ios - UIPopoverPresentationController 淡入

Question

在我的 iOS8+ 项目中，我使用 UIPopoverPresentationController 呈现一个 UIViewController:

vc.modalPresentationStyle = UIModalPresentationPopover;
vc.popoverPresentationController.delegate = self;
vc.popoverPresentationController.sourceView = self.someView.superview;
vc.popoverPresentationController.sourceRect = self.someView.frame;
vc.popoverPresentationController.backgroundColor = [UIColor clearColor];
vc.popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirectionUp | UIPopoverArrowDirectionDown;
vc.preferredContentSize = CGSizeMake(200, 500);

(同时实现委托(delegate)方法强制弹出)

-(UIModalPresentationStyle)adaptivePresentationStyleForPresentationController:(UIPresentationController *)controller
{
    return UIModalPresentationNone;
}

目前，它会立即出现在呈现的 UIViewController 上方(并随着淡出而消失)。谁能指导我自定义此演示文稿，使其淡入？

Answer 1

我可以通过简单的设置来达到效果:

[self.view setAlpha: 0.0];
[self.popoverPresentationController.containerView setAlpha:0.0];

在popover viewController的viewWillAppear:方法中，然后调用

[UIView animateWithDuration:0.25 delay:0.0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{

    [self.view setAlpha:1.0];
    [self.popoverPresentationController.containerView setAlpha:1.0];

} completion:nil];

在 viewDidAppear: 方法中。