Exercise : 3
Create login application where you will have to validate EmailID(UserName). Till the username and password is not validated , login button should remain disabled.

Screen Shot:

XML :

main.xml :

JAVA :

ThirdActivity.java :

package kmn.Third;
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.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class ThirdActivity extends Activity implements OnClickListener,TextWatcher
{
    /**@author GTU MCA PPT, www.gtumcappt.com */
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        EditText txtemail = (EditText)findViewById(R.id.txtemail);
        EditText txtpassword = (EditText)findViewById(R.id.txtpassword);
        txtemail.addTextChangedListener(this);
        txtpassword.addTextChangedListener(this);
        Button btn = (Button)findViewById(R.id.btnlogin);
        btn.setOnClickListener(this);
    }
    public void onClick(View v)
    {
     EditText txte = (EditText)findViewById(R.id.txtemail);
        EditText txtp = (EditText)findViewById(R.id.txtpassword);
        
if(txte.getText().toString().equals("keval") && txtp.getText().toString().equals("nagaria"))
     {
      Intent i = new Intent(this,S2.class);
      i.putExtra("txte", txte.getText().toString());
      startActivity(i);
      
      //Toast.makeText(this, "Login...",Toast.LENGTH_LONG).show();
     }
     else
     {
      Toast.makeText(this, "Invalid",Toast.LENGTH_LONG).show();
     }
    }
    public void afterTextChanged(Editable s)
    {
     EditText txte = (EditText)findViewById(R.id.txtemail);
        EditText txtp = (EditText)findViewById(R.id.txtpassword);
        Button btn = (Button)findViewById(R.id.btnlogin);
        if(txte.getText().toString().equals("keval") &&     txtp.getText().toString().equals("nagaria"))
     {
      btn.setEnabled(true);
     }
     else
     {
      btn.setEnabled(false);
     }
    }
 public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
   int arg3) {
  // TODO Auto-generated method stub
  
 }
 public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
  // TODO Auto-generated method stub
  
 }
}

S2.java :

package kmn.Third;

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;

public class S2 extends Activity
{
    /**@author GTU MCA PPT, www.gtumcappt.com */
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Intent i= getIntent();  
        //Toast.makeText(this,"Welcome",Toast.LENGTH_LONG).show();
        String txte=i.getStringExtra("txte");       
        TextView tv=new TextView(this);
        Button btnBack = new Button(this);
        btnBack.setText("Back");
        tv.setText("Welcome "+txte+" !");
        tv.setTextColor(Color.rgb(255, 255, 100));            
        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);
        
        btnBack.setOnClickListener(new Button.OnClickListener()
        {
         public void onClick(View v)
         {
          //setContentView(R.layout.main);
          finish();
         }        
        });
    }
}

Exercise : 2

To understand Activity, Intent

a. Create sample application with login module.(Check username and password)

b. On successful login, go to next screen. And on failing login, alert user using Toast.

c. Also pass username to next screen

Screen Shot:

XML :

main.xml :

JAVA :

SecondActivity.java :

package kmn.Second;

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

public class SecondActivity extends Activity implements OnClickListener
{
    /** @author GTU MCA PPT, www.gtumcappt.com */
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button login = (Button)findViewById(R.id.btnlogin);
        Button clear = (Button)findViewById(R.id.btnclear);
        login.setOnClickListener(this);
        clear.setOnClickListener(this);
    }
    public void onClick(View v)
    {
     EditText username = (EditText)findViewById(R.id.txtusername);
     EditText password =(EditText)findViewById(R.id.txtpassword);
     if(v.getId()==R.id.btnlogin)
     {
if(username.getText().toString().equals("keval") && password.getText().toString().equals("nagaria"))
      {
       //Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
       Intent i = new Intent(this,S2.class);
       i.putExtra("username", username.getText().toString());
       startActivity(i);
      }
      else
      {
       Toast.makeText(this, "Error", Toast.LENGTH_LONG).show();
      }
     }
     if(v.getId()==R.id.btnclear)
     {
      username.setText("");
      password.setText("");
     }
    }
}

S2.java :

package kmn.Second;

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;

public class S2 extends Activity 
{
    /** @author GTU MCA PPT, www.gtumcappt.com */
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Intent i = getIntent();
        //Toast.makeText(this, "Welcome",Toast.LENGTH_LONG).show();
        String username=i.getStringExtra("username");       
        TextView tv=new TextView(this);
        Button btnBack = new Button(this);
        btnBack.setText("Back");
        tv.setText("Welcome "+username+" !");
        tv.setTextColor(Color.rgb(255, 255, 100));            
        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);
        
        btnBack.setOnClickListener(new Button.OnClickListener()
        {
         public void onClick(View v)
         {
          setContentView(R.layout.main);
         }        
        });
 }

}

Exercise : 1

Create “Hello World” application. That will display “Hello World” in the middle of the screen in the red color with white background.

Screen Shot:

XML :

main.xml :

JAVA :

FirstActivity.java :

import android.app.Activity;
import android.os.Bundle;
public class FirstActivity extends Activity 
{
    /** @author GTU MCA PPT, www.gtumcappt.com */
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
}

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