UIView atop the Keyboard similar to iMessage App

Question

currently I\'m attempting to basically implement and exact copy of Apples iMessage App.

That means I need a UITextView that is docked at the bottom of the screen, an

Answer 1

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 by using keyboard notifications but without using the inputAccessoryView. And although this question is pretty old this topic is still relevant so 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;
    }
}