onBackPressed Android

The onBackPressed method is a callback method provided by the Android framework to handle the back button press event. It allows developers to define specific actions that should be taken when the user presses the back button on an Android device.

Syntax

@Override
public void onBackPressed() {
    // Define actions to be taken on back button press
}

Usage

The onBackPressed method is typically overridden in an Activity or a Fragment to control the behavior of the back button within the respective screen or fragment. It is important to note that this method is only available in classes that extend Activity or Fragment.

The purpose of this method is to intercept the back button press and perform custom actions. By default, pressing the back button will simply close the current activity or fragment and return to the previous one. However, by implementing onBackPressed, you can define how the back button should behave in your application.

Example

Suppose you have an Activity called MainActivity and you want to display a toast message when the back button is pressed:

public class MainActivity extends AppCompatActivity {
    ...

    @Override
    public void onBackPressed() {
        Toast.makeText(this, "Back button pressed", Toast.LENGTH_SHORT).show();
        super.onBackPressed();
    }
}

In this example, when the back button is pressed, a toast message with the text "Back button pressed" will be displayed for a short duration. Additionally, the super.onBackPressed() line indicates that the default behavior should still be executed after our custom actions are performed.

The onBackPressed method can also be used to navigate to a specific fragment, display a confirmation dialog before exiting the activity, or any other desired behavior.

Overall, onBackPressed is a powerful method that allows developers to control the back button behavior in Android applications, providing a flexible and customizable user experience.