Simple Android Program for Switch From One Activity to Another -

Switch from one activity to another in terms of android means moving from one android screen to another. For example we login to a particular application and click on the login button, it shows a new page(screen). A simple example of these kind of android program is given below.

open Android studio. Create a new project

File-> New->New Project, Give project name, select target android devices, select empty activity, give activity_name and layout name or leave it as default.

here MainActivity.java is your activity name and activity_main is your layout name. And it is default.

create a new activity:

File->New->Activity->Empty Activity
give activity name as SecondActivity
give layout name as new_layout

Now do the following

MainActivity.java

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import static com.example.mca.myapplication.R.*;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

Button b1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(layout.activity_main); //layout associated with this activity
b1=(Button)findViewById(R.id.bt1);/* id of the button from layout identified and
passed to button object b1*/
b1.setOnClickListener(this); //Listen to the click action of the button in layout
}

@Override
public void onClick(View v) {
Intent i = new Intent(this,SecondActivity.class);/* when button clicked, Intent
created which helps to move from one activity to another*/
startActivity(i); //Intent started
}
}

SecondActivity.java

package com.example.mca.myapplication;

import android.os.Bundle;


public class SecondActivity extends MainActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_layout);

}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Next!"
android:id="@+id/bt1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

new_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="welcome to second activity"/>

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mca.myapplication">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<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=".SecondActivity" >
</activity>
</application>

</manifest>

Note:- When ever a new activity is added to your project, it must be entered in Android Manifest file. For that, use <activity> tag same as the above code.