Free Online Tutorials

To learn how to validate a phone number, we create a simple example.

Step 1: create new android project
Step 2: create the layout: 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.tutorialspots.phonevalidate.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TUTORIALSPOTS.COM"
        android:textColor="#FF0000"
        android:textSize="30dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/textView" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Enter your phone number:"
        android:id="@+id/textView2"
        android:layout_below="@+id/textView"
        android:layout_centerHorizontal="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="phone"
        android:ems="15"
        android:id="@+id/editText"
        android:layout_below="@+id/textView2"
        android:layout_centerHorizontal="true" >
        <requestFocus />
    </EditText>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Validate"
        android:id="@+id/button"
        android:onClick="validatePhone"
        android:layout_below="@+id/editText"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

Step 3: file MainActivity.java

package com.tutorialspots.phonevalidate;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MainActivity extends AppCompatActivity {
    EditText editText;

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

        editText = (EditText) findViewById(R.id.editText);
    }

    public void validatePhone(View view){
        String phone = editText.getText().toString();
        if(isValidPhone(phone)){
            Toast.makeText(view.getContext(), "Phone number is valid", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(view.getContext(), "Phone number is invalid", Toast.LENGTH_LONG).show();
        }
    }

    public static boolean isValidPhone(String phone)
    {
        String expression = "^([0-9\\+]|\\(\\d{1,3}\\))[0-9\\-\\. ]{3,15}$";
        CharSequence inputString = phone;
        Pattern pattern = Pattern.compile(expression);
        Matcher matcher = pattern.matcher(inputString);
        if (matcher.matches())
        {
            return true;
        }
        else{
            return false;
        }
    }
}

Step 4: run for test

Sample phone number for test:

(425) 555-1212
+14255551212