ios - 如何居中 subview

Question

我正在将一个 UIViewController subview 添加到另一个 UIViewController。

效果很好。但是我很难尝试将 subview 居中放置在父 View 的中间。

我仔细阅读，发现有 2 行代码对其他人有用，但对我不起作用。

谁能指出我的问题？？

它们是:

popupController.view.center = [self.view convertPoint:self.view.center fromView:self.view.superview];

和

popupController.view.center = CGPointMake(self.view.bounds.size.width / 2, self.view.bounds.size.height / 2);

父 View Controller 代码:

- (IBAction)selectRoutine:(id)sender {
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];

    createRoutinePopupViewController* popupController = [storyboard instantiateViewControllerWithIdentifier:@"createRoutinePopupView"];
   // popupController.view.center = [self.view convertPoint:self.view.center fromView:self.view.superview];
    popupController.view.center = CGPointMake(self.view.bounds.size.width / 2, self.view.bounds.size.height / 2);

    //Tell the operating system the CreateRoutine view controller
    //is becoming a child:
    [self addChildViewController:popupController];

    //add the target frame to self's view:
    [self.view addSubview:popupController.view];

    //Tell the operating system the view controller has moved:
    [popupController didMoveToParentViewController:self];


}

子设置

Answer 1

似乎您在将 View Controller View 居中后重新定位了它。可能在 didMoveToParentViewController: 中。

将居中代码移到selectRoutine:方法的末尾

- (IBAction)selectRoutine:(id)sender
{
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];

    createRoutinePopupViewController* popupController = [storyboard instantiateViewControllerWithIdentifier:@"createRoutinePopupView"];

    [self addChildViewController:popupController];
    [self.view addSubview:popupController.view];
    [popupController didMoveToParentViewController:self];

    //do the centering here
    popupController.view.center = [self.view convertPoint:self.view.center fromView:self.view.superview];

}

或者更好的是，将其移动到 didMoveToParentViewController:

- (void)didMoveToParentViewController:(UIViewController *)parent
{
    //whatever code you have here

    self.view.center = self.view.superview.center;
}

您可能需要稍微修改一下这段代码。但我确定您的问题是居中代码的不正确(执行时间)放置 - 随后被其他一些 View 定位覆盖。