Question

我使用以下代码来点击图片视图并导航到另一个视图控制器：

-(void)tapDetected:(UIGestureRecognizer *)recognizer{

    [MBProgressHUD showHUDAddedTo:self.view animated:YES];

    NSLog(@"single Tap on imageview");

    ImageTapGesture *sender = (ImageTapGesture *)recognizer;

    UIStoryboard * storyboard = self.storyboard;

    tele * detail = [storyboard instantiateViewControllerWithIdentifier: @ "teledramaView"];

    detail.imagelink = sender.imageLink;

    detail.description = sender.description;

    detail.id = sender.id;

    [self.navigationController pushViewController: detail animated: YES];

    [MBProgressHUD hideHUDForView:self.view animated:YES];
}

到目前为止，代码工作正常，但问题是进度条无法正常显示。

它会在转到其他控制器之前的最后时刻显示，但日志出现在进度条之前：NSLog(@"single Tap on imageview");

有人可以告诉我为什么进度条不能正常工作吗？谢谢。

Answer 1

答案很简单，因为您在同一个线程中显示并隐藏了progressHUD，它会在添加后立即删除。由于您在主线程上执行了方法，这也是处理任何UI更改的方法，因此只有在方法结束后才会添加progressHUD。但是，由于你删除了最后一行的progressHUD，它也将被直接删除。更糟糕的是，添加和删除HUD之间的任何代码都会阻止任何UI更改。

您需要稍微延迟加载，以便系统有时间显示progressHUD：

-(void)tapDetected:(UIGestureRecognizer *)recognizer{
[MBProgressHUD showHUDAddedTo:self.view animated:YES];

NSLog(@"single Tap on imageview");

[self performSelector:@selector(navigateToDetailView:) withObject:recognizer afterDelay:0.0];

}

-(void) navigateToDetailView:(UIGestureRecognizer*)recognizer{
    ImageTapGesture *sender = (ImageTapGesture *)recognizer;

    UIStoryboard * storyboard = self.storyboard;

    tele * detail = [storyboard instantiateViewControllerWithIdentifier: @ "teledramaView"];
    detail.imagelink = sender.imageLink;
    detail.description = sender.description;
    detail.id = sender.id;

    [self.navigationController pushViewController: detail animated: YES];

    [MBProgressHUD hideHUDForView:self.view animated:YES];
}

进度条没有显示ios

1 个答案: