Android Intent Tutorial

Intent is the message that is passed between components such as activities, content providers, broadcast receivers, services etc.
The dictionary meaning of intent is intention or purpose. So, it can be described as the intention to do action.
It is mainly used to:

Start the service
Launch an activity
Display a web page
Display a list of contacts
Broadcast a message
Dial a phone call etc.

Types of Intents

There are two types of intents in android: implicit and explicit.

Implicit Intent

Implicit Intent doesn't specifiy the component. In such case, intent provides information of available components provided by the system that is to be invoked.
For example, you may write the following code to view the webpage.

Intent intent=new Intent(Intent.ACTION_VIEW);  
intent.setData(Uri.parse("http://www.javatpoint.com"));  
startActivity(intent);  

Explicit Intent

Explicit Intent specifies the component. In such case, intent provides the external class to be invoked.

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

To get the full code of explicit intent, visit the next page.

Android Implicit Intent Example

Let's see the simple example of implicit intent that displays a web page.

activity_main.xml

File: activity_main.xml

<RelativeLayout xmlns:androclass="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=".MainActivity" >  
  
    <EditText  
        android:id="@+id/editText1"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignParentTop="true"  
        android:layout_centerHorizontal="true"  
        android:layout_marginTop="44dp"  
        android:ems="10" />  
  
    <Button  
        android:id="@+id/button1"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_below="@+id/editText1"  
        android:layout_centerHorizontal="true"  
        android:layout_marginTop="54dp"  
        android:text="Visit" />  
  
</RelativeLayout>  

Activity class

File: MainActivity.java

package org.sssit.implicitintent;  
  
import android.net.Uri;  
import android.os.Bundle;  
import android.app.Activity;  
import android.content.Intent;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.EditText;  
  
public class MainActivity extends Activity {  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
          
        final EditText editText1=(EditText)findViewById(R.id.editText1);  
        Button button1=(Button)findViewById(R.id.button1);  
          
        button1.setOnClickListener(new OnClickListener() {  
              
            @Override  
            public void onClick(View arg0) {  
                String url=editText1.getText().toString();  
                Intent intent=new Intent(Intent.ACTION_VIEW,Uri.parse(url));  
                startActivity(intent);  
            }  
        });  
    }  
  
}  