Intent Tutorial
Android Intent is the message that is passed between components such as activities, content providers, broadcast receivers, services etc.
It is generally used with startActivity() method to invoke activity, broadcast receivers etc.
The dictionary meaning of intent is intention or purpose. So, it can be described as the intention to do action.
The LabeledIntent is the subclass of android.content.Intent class.
Android intents are 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 Android Intents
There are two types of intents in android: implicit and explicit.
1) 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.setData(Uri.parse("http://www.javatpoint.com"));
startActivity(intent);
2) Explicit Intent
Explicit Intent specifies the component. In such case, intent provides the external class to be invoked.
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
<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="example.javatpoint.com.implicitintent.MainActivity">
<EditText
android:id="@+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="60dp"
android:ems="10"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.575"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="8dp"
android:layout_marginLeft="156dp"
android:layout_marginTop="172dp"
android:text="Visit"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editText" />
</android.support.constraint.ConstraintLayout>
Activity class
File: MainActivity.java
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
Button button;
EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = findViewById(R.id.button);
editText = findViewById(R.id.editText);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String url=editText.getText().toString();
Intent intent=new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(intent);
}
});
}
}
Output:
