Question

UITextView是模态控制器视图的子视图。我需要在键盘出现时降低UITextView高度，以使UITextView的底部边框y坐标等于键盘的顶部y坐标。我想要键盘高度

CGRect frameBegin = [[notification.userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] ;
CGRect frameEnd = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

CGRect resultBegin = [self.view convertRect:frameBegin fromView:nil];
CGRect resultEnd = [self.view convertRect:frameEnd fromView:nil];

CGFloat kbdHeight = resultBegin.origin.y  - resultEnd.origin.y;

问题是当键盘出现时，此模态视图会跳起来。在这种情况下如何计算键盘的顶部边框坐标？

Answer 1

你可以这样做：

1. Register for keyboard notifications:

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(myTextViewHeightAdjustMethod:)
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(myTextViewHeightAdjustMethod:)
                                             name:UIKeyboardDidShowNotification
                                           object:nil];

2. Calculate intersection and adjust textView height with the bottom constraint

    - (void)myTextViewHeightAdjustMethod:(NSNotification *)notification
    {
        NSDictionary *userInfo = [notification userInfo];
        CGRect keyboardFinalFrame = [[userInfo emf_ObjectOrNilForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

        CGPoint keyboardOriginInView = [self.view convertPoint:keyboardFinalFrame.origin fromView:nil];

             CGFloat intersectionY = CGRectGetMaxY(self.view.frame) - keyboardOriginInView.y;

             if (intersectionY >= 0)
             {
                 self.textViewBottomConstraint.constant = intersectionY + originalTextViewBottomConstraint;

                 [self.textView setNeedsLayout];
    }

请记得取消注册通知。

Answer 2

如果您不需要自己编写代码，我建议您使用https://github.com/hackiftekhar/IQKeyboardManager

它很棒（对我来说，到目前为止），你需要做的就是导入它并在AppDelegate中添加这一行代码：

let assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: self.player.currentItem!.asset)
        assetImgGenerate.appliesPreferredTrackTransform = true
        assetImgGenerate.requestedTimeToleranceAfter = kCMTimeZero;
        assetImgGenerate.requestedTimeToleranceBefore = kCMTimeZero;
        let t : CMTime!
  let videoLengthInSeconds  = CMTimeGetSeconds(self.player.currentItem!.asset.duration)

        t = CMTimeMakeWithSeconds(Float64(videoLengthInSeconds) *  Float64(0.5),  60000)
  do {

            let img : CGImageRef =  try assetImgGenerate.copyCGImageAtTime(t, actualTime: nil)
            let frameImg    : UIImage = UIImage(CGImage: img)
            return frameImg

        } catch let error as NSError {
            print("fucking nil")
            print(error)
        } catch {
            debugPrint("Generic error")
        }

iPad上的UIModalPresentationFormSheet。键盘出现时如何调整UITextView高度

2 个答案: