ANDROID

Creating a simple android app with 2 buttons

How do I build a very simple android app you ask? It's easy, building a basic android application is not that hard. Making something really useful, cool and bug free, now that takes a good developer.
This is a brief tutorial will show you how to code a very basic two button android application (with a start button and a stop button).
You can use this code as an android project template or starting point for simple projects.

Two Button Application Use Case

A simple two button application, can be your starting point for various android projects. It can be useful for example when you have an application that starts and stops a service from the click of a button Watch for tutorial on this soon.
Note:This tutorial assumes you have completed the HelloWorld Tutorial in the Android docs and you are a little familiar with Eclipse and ADT. The tutorial is aimed at developers who are very new to Android.

Creating a two button app

1) Create the project

In Eclipse create a new Android project and define the properties as shown below. Feel free to use your own package names.

2) Create a simple layout

For our main activity we're going to define a very basic layout consisting of one TextView and two Buttons (a start button and a stop button).
Modify your project/res/layout/main.xml file to this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="This is a simple two button app. \r\n \r\n Tell your user what your app does here \r\n \r\n \r\n \r\n"
    android:padding="10dp"
    android:textColor="#FFFFFF"
    />
<Button
 android:id="@+id/buttonStart"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:text="Start"/>
<Button
 android:id="@+id/buttonStop"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:text="Stop"/>
</LinearLayout>

If you run your project in the emulator it should look like this

3) Adding onClickListeners to the buttons

In order for the buttons to actually do something useful, and to provide a template for where you can put future functionality, we'll need to define onClickListeners for each button.
Let's update the TwoButtonApp.java main activiy with the following code:

//package com.idleworx.android.twobuttonapp; need u r package add here 

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class TwoButtonApp extends Activity {
    
 private static String logtag = "TwoButtonApp";//for use as the tag when logging 
  
 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        Button buttonStart = (Button)findViewById(R.id.buttonStart);        
     buttonStart.setOnClickListener(startListener); // Register the onClick listener with the implementation above
      
     Button buttonStop = (Button)findViewById(R.id.buttonStop);        
     buttonStop.setOnClickListener(stopListener); // Register the onClick listener with the implementation above
    }
    
    //Create an anonymous implementation of OnClickListener
    private OnClickListener startListener = new OnClickListener() {
        public void onClick(View v) {
          Log.d(logtag,"onClick() called - start button");              
          Toast.makeText(TwoButtonApp.this, "The Start button was clicked.", Toast.LENGTH_LONG).show();
          Log.d(logtag,"onClick() ended - start button");
        }
    };
    
    // Create an anonymous implementation of OnClickListener
    private OnClickListener stopListener = new OnClickListener() {
        public void onClick(View v) {
         Log.d(logtag,"onClick() called - stop button"); 
         Toast.makeText(TwoButtonApp.this, "The Stop button was clicked.", Toast.LENGTH_LONG).show();
          Log.d(logtag,"onClick() ended - stop button");
        } 
    };
    
    
    @Override
 protected void onStart() {//activity is started and visible to the user
  Log.d(logtag,"onStart() called");
  super.onStart();  
 }
 @Override
 protected void onResume() {//activity was resumed and is visible again
  Log.d(logtag,"onResume() called");
  super.onResume();
  
 }
 @Override
 protected void onPause() { //device goes to sleep or another activity appears
  Log.d(logtag,"onPause() called");//another activity is currently running (or user has pressed Home)
  super.onPause();
  
 }
 @Override
 protected void onStop() { //the activity is not visible anymore
  Log.d(logtag,"onStop() called");
  super.onStop();
  
 }
 @Override
 protected void onDestroy() {//android has killed this activity
   Log.d(logtag,"onDestroy() called");
   super.onDestroy();
 }
}

Configure button Choose the type of button and set the appropriate width and height by changing the values of query parameters in line 4.