问题
I've got a view controller listening for both UIKeyboardWillShowNotification and UIKeyboardWillHideNotification. The handlers for these notifications adjust various parts of the view, which is standard procedure.
The following code is used to convert the keyboard rect from screen coordinates:
CGRect keyboardBounds = [self.view convertRect:[keyboardBoundsValue CGRectValue] fromView:nil];
Again, standard procedure. Unfortunately, there is a critical situation where this conversion fails. Look at what happens when an iPhone is rotated from portrait to landscape while the keyboard is deployed:
1) iOS automatically fires UIKeyboardWillHideNotification; self.interfaceOrientation is reported as portrait; keyboardBounds.height is 216.0. This makes sense. Why? Because the notification handler is given the chance to "clean up" before the view switches to landscape mode.
2) iOS automatically fires UIKeyboardWillShowNotification; self.interfaceOrientation is reported as portrait; keyboardBounds.height is 480.0. This does NOT make sense. Why not? Because the notification handler is going to do its work thinking that the height of the keyboard is 480.0!
Did Apple drop the ball on this one, or am I doing something wrong?
Please note that listening instead for UIKeyboardDidShowNotification is not a valid solution, because it significantly degrades the user experience. Why? Because animating my changes to the view after the keyboard deployment animation occurs is... well, pretty terrible-looking.
Has anyone managed to get autorotation working perfectly while the keyboard is deployed? It seems like an explosion of chaos that Apple has completely overlooked. >:|
回答1:
Maybe a bit late, but I've just run into the same issue and have a nice solution for it that avoids any kind of work arounds (unless of course apple change things)
Basically, when the notification center calls your method for UIKeyboardWillShowNotification (or any of the other notifications), the frame that it gives you for UIKeyboardFrameBeginUserInfoKey is in context of the window, NOT your view. The problem with this, is that the windows coordinate system is always in portrait, regardless of the devices orientation, hence you're finding the width and height the wrong way round.
If you want to avoid your work around, simply convert the rectangle into the coordinate system of your view (which does change according to the orientation). To do this, do something like the following :
- (void) keyboardWillShow:(NSNotification *)aNotification
{
CGRect keyboardFrame = [[[aNotification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
CGRect convertedFrame = [self.view convertRect:keyboardFrame fromView:self.view.window];
......
/* Do whatever you want now with the new frame.
* The width and height will actually be correct now
*/
......
}
Hopefully this should be what you're after :)
回答2:
Recently I've wrote a blog post about this exact problem you've described and how to solve it with a short and elegant way. Here is the link to the post: Synchronizing rotation animation between the keyboard and the attached view
If you don't want to dive into the long explanation described in the blog post here is a short description with a code example:
The basic principle is to use the same method that everyone uses - observing keyboard notifications to animate the attached view up and down. But in addition to that, you have to cancel these animations when the keyboard notifications are fired as a consequence of interface orientation change.
Rotation example without animation cancellation custom on interface orientation change:
Rotation example with animation cancellation on interface orientation change:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter]
addObserver:self selector:@selector(adjustViewForKeyboardNotification:)
name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter]
addObserver:self selector:@selector(adjustViewForKeyboardNotification:)
name:UIKeyboardWillHideNotification object:nil];
}
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
[[NSNotificationCenter defaultCenter]
removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter]
removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
[super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
self.animatingRotation = YES;
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
[super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
self.animatingRotation = NO;
}
- (void)adjustViewForKeyboardNotification:(NSNotification *)notification {
NSDictionary *notificationInfo = [notification userInfo];
// Get the end frame of the keyboard in screen coordinates.
CGRect finalKeyboardFrame = [[notificationInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
// Convert the finalKeyboardFrame to view coordinates to take into account any rotation
// factors applied to the window’s contents as a result of interface orientation changes.
finalKeyboardFrame = [self.view convertRect:finalKeyboardFrame fromView:self.view.window];
// Calculate new position of the commentBar
CGRect commentBarFrame = self.commentBar.frame;
commentBarFrame.origin.y = finalKeyboardFrame.origin.y - commentBarFrame.size.height;
// Update tableView height.
CGRect tableViewFrame = self.tableView.frame;
tableViewFrame.size.height = commentBarFrame.origin.y;
if (!self.animatingRotation) {
// Get the animation curve and duration
UIViewAnimationCurve animationCurve = (UIViewAnimationCurve) [[notificationInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
NSTimeInterval animationDuration = [[notificationInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
// Animate view size synchronously with the appearance of the keyboard.
