Xamarin - How to layer View on top of another, like Keyboard

Question

I have a custom UI I want to show like the keyboard when a user clicks a part of the screen. I've seen examples however they reference methods off of UIView which don't seem to exist (maybe it's because I have the Starter license?) for example UIView.beginAnimations isn't there.

Does anyone have a Xamarin (i.e. MonoTouch) example?

I want my UI piece to show, and to scroll the existing view so that the field is properly visible.

Answer 1

UITextView and UITextField have inputView property, which allows you to achieve exactly what you need. Setup the view, set it as their input view, and once the user makes a text view or a text field first responder, your view will appear. iOS7 has UIInputView class, which you can subclass, to achieve a similar background view as the keyboard.

Answer 2

Why don't you create your view and place it outside the visible view. When you want to show it, you just move it into the visible area. That way you can also add the animation.

NSLayoutConstraint *yourHiddenViewYConstraint;

- (void)viewDidLoad 
{
    [self.view addSubView:yourHiddenView];
    [yourHiddenView setHidden:YES];
    UIView *selfView = self.view
    yourHiddenView.translatesAutoresizingMaskIntoConstraints = NO;
    // add your needed constraints, other than the one below
    yourHiddenViewYConstraint = [NSLayoutConstraint constraintWithItem:yourHiddenView
                                                     attribute:NSLayoutAttributeTop
                                                     relatedBy:NSLayoutRelationEqual
                                                        toItem:selfView
                                                     attribute:NSLayoutAttributeTop
                                                    multiplier:1.0
                                                      constant:0];
    [selfView addConstraint:yourHiddenViewYConstraint];
    yourHiddenViewYConstraint.constant += self.view.frame.size.height;
}

To show it when needed:

- (void)showView
{
    [yourHiddenView setHidden:NO];
    dispatch_async(dispatch_get_main_queue(), ^(void) {
        [self changeConstraint:yourHiddenViewYConstraint withConstant:-self.view.frame.size.height];
    });
}

- (void)changeConstraint:(NSLayoutConstraint *)constraint withConstant:(CGFloat)constant
{
    constraint.constant += constant;

    void (^anim)(void) = ^{
        [self.view layoutIfNeeded];
    };

    [UIView animateWithDuration:0.5 animations:anim completion:nil];
}