Creating a simple Behavior

To create a Behavior just extend the CoordinatorLayout.Behavior class.

Extend the CoordinatorLayout.Behavior

Example:

public class MyBehavior<V extends View> extends CoordinatorLayout.Behavior<V> {

      /**
       * Default constructor.
       */
      public MyBehavior() {
      }
    
      /**
       * Default constructor for inflating a MyBehavior from layout.
       *
       * @param context The {@link Context}.
       * @param attrs The {@link AttributeSet}.
       */
      public MyBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
      }
}

This behavior need to be attached to a child View of a CoordinatorLayout to be called.

Attach a Behavior programmatically

MyBehavior myBehavior = new MyBehavior();
CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) view.getLayoutParams();
params.setBehavior(myBehavior);

Attach a Behavior in XML

You can use the layout_behavior attribute to attach the behavior in XML:

<View
  android:layout_height="...."
  android:layout_width="...."
  app:layout_behavior=".MyBehavior" />

Attach a Behavior automatically

If you are working with a custom view you can attach the behavior using the @CoordinatorLayout.DefaultBehavior annotation:

@CoordinatorLayout.DefaultBehavior(MyBehavior.class)
public class MyView extends ..... {

}

Found a mistake? Have a question or improvement idea? Let me know.

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