关于 ios：iPad 上的 UIModalPresentationFormSheet。键盘出现时如何调整UITextView的高度

UIModalPresentationFormSheet on iPad. How to adjust UITextView height when keyboard appears

UITextView 是模态控制器视图的子视图。当键盘出现时，我需要降低 UITextView 的高度，以便 UITextView 的底部边框 y 坐标等于键盘的顶部 y 坐标。
我正在获取键盘高度

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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这个模态视图会跳起来。这种情况下如何计算键盘的上边框坐标？

你可以这样做：

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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];
}

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