@"App Requests has failed connecting to the server. Some or all of App Requests functions may not work. Please check your internet connection."
                                                              delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alertsuccess show];
        [alertsuccess release];

            }

[loadingImage release]; 
}

另外，如果有人想好心告诉我如何关闭图像视图，请随意，但我正要谷歌搜索。我是一个试图从教程等中学习的菜鸟。

Answer 1

您需要使用类似的方法在单独的线程中显示和隐藏指示器。

dispatch_async(dispatch_get_main_queue(), ^{
    // Put any code you want to execute in the main thread here.
});