How to make custom dialog in android?

This example demonstrate about how to make custom dialog in android.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:id="@+id/parent"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity"
   android:gravity="center"
   android:orientation="vertical">
   <Button
      android:id="@+id/customDialog"
      android:text="Custom Dialog"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
</LinearLayout>
In the above code, we have taken button. When user click on button, it will show custom dialog.
Step 3 − Add the following code to src/MainActivity.java
package com.example.andy.myapplication;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MainActivity extends AppCompatActivity {
   @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      findViewById(R.id.customDialog).setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
            ViewGroup viewGroup = findViewById(android.R.id.content);
            View dialogView = LayoutInflater.from(v.getContext()).inflate(R.layout.customview, viewGroup, false);
            builder.setView(dialogView);
            AlertDialog alertDialog = builder.create();
            alertDialog.show();
         }
      });
   }
}
To show custom dialog we have inflated a view as custom view. so create customview.xml and add the following code -
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:orientation="vertical">
   <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"
      android:padding="16dp">
      <TextView
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:text="Success"
         android:textAlignment="center"
         android:textAppearance="@style/TextAppearance.AppCompat.Headline" />
      <TextView
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_marginTop="10dp"
         android:text="Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla eu erat tincidunt lacus fermentum rutrum."
         android:textAlignment="center"
         android:textAppearance="@style/TextAppearance.AppCompat.Medium" />
      <Button
         android:id="@+id/buttonOk"
         android:layout_width="200dp"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
         android:layout_marginTop="15dp"
         android:background="@color/colorPrimary"
         android:text="Ok"
         android:textColor="#FFF" />
   </LinearLayout>
</LinearLayout>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −
In the above result, it shown initial screen. Now click on button it will open custom dialog as shown below -
Click here to download the project code