Android Activity Demo With Source Code

Android Activity – From One Screen To Another Screen

In Android, an activity is represent a single screen. Most applications have multiple activities to represent different screens, for example, one activity to display a list of the application settings, another activity to display the application status.

In this tutorial, we show you how to interact with activity, when a button is clicked, navigate from current screen (current activity) to another screen (another activity).

1. XML Layouts

Create following two XML layout files in “res/layout/” folder :

1. res/layout/main.xml – Represent screen 1
2. res/layout/main2.xml – Represent screen 2

File : res/layout/main.xml

<?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:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:text="This is First Screen" android:layout_width="wrap_content" android:id="@+id/textView1"></TextView>
<Button android:id="@+id/button1" android:layout_marginLeft="100dp" android:layout_marginTop="100dp" android:layout_height="wrap_content" android:text="Click Me" android:layout_width="wrap_content"></Button>
</LinearLayout>  

File : res/layout/main2.xml 

<?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:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:text="This is Second Screen" android:layout_width="wrap_content" android:id="@+id/textView1"></TextView>
    
</LinearLayout>

2. Activities

Create two activity classes :

HelloAndroidActivity.java –> main.xml
Button2.java –> main2.xml


To navigate from one screen to another screen, use following code :


    Intent intent = new Intent(context, anotherActivity.class);
    startActivity(intent);
File : HelloAndroidActivity.java
package com.helloexample;




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;

public class HelloAndroidActivity extends Activity implements  OnClickListener{
 
 private Button btn;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button)findViewById(R.id.button1);
        btn.setOnClickListener(this);
        
    }
    public void onClick(View v) {
  Intent i;
  switch (v.getId()) {
  case R.id.button1:
   i = new Intent(HelloAndroidActivity.this, Button2.class);
   
   startActivity(i);
   break;
  
  default:
   break;
  }
 }

}
File : Button2.java
package com.helloexample;

import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;

public class Button2 extends Activity {
 
 private Button btn;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);
       
    }
    }

3. AndroidManifest.xml

Declares above two activity classes in AndroidManifest.xml.

File : AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.helloexample"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="7" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".HelloAndroidActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
         <activity android:name=".Button2"
                  android:label="@string/app_name">
            
        </activity>
        

    </application>
</manifest>

4. Demo

Run application.

AppActivity.java (main.xml) screen is display.





When above button is clicked, it will navigate to another screen  (main2.xml).