How to switch between Activities in Android Tutorial

In thisnAndroid tutorial you learn how can nn activity is represent a single screen. Maximum applications have multiple activities to represent changed screens, for example, one activity to display a list of the application settings, a new activity to display the application status.


Create XML Layouts


javatportal/layout/main.xml

						 
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="I'm screen 2 (main2.xml)"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

javatportal/layout/main1.xml

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="I'm screen 1 (main.xml)"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <Button
        android:id="@+id/button1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Click me to another screen" />

</LinearLayout>

Create two activity classes

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

 Intent intent = new Intent(context, anotherActivity.class);
    startActivity(intent); 

DemoActivity.java

 package com.javatportal.android;

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

public class AppActivity extends Activity {

	Button button;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		addListenerOnButton();
	}

	public void addListenerOnButton() {

		final Context context = this;

		button = (Button) findViewById(R.id.button1);

		button.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {

			    Intent intent = new Intent(context, App2Activity.class);
                            startActivity(intent);   

			}

		});

	}

}

Demo2Activity.java

 package com.javatportal.android;

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

public class App2Activity extends Activity {

	Button button;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main2);
	}

}

AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.javatportal.android"
    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=".AppActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:label="@string/app_name"
            android:name=".App2Activity" >
        </activity>
    </application>

</manifest>