Apply validations to Contact Form in Android application

Hi friends ,In this article i would like to explain how to apply validations in android applications..Here i am going to explain only Required Field Validations later i will explain Regular expressions and so on..so lets start

First ,Create a New android project and open the main.xml file





Next,Design the form ,I have already explained how to create a contact form in android
http://www.developerscode.com/2012/02/create-socail-network-contact-form-in.html


after the designing process is completed .Open the ValidationsActivity.java class and write the following code

public class ValidationsActivity extends Activity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);        
        final EditText name=(EditText) findViewById(R.id.name);
        final EditText email=(EditText) findViewById(R.id.email);
        final EditText mobile=(EditText) findViewById(R.id.mobile);
        final EditText message=(EditText) findViewById(R.id.message);
        
        Button submit = (Button) findViewById(R.id.submit);    
        submit.setOnClickListener(new OnClickListener() {    
   public void onClick(View v)
   {
     
    if(name.getText().toString().length()==0)
          {         
           name.setError( "Please Enter Name" );
          }
    else if(email.getText().toString().length()==0)
          {         
           email.setError( "Please Enter Email" );
          }    
    else if(mobile.getText().toString().length()<10)
          {         
           mobile.setError( "Please Enter Valid Mobile No" );
          }
    else if(message.getText().toString().length()==0)
          {         
           message.setError( "Please Enter Message" );
          }
    else
    {
     Intent submitform=new 

Intent(ValidationsActivity.this,Home.class);
     startActivity(submitform);
    } 
   }   
  });
    }
}

Code Explanation : 

 final EditText name=(EditText) findViewById(R.id.name); means

 assiging a name to the control 

name.setError( "Please Enter Name" ); means

 it displays a custom message what ever want 

Intent submitform=new Intent(ValidationsActivity.this,Home.class);

means 

Once the form is successfully submitted..it will redirects to Home screen

 Thats it...Happy Coding...:)