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:animationDuration];
[UIView setAnimationCurve:animationCurve];
[UIView setAnimationBeginsFromCurrentState:YES];
self.commentBar.frame = commentBarFrame;
self.tableView.frame = tableViewFrame;
[UIView commitAnimations];
} else {
self.commentBar.frame = commentBarFrame;
self.tableView.frame = tableViewFrame;
}
}
This answer was also posted in similar question: UIView atop the Keyboard similar to iMessage App
回答3:
I met the same problem. iOS gaves me incorrect width/height of the keyboard. I used the following snipped in a keyboardDidShow handler:
CGSize keyboardSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
CGSize keyboardSize2 = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
LogDbg(@"keyboard size: frameBegin=%@; frameEnd=%@", NSStringFromCGSize(keyboardSize), NSStringFromCGSize(keyboardSize2));
and for portrait and landscape modes of iPad I got respectively:
2012-06-14 04:09:49.734 -[LoginViewController keyboardDidShow:] 132 [DBG]:keyboard size: frameBegin={768, 264}; frameEnd={768, 264}
2012-06-14 04:10:07.971 -[LoginViewController keyboardDidShow:] 132 [DBG]:keyboard size: frameBegin={352, 1024}; frameEnd={352, 1024}
Guessing that the width of the keyboard should be greater then the height (yep, i'm so naive) I made a workaround like following:
if (keyboardSize.width < keyboardSize.height)
{
// NOTE: fixing iOS bug: http://stackoverflow.com/questions/9746417/keyboard-willshow-and-willhide-vs-rotation
CGFloat height = keyboardSize.height;
keyboardSize.height = keyboardSize.width;
keyboardSize.width = height;
}
回答4:
Well, try looking at keyboard width. If it is the value that you are expecting, then I assume that the values are simply switched ;). 480 makes sense as a keyboard width for going into landscape, which is what gives me this hunch.
If that fails, just store the portrait and landscape rectangles separately. They are well documented ;)
回答5:
I know this a very very late reply. Now only I came on this situation and find the unanswered question. So I thought I'll share my solution. There will be some other better way, but the following way also we can solve this.
The KBKeyboardHandler that I used is from: UITextField: move view when keyboard appears
I just changed my delegate as following:
- (void)keyboardSizeChanged:(CGSize)delta
{
CGRect frame = self.view.frame;
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
switch (interfaceOrientation) {
case UIInterfaceOrientationPortrait:
frame.origin.y-=delta.height;
break;
case UIInterfaceOrientationPortraitUpsideDown:
frame.origin.y+=delta.height;
break;
case UIInterfaceOrientationLandscapeLeft:
frame.origin.x-=delta.height;
break;
case UIInterfaceOrientationLandscapeRight:
frame.origin.x+=delta.height;
break;
default:
break;
}
self.view.frame = frame;
}
And it was working fine.
回答6:
Here is my workaround:
CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
float keyboardHeight = self.interfaceOrientation == UIInterfaceOrientationPortrait ? keyboardSize.height : keyboardSize.width;
Hope this helps :)
回答7:
I use the following code to get the size of the keyboard which works fine for all rotations
NSDictionary *info = [aNotification userInfo];
if (UIInterfaceOrientationIsLandscape(self.interfaceOrientation))
kbHeight = [[NSNumber numberWithFloat:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.width] floatValue];
else
kbHeight = [[NSNumber numberWithFloat:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height] floatValue];
NSLog(@"keyboard height = %F",kbHeight);
I then test for the orientation using the status bar orientation (which works in the first launch case for the iPad) and shift the view in the relative direction needed to make space for the keyboard. This works perfectly, if the keyboard is visible then it relocates to the correct position on rotations.
UIDeviceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if (orientation == UIDeviceOrientationPortrait)
{
NSLog(@"Orientation: portrait");
self.originalCenter = self.view.center;
self.view.center = CGPointMake(self.originalCenter.x, self.originalCenter.y-kbHeight);
}
if (orientation == UIDeviceOrientationPortraitUpsideDown)
{
NSLog(@"Orientation: portrait upside down");
self.originalCenter = self.view.center;
self.view.center = CGPointMake(self.originalCenter.x, self.originalCenter.y+kbHeight);
}
if (orientation == UIDeviceOrientationLandscapeLeft)
{
NSLog(@"Orientation: landscape left");
self.originalCenter = self.view.center;
self.view.center = CGPointMake(self.originalCenter.x+kbHeight,self.originalCenter.y);
}
if (orientation == UIDeviceOrientationLandscapeRight)
{
NSLog(@"Orientation: landscape right");
self.originalCenter = self.view.center;
self.view.center = CGPointMake(self.originalCenter.x-kbHeight,self.originalCenter.y);
}
You can return the view to its original position when the keyboard disappears or via a textFileDidEndEditing function.
来源：https://stackoverflow.com/questions/9746417/keyboard-willshow-and-willhide-vs-rotation