How can you make a custom keyboard in Android?

Question

I want to make a custom keyboard. I don't know how to do it using XML and Java. The following picture is a model of the keyboard I want to make. It only needs numbers.

Answer 1

First of all you will need a keyboard.xml file which will be placed in the res/xml folder (if the folder does not exist, created it).

<?xml version="1.0" encoding="utf-8"?> 
<Keyboard xmlns:android="http://schemas.android.com/apk/res/android"
    android:keyWidth="15%p"
    android:keyHeight="15%p" >

    <Row>
        <Key android:codes="1"    android:keyLabel="1" android:horizontalGap="4%p"/>
        <Key android:codes="2"    android:keyLabel="2" android:horizontalGap="4%p"/>
        <Key android:codes="3"    android:keyLabel="3" android:horizontalGap="4%p" />
        <Key android:codes="4"    android:keyLabel="4" android:horizontalGap="4%p" />
        <Key android:codes="5"    android:keyLabel="5" android:horizontalGap="4%p" />
    </Row>
    <Row>
        <Key android:codes="6"    android:keyLabel="6" android:horizontalGap="4%p"/>
        <Key android:codes="7"    android:keyLabel="7" android:horizontalGap="4%p"/>
        <Key android:codes="8"    android:keyLabel="8" android:horizontalGap="4%p" />
        <Key android:codes="9"    android:keyLabel="9" android:horizontalGap="4%p" />
        <Key android:codes="0"    android:keyLabel="0" android:horizontalGap="4%p" />
    </Row>

    <Row>
        <Key android:codes="-1"    android:keyIcon="@drawable/backspace" android:keyWidth="34%p" android:horizontalGap="4%p"/>
        <Key android:codes="100"    android:keyLabel="Enter" android:keyWidth="53%p" android:horizontalGap="4%p"/>
    </Row>
 </Keyboard>

**Note that you will have to create the backspace drawable and place it in the res/drawable-ldpi folder with a very small size (like 18x18 pixels)

Then in the xml file that you want it to be used (where your TextView is in) you should add the following code:

<RelativeLayout
 ...
>

        .....


        <android.inputmethodservice.KeyboardView
             android:id="@+id/keyboardview"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_alignParentBottom="true"
             android:layout_centerHorizontal="true"
             android:focusable="true"
             android:focusableInTouchMode="true"
             android:visibility="gone" 
         />
         
        ......


</RelativeLayout>

**Note that the xml file that you will place the android.inputmethodservice.KeyboardView in, has to be RelativeLayout in order to be able to set the alignParentBottom="true" (Usually the keyboards are presented in the bottom of the screen)

Then you need to add the following code in the onCreate function of the Activity that handles the TextView you want to attach the keyboard to

    // Create the Keyboard
    mKeyboard= new Keyboard(this,R.xml.keyboard);

    // Lookup the KeyboardView
    mKeyboardView= (KeyboardView)findViewById(R.id.keyboardview);
    // Attach the keyboard to the view
    mKeyboardView.setKeyboard( mKeyboard );
    
    // Do not show the preview balloons
    //mKeyboardView.setPreviewEnabled(false);
    
    // Install the key handler
    mKeyboardView.setOnKeyboardActionListener(mOnKeyboardActionListener);

**Note that mKeyboard and mKeyboardView are private class variables that you have to create.

Then you need the following function for opening the keyboard ( you must associate it with the TextView through the onClick xml property)

    public void openKeyboard(View v)
    {
       mKeyboardView.setVisibility(View.VISIBLE);
       mKeyboardView.setEnabled(true);
       if( v!=null)((InputMethodManager)getSystemService(Activity.INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(v.getWindowToken(), 0);
    }

And finally you need the OnKeyboardActionListener that will handle your events

private OnKeyboardActionListener mOnKeyboardActionListener = new OnKeyboardActionListener() {
    @Override public void onKey(int primaryCode, int[] keyCodes) 
    {
         //Here check the primaryCode to see which key is pressed 
         //based on the android:codes property
         if(primaryCode==1)
         {
            Log.i("Key","You just pressed 1 button");
         }
    }

    @Override public void onPress(int arg0) {
    }

    @Override public void onRelease(int primaryCode) {
    }

    @Override public void onText(CharSequence text) {
    }

    @Override public void swipeDown() {
    }

    @Override public void swipeLeft() {
    }

    @Override public void swipeRight() {
    }

    @Override public void swipeUp() {
    }
};

Hope that helps!!!

Most of the code found here

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EDIT:

Since KeyboardView is depreciated since API level 29, you can find its code in this website and create a class in your code before implementing the keyboard as described above.