進步黨欄不顯示IOS

Question

我用下面的代碼來獲取圖像視圖水龍頭，然後導航到另一個視圖控制器：

-(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]; 
} 

到目前爲止，代碼工作正常，但問題是進度條不正確顯示。

這表明在臨睡前其他控制器的最後時刻，但日誌而來的進度條前：NSLog(@"single Tap on imageview");

任何人能告訴我，爲什麼，因爲它是指工作進度條不工作？謝謝。

Answer 1

那麼答案很簡單，因爲您在同一個線程中顯示和隱藏progressHUD，只要添加它就會被刪除。由於您的方法是在主線程上執行的，這也是處理任何UI更改，您的progressHUD只會在方法結束後添加。但是，由於您在最後一行刪除了progressHUD，它也將被直接刪除。更糟糕的是，添加和刪除HUD之間的任何代碼都會阻止任何UI更改。

您需要延遲加載了一下，給系統時間呈現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]; 
}