Android Tutorial - Start an activity using intent object

Android Tutorial

We can start an activity with help of startActivity aka Intent. Activity extends with defining method on the context object. Here is a sample code to clearly show how to wakeup or start another activity with intent.

To start an activity, use the method startActivity(intent). This method is defined on theContext object which Activity extends. The following code demonstrates how you can start another activity via an intent.

Start the activity connect to the
specified class

Intent i = new Intent(this, ActivityTwo.class);
startActivity(i);

Subactivities are started by main activities. Activities with main thread are started by intent and subactivities are started by parent activities. Main activities are meant and subactivities are started by meant activities respectively.

Activities which are started by other Android activities are called subactivities. This wording makes it easier to describe which activity is meant.

In this tutorial we will learn How to Start New Activity On Button Click via Intent

Step 1 – Create new Android project

Step 2 – Add a button to main activity (layout/activity_main.xml) using designer.

Step 3 Add the new activity . Right Click Project -> New -> Activity -> Blank Activity

Give the name to your activity SecondActivity

Change the background color of SecondActivity if you wish.

write the following code

src/main/AndroidManifest.xml

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            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=".SecondActivity"
            android:label="@string/title_activity_second" >
            <intent-filter>
                <action android:name="com.example.programmingknowledge.thefirstapp.SecondActivity" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
    </application>

</manifest>

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Open Second Activity"
        android:id="@+id/button"
        android:layout_gravity="center_horizontal"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="62dp"
        android:layout_marginStart="62dp"
        android:layout_marginTop="205dp" />
</RelativeLayout>

layout/activity_second.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.programmingknowledge.thefirstapp.SecondActivity"
    android:background="#ff80ff3c">

</RelativeLayout>

com/example/programmingknowledge/thefirstapp/MainActivity.java

package com.example.programmingknowledge.thefirstapp;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

public class MainActivity extends ActionBarActivity {
      private static  Button button_sbm;
      @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
          OnClickButtonListener();
    }

    public void OnClickButtonListener() {
        button_sbm = (Button)findViewById(R.id.button);
        button_sbm.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Intent intent = new Intent("com.example.programmingknowledge.thefirstapp.SecondActivity");
                        startActivity(intent);
                    }
                }
        );

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

com/example/programmingknowledge/thefirstapp/SecondActivity.java

package com.example.programmingknowledge.thefirstapp;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;


public class SecondActivity extends ActionBarActivity {

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_second, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

OUTPUT: