addTextChangedListener in Android example

Create login application where you will have to validate EmailID(UserName). Till the user name and password is not validated , login button should remain disabled.

File Name : E3Activity.java

 package bsr.exa;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class E3Activity extends Activity {
 
/** @author Bipin S Rupadiya , www.BipinRupadiya.blogspot.in
     *
     *  3) Create login application where you will have to validate EmailID(UserName).
     *     Till the user name and password is not validated , login button should remain disabled.
     **/


String uname="rupadiyabipin@gmail.com";
String pwd="bipin";

boolean usrStatus=false;
boolean pwdStatus=false;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //create an intent
        final Intent intent=new Intent(this,Screen2.class);
        final Button cmdLogin = (Button) findViewById(R.id.cmdLogin);
        final EditText txtUsr = (EditText)findViewById(R.id.txtUsr);
        final EditText txtPwd = (EditText)findViewById(R.id.txtPwd);

     
        cmdLogin.setEnabled(false);
        cmdLogin.setOnClickListener(new Button.OnClickListener()
        {
        @Override
        public void onClick(View v)
        {
         
        intent.putExtra("uname1", txtUsr.getText().toString());
        intent.addFlags(intent.FLAG_ACTIVITY_CLEAR_TASK);
        intent.addFlags(intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
        //Toast.makeText(E3Activity.this, "welcome  ".txtUser.getText().toString().concat(" you are authenticated user!  "), Toast.LENGTH_LONG).show();
             
        }      
        });
        //------------------------------------------------
        //clear event
       final Button btnClear = (Button)findViewById(R.id.cmdClear);
       btnClear.setOnClickListener(new Button.OnClickListener()
        {
        @Override
        public void onClick(View v)
        {
        EditText fldu=(EditText)findViewById(R.id.txtUsr);
        EditText fldp=(EditText)findViewById(R.id.txtPwd);
        fldu.setText("");
        fldp.setText("");        
        }      
        });
     
        //------------------------------------------------

        txtUsr.addTextChangedListener(new TextWatcher()
        {

@Override
public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub
if(uname.equals(txtUsr.getText().toString()))
{
usrStatus=true;
}
else
{
usrStatus=false;
}
}

@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) {
// TODO Auto-generated method stub

}

@Override
public void afterTextChanged(Editable arg0) {
// TODO Auto-generated method stub
if(usrStatus && pwdStatus)
{
cmdLogin.setEnabled(true);
}
else
{
cmdLogin.setEnabled(false);
}

}
});
     
        txtPwd.addTextChangedListener(new TextWatcher() {

@Override
public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub

if(pwd.equals(txtPwd.getText().toString()))
{
pwdStatus=true;
}
else
{
pwdStatus=false;
}
}

@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub

}

@Override
public void afterTextChanged(Editable arg0) {
// TODO Auto-generated method stub

if(usrStatus && pwdStatus)
{
cmdLogin.setEnabled(true);
}
else
{
cmdLogin.setEnabled(false);
}
}
});
    }
 

}

File Name : Screen2.java

package bsr.exa;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
/** @author Bipin S Rupadiya , www.gtu-android.blogspot.com
 *
 *
 *
 **/
public class Screen2 extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
        super.onCreate(savedInstanceState);
     
        Intent intent=getIntent();
        String uname=intent.getStringExtra("uname1");    
        TextView tv=new TextView(this);
        Button btnBack = new Button(this);
     
        btnBack.setText("<<Back");
        tv.setText("Welcome "+uname+" !");

        tv.setTextColor(Color.rgb(255, 255, 255));
         
        tv.setTextSize(25);
     
        LinearLayout ll = new LinearLayout(this);
     
        ll.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
        ll.setOrientation(LinearLayout.VERTICAL);
        ll.addView(tv);
        ll.addView(btnBack);
        setContentView(ll);
     
        //------------------------------------------------
        //back event
        btnBack.setOnClickListener(new Button.OnClickListener()
        {
        @Override
        public void onClick(View v)
        {
        setContentView(R.layout.main);
        }      
        });
     
        //------------------------------------------------
}
}

AndroidManifest.xml

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

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

      package="bsr.exa"

      android:versionCode="1"

      android:versionName="1.0">

    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">

        <activity android:name=".E3Activity"

                  android:label="@string/app_name">

            <intent-filter>

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

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

            </intent-filter>

        </activity>

        <activity android:name="Screen2"></activity>

    </application>

</manifest>