ios - 从viewWillLayoutSubviews移到viewDidLoad后， View 未显示

我一直在试图自学Objective-C，但是我在观点方面遇到了麻烦。

将所有内容从viewWillLayoutSubviews移到viewDidLoad后，我的场景不再显示。 MyScene.m中的代码正在运行，我只是看不到它。我在这里缺少一些明显的缺陷吗？

前面的viewWillLayoutSubviews方法在下面可用。此处的所有内容都直接切成viewDidLoad，不包括[super viewDidLayoutSubviews]。

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];

    SKView * skView = (SKView *)self.view;
    if (!skView.scene)
    {
        skView.showsFPS = YES;
        skView.showsNodeCount = YES;

        SKScene * scene = [MyScene sceneWithSize:skView.bounds.size];
        scene = [MyScene sceneWithSize:skView.bounds.size];
        scene.scaleMode = SKSceneScaleModeAspectFill;

        [skView presentScene:scene];
    }

    UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:(scene) action:@selector(screenSwipedRight)];
    swipeRight.numberOfTouchesRequired = 1;
    swipeRight.direction=UISwipeGestureRecognizerDirectionRight;
    [self.view addGestureRecognizer:(swipeRight)];

    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:(scene) action:@selector(screenSwipedLeft)];
    swipeLeft.numberOfTouchesRequired = 1;
    swipeLeft.direction=UISwipeGestureRecognizerDirectionLeft;
    [self.view addGestureRecognizer:(swipeLeft)];

    UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizer alloc] initWithTarget:(scene) action:@selector(screenSwipedUp)];
    swipeUp.numberOfTouchesRequired = 1;
    swipeUp.direction=UISwipeGestureRecognizerDirectionUp;
    [self.view addGestureRecognizer:(swipeUp)];

}

如果有帮助，我将所有内容从viewWillLayoutSubviews移到viewDidLoad，以避免每次视图旋转时重新创建手势识别器。

谢谢你的帮助!

最佳答案

你为什么这么做？可接受的初始化SKScene的方法在viewWillLayoutSubviews中。

只需在!skView.scene块内创建手势识别器即可:

if (!skView.scene)
{
    // init everything here that should be initialized only once
    // AND should not re-run every time the view rotates
}

就这么简单。

关于ios - 从viewWillLayoutSubviews移到viewDidLoad后， View 未显示，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/20925897/