ANDROID FORM VALIDATION EXAMPLE

Form Validation Example:

This is a Examle showing how to validat the data user entered

The form validation has done using the RegularExpressions 

1.Create New Android Projet

2.Add the following data in the main_activity.xml

res/layout/main_activity.xml

<?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" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Username" />

    <EditText

        android:id="@+id/editText1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:ems="10" >

        <requestFocus />

    </EditText>

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Password" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:ems="10"

        android:inputType="textPassword" />

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Email" />

    <EditText

        android:id="@+id/editText3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:ems="10"

        android:inputType="textEmailAddress" />

    <Button

        android:id="@+id/btnSubmit"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Submit" />

</LinearLayout>

3.Create The Activity Class For The xml File As Shown Below

package com.example.gurumurthy;

import java.util.regex.Pattern;

import android.os.Bundle;

import android.app.Activity;

import android.util.Log;

import android.view.Menu;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class MainActivity extends Activity {

private static final Pattern EMAIL_PATTERN = Pattern

.compile("[a-zA-Z0-9+._%-+]{1,100}" + "@"

+ "[a-zA-Z0-9][a-zA-Z0-9-]{0,10}" + "(" + "."

+ "[a-zA-Z0-9][a-zA-Z0-9-]{0,20}"+

             ")+");

private static final Pattern USERNAME_PATTERN = Pattern

.compile("[a-zA-Z0-9]{1,250}");

private static final Pattern PASSWORD_PATTERN = Pattern

.compile("[a-zA-Z0-9+_.]{4,16}");

EditText usname;

EditText pword;

EditText email1;

Button btSubmit;

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Log.v("HELLO","ONCREATE");

usname = (EditText) findViewById(R.id.editText1);

pword = (EditText) findViewById(R.id.editText2);

email1 = (EditText) findViewById(R.id.editText3);

btSubmit = (Button) findViewById(R.id.btnSubmit);

btSubmit.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

String username = usname.getText().toString();

String password = pword.getText().toString();

String email = email1.getText().toString();

if (username.equals("") || password.equals("")

|| email.equals("")) {

if (username.equals("")) {

Toast.makeText(MainActivity.this, "ENTER USERNAME",

Toast.LENGTH_LONG).show();

}

if (password.equals("")) {

Toast.makeText(MainActivity.this, "ENTER PASSWORD",

Toast.LENGTH_LONG).show();

}

if (email.equals("")) {

Toast.makeText(MainActivity.this, "ENTER EMAIL ID",

Toast.LENGTH_LONG).show();

}

} else {

if (!CheckUsername(username)) {

Toast.makeText(MainActivity.this, "ENTER VALID USERNAME",

Toast.LENGTH_LONG).show();

}

if (!CheckPassword(password)) {

Toast.makeText(MainActivity.this, "ENTER VALID PASSWORD",

Toast.LENGTH_LONG).show();

}

if (!CheckEmail(email)) {

Toast.makeText(MainActivity.this, "ENTER VALID EMAIL ID",

Toast.LENGTH_LONG).show();

}

}

}

private boolean CheckEmail(String email) {

return EMAIL_PATTERN.matcher(email).matches();

}

private boolean CheckPassword(String password) {

return PASSWORD_PATTERN.matcher(password).matches();

}

private boolean CheckUsername(String username) {

return USERNAME_PATTERN.matcher(username).matches();

}

});

}

}

4.After creating an Activity file Register the Activity File in the manifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.gurumurthy"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="17" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="com.example.gurumurthy.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

    </application>

</manifest>

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