Create Information Dialog in Android

Create new project in Android Studio with steps as below:

Open res\values\strings.xml file and add new string as below:

<resources>
    <string name="app_name">Learn Android with Real Apps</string>
    <string name="show_dialog">Show Dialog</string>
    <string name="information">Information</string>
    <string name="done">Done</string>
    <string name="ok">OK</string>
</resources>

Open res\layout\activity_main.xml file and create layout as below:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/buttonShowDialog"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/show_dialog" />

</LinearLayout>

Add code to MainActivity.java in android.demo.learnandroidwithrealapps package as below:

package android.demo.learnandroidwithrealapps;

import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    private Button buttonShowDialog;

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

    private void initView() {
        buttonShowDialog = findViewById(R.id.buttonShowDialog);
        buttonShowDialog.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                buttonShowDialog_onClick(view);
            }
        });
    }

    private void buttonShowDialog_onClick(View view) {
        AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());
        builder.setTitle(R.string.information);
        builder.setMessage(R.string.done);
        builder.setCancelable(false);
        builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
            }
        });
        builder.show();
    }

}