How to obtain the phone number of the android phone programmatically?

This example demonstrates how do I obtain the phone number of the android phone programmatically.

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"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/textView"
      android:layout_centerInParent="true"
      android:textSize="24sp"
      android:textStyle="bold"/>
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.java

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
   TextView textView;
   private static final int REQUEST_CODE = 101;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      textView = findViewById(R.id.textView);
      TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
      if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED &&
         ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_NUMBERS) != PackageManager.PERMISSION_GRANTED &&
         ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_PHONE_STATE}, REQUEST_CODE);
      }
      textView.setText(telephonyManager.getLine1Number());
   }
   @Override
   public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults){
      switch (requestCode) {
         case REQUEST_CODE: {
            if(grantResults[0] == PackageManager.PERMISSION_GRANTED){
               Toast.makeText(this, "Permission Granted",Toast.LENGTH_SHORT).show();
            } else {
               Toast.makeText(this, "Permission Denied",Toast.LENGTH_SHORT).show();
            }
         }
      }
   }
}

Step 4 - Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.sample">
   <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

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 –

Click here to download the project code.