“Counter” application demo

Create main.xml

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

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

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="@string/hello"

        android:textSize="30dp"

        android:gravity="center"

        android:layout_gravity="center"/>

    <Button

        android:id="@+id/Add"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:layout_marginTop="30dp"

        android:text="Add"

        android:layout_gravity="center"/>

    <Button

        android:id="@+id/button2"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="Substract"

        android:layout_marginTop="50dp"

        android:layout_gravity="center_horizontal"/>

</LinearLayout>

Create Main.java

package com.example.FirstProject;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class FirstProjectActivity extends Activity {

       int counter;

       Button add,sub;

       TextView display;

      

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              // TODO Auto-generated method stub

              super.onCreate(savedInstanceState);

              setContentView(R.layout.main);

      

        counter=0;

        add=(Button)findViewById(R.id.Add);

        sub=(Button)findViewById(R.id.button2);

        display=(TextView)findViewById(R.string.hello);

      

        add.setOnClickListener(new OnClickListener() {

                           // TODO Auto-generated method stub

                           counter++;

                           display.setText("Total is: " + counter);

                     }

              });

        sub.setOnClickListener(new OnClickListener() {              

                     public void onClick(View v) {

                           // TODO Auto-generated method stub

                           counter--;

                           display.setText("Total is: " + counter);

                     }

              });

    }

   

}

Android Maiifest.xml

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

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

    package="com.prince.FirstProject"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <application

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name" >

        <activity

            android:label="@string/app_name"

            android:name=".FirstProjectActivity" >

            <intent-filter >

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

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

            </intent-filter>

        </activity>

    </application>

</manifest>