UIView animateWithDuration：動畫：完成：應用轉換，而不是動畫

Question

試圖從KVO觀察中調用此消息。一旦圖片下載完成，這條消息就會發送出去。完成塊中的消息還包含可正常工作的動畫（正確動畫）。該動畫應用不帶動畫的轉換（等待動畫的長度，然後跳轉到最終狀態）。

/** 
* Discover the subview with the supplied tag, attach the fullsize image to the view 
* scale to fullsize and begin retract. 
* @param viewTag int - #FUTURE USE# - The tag of the view to be animated. 
* @param image UIImage - #FUTURE USE# - The image to be applied to the view. 
* @return void 
*/ 
- (void)animateViewWithTag:(int)viewTag andImage:(UIImage *)image { 

    Panel *activePanel = [self.panels objectAtIndex:currentIndex]; 
    UIView *activePanelView = [self.view viewWithTag:activePanel.panelId]; 

    // Display the transition to the fullsize version of the panel image. 
    // Determine the scale that needs to be applied to the view to show 
    // the image in the appropriate scaling. If scaled image is greater than 
    // the size of the screen, find the best fit. 

    float scale = image.size.width/activePanelView.frame.size.width; 

    if (image.size.width > self.view.window.frame.size.width || image.size.height > self.view.window.frame.size.height) { 
     // The image will scale beyond the bounds of the window, scale must be adjusted. 
     scale = self.view.window.frame.size.width/activePanelView.frame.size.width; 
    } 

    CGAffineTransform transform = CGAffineTransformMakeScale(scale, scale); 

    [UIView animateWithDuration:1.0 
        animations:^{ 
         // Get the fullsize image and display it in the growing panel. 
         [activePanelView setTransform:transform]; 
         [NSThread sleepForTimeInterval:3.0]; 
        } 
        completion:^(BOOL finished) { 
         [self retractImage:activePanelView]; 
        }]; 
} 


#pragma mark - KVO 

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {  
    int tmpInt = (int)context;   
    UIImage *tmpImage = [change objectForKey:NSKeyValueChangeNewKey]; 

    if (keyPath == @"imgOriginal") { 
     [self animateViewWithTag:[(Panel *)object panelId] andImage:tmpImage];    
    } 

} 

Answer 1

線程睡眠的目的是什麼？

如果你讓主線程睡眠，那麼它不會在此期間更新動畫。

如果你不在主線程上調用它，那麼它也不會工作，因爲UIKit動畫不是線程安全的，只能從主線程可靠地使用。