How to make your own custom keyboard (in-app keyboard) for your Android App?

In this video it shows the steps to create your own custom keyboard for your Android App.

I hope you like this video. For any questions, suggestions or appreciation please contact us at: https://programmerworld.co/contact/ or email at: programmerworld1990@gmail.com

Complete source code and other details:

package com.programmerworld.mycustomkeyboardapp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.text.InputType;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        EditText editText = findViewById(R.id.editText);
        editText.setShowSoftInputOnFocus(false);
        editText.setRawInputType(InputType.TYPE_CLASS_TEXT);

        InputConnection inputConnection = editText.onCreateInputConnection(new EditorInfo());

        KeyboardCustomJava keyboardCustomJava = findViewById(R.id.keyboardCustom);
        keyboardCustomJava.setInputConnection(inputConnection);
    }
}

package com.programmerworld.mycustomkeyboardapp;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.inputmethod.InputConnection;
import android.widget.Button;
import android.widget.LinearLayout;

import androidx.annotation.Nullable;

public class KeyboardCustomJava extends LinearLayout implements View.OnClickListener {

    private InputConnection inputConnection;

    private Button button1;
    private Button button2;
    private Button button3;
    private Button button4;
    private Button button5;
    private Button button6;
    private Button button7;
    private Button button8;
    private Button button9;
    private Button buttonA;
    private Button buttonB;
    private Button buttonC;


    public KeyboardCustomJava(Context context) {
        super(context);
        initialization(context);
    }

    public KeyboardCustomJava(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initialization(context);
    }

    public KeyboardCustomJava(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initialization(context);
    }

    public KeyboardCustomJava(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        initialization(context);
    }

    private void initialization(Context context){
        LayoutInflater.from(context).inflate(R.layout.keybaord_custom, this, true);
        button1 = findViewById(R.id.b1);
        button2 = findViewById(R.id.b2);
        button3 = findViewById(R.id.b3);
        button4 = findViewById(R.id.b4);
        button5 = findViewById(R.id.b5);
        button6 = findViewById(R.id.b6);
        button7 = findViewById(R.id.b7);
        button8 = findViewById(R.id.b8);
        button9 = findViewById(R.id.b9);
        buttonA = findViewById(R.id.bA);
        buttonB = findViewById(R.id.bB);
        buttonC = findViewById(R.id.bC);

        button1.setOnClickListener(this);
        button2.setOnClickListener(this);
        button3.setOnClickListener(this);
        button4.setOnClickListener(this);
        button5.setOnClickListener(this);
        button6.setOnClickListener(this);
        button7.setOnClickListener(this);
        button8.setOnClickListener(this);
        button9.setOnClickListener(this);
        buttonA.setOnClickListener(this);
        buttonB.setOnClickListener(this);
        buttonC.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if (inputConnection == null){
            return;
        }
        String stringValue = ((Button) view).getText().toString();
        inputConnection.commitText(stringValue, 1);
    }

    public void setInputConnection(InputConnection inputConnectionLocal){
        this.inputConnection = inputConnectionLocal;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="347dp"
        android:layout_height="101dp"
        android:layout_marginStart="31dp"
        android:layout_marginTop="70dp"
        android:ems="10"
        android:hint="Test the keyboard here ..."
        android:inputType="text" />

    <com.programmerworld.mycustomkeyboardapp.KeyboardCustomJava
        android:id="@+id/keyboardCustom"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true" />
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <Button
                android:id="@+id/b1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="1" />

            <Button
                android:id="@+id/b2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="2" />

            <Button
                android:id="@+id/b3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="3" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <Button
                android:id="@+id/b4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="4" />

            <Button
                android:id="@+id/b5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="5" />

            <Button
                android:id="@+id/b6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="6" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <Button
                android:id="@+id/b7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="7" />

            <Button
                android:id="@+id/b8"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="8" />

            <Button
                android:id="@+id/b9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="9" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <Button
                android:id="@+id/bA"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="A" />

            <Button
                android:id="@+id/bB"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="B" />

            <Button
                android:id="@+id/bC"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="C" />
        </LinearLayout>
    </LinearLayout>

</merge>

Screenshots: