SpriteKit :为什么我不能隐藏SKSprite节点，然后截图呢？

Question

这可能是一个愚蠢的问题，但是为什么当我执行隐藏按钮时，屏幕截图会发生在隐藏按钮之前？是否有办法确保按钮在屏幕截图发生前就消失了？我需要单独的线程调用吗？谢谢!

if([node.name isEqualToString:@"ScreenshotButton"])
{
    [self UserHideAllButtons];   //This hides all menus and buttons
    [self captureFullScreen];  This takes a screenshot and sends it to camera 
    roll
}

-(void)UserHideAllButtons
{
    [self showItem:-1 withItemNamed:btnCandy];
    [self showItem:-1 withItemNamed:btnCharacter];
    [self showItem:-1 withItemNamed:btnDecor];
    [self showItem:-1 withItemNamed:btnGifts];
    [self showItem:-1 withItemNamed:btnGreeting];

    [self showItem:-1 withItemNamed:btnCandyPressed];
    [self showItem:-1 withItemNamed:btnCharacter];
    [self showItem:-1 withItemNamed:btnDecorPressed];
    [self showItem:-1 withItemNamed:btnGiftsPressed];
    [self showItem:-1 withItemNamed:btnGreetingPressed];



    [self hideObjects:-1 withArrayNamed:candyObjects];
    [self hideObjects:-1 withArrayNamed:characterObjects];
    [self hideObjects:-1 withArrayNamed:decorObjects];
    [self hideObjects:-1 withArrayNamed:giftsObjects];
    [self hideObjects:-1 withArrayNamed:greetingObjects];

    [self clearMenu];
    sliderArrowBtn.zPosition=-1;
    sliderMenu.zPosition=-1;
    slider.zPosition=-1;
    selectedItemBack.zPosition=-1;
}

-(UIImage *)captureFullScreen
{
    AppDelegate *_appDelegate = (AppDelegate *)[UIApplicationsharedApplication].delegate;

    // if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
    // for retina-display
    UIGraphicsBeginImageContextWithOptions(_appDelegate.window.bounds.size, NO, [UIScreen
    mainScreen].scale);
    [_appDelegate.window drawViewHierarchyInRect:_appDelegate.window.bounds 
    afterScreenUpdates:NO];
     screenshot= UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Photo Saved To Camera Roll"
                                                    message:@""
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];

    screenshot=[self centerCropImage:screenshot];

    UIImageWriteToSavedPhotosAlbum(screenshot, nil, nil, nil); //if you need to save
    [alert show];
    return screenshot;
}

Answer 1

最可能的原因是，在更新同一帧时，您会同时隐藏和截图。因此，您实际采取的屏幕截图是当前显示的框架的屏幕内容，它不会显示类似隐藏按钮的任何更改，直到Sprite Kit在更新/操作/物理循环结束时重新呈现屏幕。

您将不得不等待一个框架，以便雪碧套件呈现的场景与按钮删除，然后你可以再次显示按钮。请注意，这将不可避免地导致按钮闪烁。

要等待一个框架，只需运行runBlock操作就足够了：

[self runAction:[SKAction runBlock:^{
    UIImage* screenshot = [self captureFullScreen];
}];

如果不够，请在didEvaluateActions或didSimulatePhysics中运行该操作，以确保该操作计划运行下一个框架。