iOS Tutorial Animate textfield/panel with the iOS keyboard

This post presents an implementation of animations that animate alongside the iOS keyboard animation. Following the method in this post will allow your views to animate smoothly when the iOS keyboard shows and hides.

A big thanks to @Erel who provided code to read the UIKeyboardAnimationDurationUserInfoKey when the keyboard opens or closes:

Get UIKeyboardAnimationDurationUserInfoKey and get UIKeyboardAnimationCurveUserInfoKey

I would like to synchronize the opening of my bottom sheet with a textfield on it, with the opening of the keyboard to create a smoother user experience. I come across tutorials online that read and work with the following 2 objects...

www.b4x.com

I have changed the code from the original post so that you can also read the UIKeyboardAnimationCurveUserInfoKey.
Add this objc code to the end of one of the modules:

#if OBJC
@end
@interface B4IViewController (Keyboard2)
@end
@implementation B4IViewController (Keyboard2)
- (void) addWillHide {
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardWillHideNotification object:nil];
}
- (void)keyboardWillShow:(NSNotification *)notification {
    CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
    [self storeAnimationInfo:notification];
    [B4IObjectWrapper raiseEvent:self :@"_keyboardstatechanged:" :@[@(keyboardSize.height)]];
}
- (void)storeAnimationInfo:(NSNotification*)notification {
    NSDictionary *userInfo = [notification userInfo];
    double duration = ((NSNumber*)[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey]).doubleValue;
    NSInteger curve = ((NSNumber*)[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey]).integerValue;
    
    NSMutableDictionary *map = [B4IObjectWrapper getMap:self];
    map[@"animation_duration"] = @(duration);
    map[@"animation_curve"] = @(curve);
}

- (void)keyboardDidHide:(NSNotification *)notification {
    [self storeAnimationInfo:notification];
    [B4IObjectWrapper raiseEvent:self :@"_keyboardstatechanged:" :@[@(0)]];
}
#end if

This code also adds the "will hide" event (https://www.b4x.com/android/forum/threads/keyboard-will-hide-notification.126640/#content). Note that the KeyboardStateChanged event will be raised twice when the keyboard closes.

This is the code for animating our text field or panel that can be placed directly under the other objc code:

#if OBJC
@end
@interface B4IViewController (KeyboardAnimator)
@end
@implementation B4IViewController (KeyboardAnimator)

- (void)animateView:(UIView *)view
       toYPosition:(CGFloat)y
          duration:(double)duration
             curve:(NSInteger)curve {
    
    UIViewAnimationCurve animCurve = (UIViewAnimationCurve)curve;

    UIViewPropertyAnimator *animator = [[UIViewPropertyAnimator alloc]
        initWithDuration:duration
        curve:animCurve
        animations:^{
            CGRect frame = view.frame;
            frame.origin.y = y;
            view.frame = frame;
            [self.view layoutIfNeeded];
    }];
    
    [animator startAnimation];
}

#end if

In B4XPage_Created call this:

#if B4i
    Dim no As NativeObject = B4XPages.GetNativeParent(Me) 'or Page1 in non-B4XPages project.
    no.RunMethod("addWillHide", Null)
#End If

Read out everything and animate the text field:

Private Sub B4XPage_KeyboardStateChanged (Height As Float)
    m_KeyboardHeight = Height
    Dim ow As NativeObject
    Dim duration As Int = ow.Initialize("B4IObjectWrapper").RunMethod("getMap:", Array(B4XPages.GetNativeParent(Me))) _
        .RunMethod("objectForKey:", Array("animation_duration")).AsNumber * 1000
    Log("duration in ms: " &  duration)
    Log("keyboard state changed: " & Height)
        
    Dim curveIndex As Int = ow.Initialize("B4IObjectWrapper").RunMethod("getMap:", Array(B4XPages.GetNativeParent(Me))) _
    .RunMethod("objectForKey:", Array("animation_curve")).AsNumber
    Log("curve: " & curveIndex)
        
    Dim Page As NativeObject = B4XPages.GetNativeParent(Me)
    If Height > 0 Then 'Keyboard is open
        xpnl_AddNewGroup.Top = Root.Height - xpnl_AddNewGroup.Height
        Page.RunMethod("animateView:toYPosition:duration:curve:", Array(xpnl_AddNewGroup, Root.Top + Root.Height - Height - xpnl_AddNewGroup.Height, duration, curveIndex))
    Else 'Keyboard is closed
        Page.RunMethod("animateView:toYPosition:duration:curve:", Array(xpnl_AddNewGroup,Root.Height - xpnl_AddNewGroup.Height - B4XPages.GetNativeParent(Me).SafeAreaInsets.Bottom, duration, curveIndex))
    End If
        
End Sub

Example project is attached.