Objective:
The goal of this lab is to download Android SDK file for the Eclipse and learn how to write a Android App, which is called MyFirstApp. and we had to follow the instructions that where given (http://developer.android.com/training/basics/firstapp/starting-activity.html).

Code:

package com.example.myfirstapp;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity {
	public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";

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

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
	/** Called when the user clicks the Send button */
	public void sendMessage(View view) {
	    Intent intent = new Intent(this, DisplayMessageActivity.class);
	    EditText editText = (EditText) findViewById(R.id.edit_message);
	    String message = editText.getText().toString();
	    intent.putExtra(EXTRA_MESSAGE, message);
	    startActivity(intent);
	}

}

package com.example.myfirstapp;

import android.os.Build;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.support.v4.app.NavUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

public class DisplayMessageActivity extends Activity 
{

    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Get the message from the intent
        Intent intent = getIntent();
        String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

        // Create the text view
        TextView textView = new TextView(this);
        textView.setTextSize(40);
        textView.setText(message);

        // Set the text view as the activity layout
        setContentView(textView);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case android.R.id.home:
            NavUtils.navigateUpFromSameTask(this);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Screenshot