How to build a custom keyboard in Xamarin?

In this case, ordinary keyboards in operating systems cannot meet the needs, and the need to design and build custom keyboards increases. In this case, if the designed keyboard is separate from the  application  and the application is not launched within the application, it cannot meet the need properly. So the only solution for this set is to design a custom keyboard that can be launched inside the application to meet all the needs. This article describes how to design and build a custom keyboard. If you want to design a custom keyboard for  built-in applications, it is recommended that you follow this article.

The best way to design and build a custom keyboard to run within the app is to go native. By following this path, you can easily design a keyboard launched inside the application. Other users do not need to download that keyboard separately to use this keyboard in designing a custom keyboard using Xamarin. Forms, we need the Custom Renderer option. This option is used to control entries.

The  Xamarin.Forms  version must be high to design and build a custom keyboard with the OnFocusChangeRequest method. Any version of Xamarin.Forms that have the OnFocusChangeRequest method are suitable for custom keyboard design. We create a custom control that has a bindable attribute using this method. This feature is used for connection, and this feature with features such as EnterCommand and ICommand causes the active connection to be pressed on the keyboard button. Therefore, to build the keyboard, we have to use the version of Xamarin. Forms, which has the OnFocusChangeRequest method, because using this method, we will create a connectivity feature that turns the pressing of a key on the keyboard into action.

All the Android packages required to design and build a custom keyboard are as follows:

- Xamarin.Android. Support.Compat
- Xamarin.Android. Support.Core.UI
- Xamarin.Android. Support.Core. Utils
- Xamarin.Android. Support.CustomTab
- Xamarin.Android. Support.Design
- Xamarin.Android. Support.Transition
- Xamarin.Android. Support.v4
- Xamarin.Android. Support.v7. AppCompact
- Xamarin.Android. Support.v7. CardView
- Xamarin.Android. Support.v7. MediaRouter

To design a custom keyboard for Android using  Xamarin.Forms, all of the above  Android  packages must be present.

1- We need to write code that supports the bindable attribute and causes the action to be connected to the KeyKey.

2- For our custom-designed keyboard to appear in  applications, we must prevent the native keyboard of our operating system from appearing. To do this, we need to use the SoftInputMode.StateAlwaysHidden property.

3- The next step after preventing the appearance of the native keyboard of the operating system is to build and  design a custom application  4- To do this, go to the Resource/layout folder.
5- we will create an  Android  file in this folder.
6- We choose a name for this layout, the chosen name in this tutorial is CustomKeyboard.
7- The type of output created is better to be InputMethodService.Keyboard.

8- Then, we set the alignParentBottom attribute to true so that the keyboard appears at the bottom of the screen.

9- For the layout to react by pressing a key on the keyboard, the keyPreviewLayout attribute must be set to null and react when a key is pressed from the created layout keyboard.

10- Go to the Drawable folder and create a drawable.

11- In this tutorial, we will name the created drawable keyboard_background.

12- Create the drawable created inside the Drawable folder as an xml. File. Reason to create drawable

The key background attribute points to and needs to be built.

13- To build an xml. File, we consider two modes. Normal mode and pressed mode.

14- It should be noted that the normal mode is for when the KeyKey is not pressed, and the pressed mode is when the KeyKey is pressed.

15- To do this, I create two xml. Files inside the Drawable file. One for normal mode and the other for pressed mode.

16- The codes that will be included in the normal.xml.file for normal mode are as follows:

I was using these codes in the normal.xml.file, I specify the keyboard behavior for when no key is pressed.

17- The codes that will be included in the pressed.xml.file for the pressed mode are as follows:

I am using this code in the pressed.xml.file, I specify the keyboard behavior for when the KeyKey is pressed.

18- After determining the behavior for when the KeyKey is pressed or not, we create an xml-file for ids inside the values ​​folder, which will be used in the next steps.

19- In the next step, to specify and define specific keyboard keys, go to the Resources folder and create an xml-file in it.

20- In the xml-file created in the Resources folder, create an xml-file again.

21- This section will specify the horizontal, vertical, horizontal, and vertical gap dimensions.

22- I use separating lines to separate the rows of keyboards from each other. To do this, we create an xml-file inside the Drawable folder and name it kb_separator_line.xml to determine the properties of the separator lines by assigning and coding inside this file.

Note:

Each KeyKey has two attributes, codes and key labels.

- Each KeyKey has a unique number that the codes attribute tells the operating system in the system language which KeyKey is pressed.
- the key label is a string to be displayed after the KeyKey is pressed. Even if you do not want something to appear or be displayed by pressing a key, you must set it. The value of this characteristic is of great importance. If you do not want something displayed when a key is pressed, it must be set to " = key label.

23- We use the  keyEdgeFlags attribute  to style with the keyboard keys and determine the state of the initial and final keys. These keys are set to leave or right and specify the state of each KeyKey on the keyboard.

24- To style with the keyboard keys, make an xml. The file called special_keyboard.xml inside the Drawable folder and put the following code inside it.

Note:

Each row of keyboard keys is placed inside the tags.

25- For our designed keyboard to appear in the application, we need to create an animation to make the keyboard appear. To do this, create a file in the Resources folder and name it, for example, anim.

26- In the anime folder that we created, we built an xml. File to put the codes related to the keyboard's appearance as animation inside it. Name the xml.file slide_in_bottom.

27- For the written code to be rendered, we create a new Renderers file inside the Android project.

28- Inside the created Renderers folder, we define our renderer called EntryWithCustomKeyboardRenderer, and it implements the IOnKeyboardActionListener interface. This renderer is an extension of EntryRenderer.

29- Then, to avoid null exceptions, we define a private class called NullListener. This class, defined to avoid null exceptions, will be extended from Java. Lang. Object.

30- To continue  designing the keyboard, go to the Xamarin.Forms project  and put the following code in the MainPage.xaml file.

31- Put the following code in the MainPage.cs file.

By following the steps of this tutorial, you can  create a custom keyboard  for the  Android  operating system and platform.