XamarinAndroidEntry

Custom Entry for Xamarin Forms with full control over the virtual keyboard

Update per 2020/12/06

It's now possible to set the vertical Alignment as well (use YAlign). The Sample app has been extended to show this feature.

Update per 2020/04/20

The previous version did not work on devices running Oreo (8.0/API 26) and above. It was necessary to set the property ShowSoftInputOnFocus on the native edittext to false. With that modification the solution works as expected on newer systems (up to 10.0 tested in simulator).

Why this sample?

Our app (part of our ERP system) runs on several different devices with Windows CE, iOS and Android. Most of the data entered into the system is scanned but some data (mostly quantities) has to be entered manually. Occasionally one has to enter some text as well.

That implies that in some fields you would like to get the virtual keyboard immediately while you want to get it in others only if needed.

In addition there are some devices that have a hardware keyboard. You don't want to get the keyboard there altogether. Of course you would like to have full control over this feature.

I have searched the internet quite a lot and found several samples but all of them lacked some functionality here and there.

So I decided to combine them into one sample control and an create a small app to showcase the control.

Features of the app:

• 3 Fields and a toolbar button to toggle the virtual keyboard on and off
• The first field does not show the keyboard on focus
• The second field has IsPassword=true set (keyboard off)
• The third field shows the virtual keyboard immediately on focus
• All fields have full support for copy (not on password, of course) and paste

Features of the control:

1. Full control over the appearance and disappearance of the virtual keyboard
2. A property to control if the keyboard should appear on focus automatically
3. An additional object that gives an event when the keyboardheight changes (= when the keyboard appears and disappears). It allows you to modify your layout accordingly, if necessary.
   Please note that you don't need this if your layout is done like in the sample app. In that case Android does quite a good job to keep the important parts of your layout visible.

A few notes regarding ExtendedEntry:

• The key point of this story is the following:
  You MUST override the Focus() method of Entry and you MUST NOT call the base implementation in your code.
  If you call base.Focus() the virtual keyvoard will appear occasionally regardless what you do in your code. In my experience you can reduce this but you will never get it fully under control.
• As an additional benefit your code is much smaller and easier to understand and maintain if you do not call base.Focus().
  E.g. you do not have to meddle with the inputtype-property to keep track of the keyboard type that should be shown and using the IsPassword-Property works without any additional code (see sample)

Some key lines in the code:

ExtendedEntryRenderer.OnElementChanged:

• Setting SetTextIsSelectable(true) has two purposes:

  1. It allows to copy and paste text without additional code
  2. The cursor will appear and blink even if the virtual keyboard is not visible
     This is very helpful if you have a hardware keyboard or you would like to know where the next scan will enter text

• Setting SetSelectAllOnFocus(true) automatically selects the context of Entry() when it gets the focus
  (regardless of the visibility of the keyboard)

App.OnStart:

• App.Current.On().UseWindowSoftInputModeAdjust(WindowSoftInputModeAdjust.Resize)
  This is needed for the automatic resizing of your layout when the virtual keyboard appears and disappears. Without that the whole screen will scroll not the scrollbar inside your view (see sample)

Additions to Entry:

• Property ShowVirtualKeyboardOnFocusProperty (bindable)
  When true shows the keyboard automatically when the cotrol gets the focus
• Method ShowKeyboard()
  Show the virtual keyboard
• Method HideKeyboard()
  Hide the virtual keyboard

Object SoftwareKeyboardService:

• Event KeyboardHeightChanged(SoftwareKeyboardEventArgs e)
  Fired when the area on the screen occupied by the keyboard changes.
  SoftwareKeyboardEventArgs contains a field with the current height of the keyboard to allow you to justify your layout accordingly
• Property bool IsKeyboardVisible
  Allows you to check if the virtual keyboard is currently visible