ios - viewDidDisappear 时布局被破坏

Question

我花了几天时间试图解决以下问题，但我没有得到任何结果:(

我有一个带有 UIScrollView 和一些 subview 的 viewController，我通过界面生成器添加其中一些，通过代码添加其他一些。当我调用推送下一个 viewController 的方法时，当前 View 会中断，并且当我弹出它时仍然会中断。

我尝试从 Storyboard 中删除自动布局设置，但仍然不起作用。

我以编程方式设置 View 的框架，并移动 ScrollView 的内容偏移量以制作动画。

我在 viewWillAppear 中调用此方法:

- (void)prepareQuestion
{
    int nextYposition;

    // Question
    NSString *q = [self.theQuestion getQuestionTextForLanguage:lang];
    NSString *badText = [self.theQuestion getInfTextForLanguage:lang];
    NSString *goodText = [self.theQuestion getSupTextForLanguage:lang];

    self.answer.questionID = self.theQuestion.questionID;

    if (whiteStyle) {
        question = [[NPSQuestionViewController alloc] initWithQuestion:q AndStyle:kNPSQuestionStyleWhite];
    } else {
        question = [[NPSQuestionViewController alloc] initWithQuestion:q AndStyle:kNPSQuestionStyleOther];
    }

    question.view.center = CGPointMake(self.view.center.x, self.view.center.y - 50);
    [self addChildViewController:question];
    [self.scrollView addSubview:question.view];

    nextYposition = question.view.frame.origin.y + question.view.frame.size.height;

    int questionHeight = 0; // Guardamos el alto dependiendo del tipo de control

    if (self.sliderStyle) {
        // Slider test
        if (whiteStyle) {
            NPSSliderViewControl = [[NPSSliderViewController alloc] initWithStyle:kNPSSliderViewStyleWhite];
        } else {
            NPSSliderViewControl = [[NPSSliderViewController alloc] initWithStyle:kNPSSliderViewStyleOther];
        }

        NPSSliderViewControl.iconSet = [[[OpinatManager sharedInstance] campanya] tipoIconos];
        [NPSSliderViewControl setBadText:badText andGoodText:goodText];
        [self addChildViewController:NPSSliderViewControl];
        [self.scrollView addSubview:NPSSliderViewControl.view];
        NPSSliderViewControl.delegate = self;

        CGRect frame = NPSSliderViewControl.view.frame;
        [NPSSliderViewControl.view setFrame:CGRectMake(0, nextYposition, frame.size.width, frame.size.height)];
        questionHeight = frame.size.height - 33; // 33 es el valor de la parte que desaparece del control

    } else {
        // Control
        if (whiteStyle) {
            NPSBtnViewControl = [[NPSBtnViewController alloc] initWithStyle:kNPSBtnViewStyleWhite];
        } else {
             NPSBtnViewControl = [[NPSBtnViewController alloc] initWithStyle:kNPSBtnViewStyleOther];
        }

        NPSBtnViewControl.iconSet = [[[OpinatManager sharedInstance] campanya] tipoIconos];
        [NPSBtnViewControl setBadText:badText andGoodText:goodText];
        [self addChildViewController:NPSBtnViewControl];
        [self.scrollView addSubview:NPSBtnViewControl.view];
        NPSBtnViewControl.delegate = self;

        CGRect frame = NPSBtnViewControl.view.frame;
        [NPSBtnViewControl.view setFrame:CGRectMake(0, nextYposition, frame.size.width, frame.size.height)];
        questionHeight = frame.size.height - 58; // 60 es el valor de la parte que desaparece del control
    }

    nextYposition += questionHeight;

    // Motives question
    if (whiteStyle) {
        motivesQuestion = [[NPSQuestionViewController alloc] initWithQuestion:self.insatisfactionTitle AndStyle:kNPSQuestionStyleWhite];
    } else {
        motivesQuestion = [[NPSQuestionViewController alloc] initWithQuestion:self.insatisfactionTitle AndStyle:kNPSQuestionStyleOther];
    }

    CGRect secondQuestionFrame = motivesQuestion.view.frame;
    secondQuestionFrame.origin.y = nextYposition;
    motivesQuestion.view.frame = secondQuestionFrame;
    motivesQuestion.view.alpha = 0;
    [self.scrollView addSubview:motivesQuestion.view];
    motivesQuestion.view.tag = 22;

    questionHeight = motivesQuestion.view.frame.size.height;

    nextYposition += questionHeight;

    // Setting up table Y position. Only works if I setted in viewDidAppear
    nextPosition = nextYposition;
    resetPosition = nextYposition;

    // Ajustamos la tableView
    self.tableMotives.alpha = 0;
}

有什么想法吗？谢谢!

Answer 1

如果您正在使用自动布局，您基本上不应该直接设置 View 框架。相反，您应该设置约束，以便所有内容都自动放置在正确的位置，并使用 @property 来保存对选定约束的“特殊”引用。这些“特殊”约束是控制屏幕上其他内容的整体位置的约束，它们通过 constant offset 来工作。 .

当您想执行一些动画来更改屏幕上所有内容的位置时，请使用 UIView 动画 block 并仅修改约束中的常量。

如果你想重置，再次修改约束上的常量。