Android Intent Tutorial for Beginners

Android Intent :

Intent has many uses like it is used to startActivity, services, different Broadcast intents which we will be covering in our coming tutorials.In this Android Tutorial on Intent we will be looking how to start a activity using intent in android.

In android apps generally user have to move through different screens as a part of app functionality.Clicking on a button will move us from one screen to another but we need to know how the coding is done for it.

We will see how the user moves from one screen to another what’s the programming involved. Before moving from one screen to another set both the screens with buttons to move to another screen and return back.

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

This line of code will make you start the intent which will result in screen move from main screen to second screen on clicking the button in first screen.

startActivity(i);

will start the Android Intent.

This is the most basic tutorial when you start android app development and as you progress you will learn a lot in handling the Android Intent through out your app.

Android Intent Video:

MainActivity.java :

This is the implementation code for android intent hope you have gone through the above video tutorial before getting started.

public class MainActivity extends Activity {

	Button firstbut;

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

		firstbut = (Button) findViewById(R.id.firstbut);

		firstbut.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {

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

			}
		});

	}

In firstscreen.xml add a textview and button. Clicking on button user moves to another screen.

firstscreen.xml

<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.androidcoding.abhi.intent.MainActivity" >

    <TextView
        android:id="@+id/firsttitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="First Screen"
        android:layout_marginTop="150dp"
        android:layout_gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <Button
        android:id="@+id/firstbut"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:layout_gravity="center"
        android:text="Move to next screen" />

</LinearLayout>

Now declare our Second activity i.e., SecondActivity.java under src.

SecondActivity.java

public class SecondActivity extends Activity{

	Button secondbut;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.secondscreen);

		secondbut = (Button) findViewById(R.id.secondbut);

		secondbut.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {

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

			}
		});

	}

secondscreen.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"
    android:orientation="vertical" >

     <TextView
        android:id="@+id/secondtitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Second Screen"
        android:layout_marginTop="150dp"
        android:layout_gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <Button
        android:id="@+id/secondbut"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:layout_gravity="center"
        android:text="Back" />

</LinearLayout

Note :

Now we have to declare our second activity in manifest file so that when we try to move it second screen should be initiated in manifest file.

Now add second screen to Android Manifest file

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.androidcoding.abhi.intent"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.androidcoding.abhi.intent.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="com.androidcoding.abhi.intent.SecondActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>