Android - Movable/Draggable Floating Action Button (FAB)

Question

I am using a FloatingActionButton in my app. Occasionally, it overlaps essential content, so I would like to make it so the user can drag the FAB out of the way.

No

Answer 1

Based on @ban-geoengineering answer I updated as perform ripple effect and left and right gravity like faceebook chat bubble. I created custom click listener cuz if consume touch event inside this code block, ripple effect doesnt work clearly.

package com.sample;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.OvershootInterpolator;

import com.google.android.material.floatingactionbutton.FloatingActionButton;

public class DraggableFloatingActionButton extends FloatingActionButton implements View.OnTouchListener {
    CustomClickListener customClickListener;

    private final static float CLICK_DRAG_TOLERANCE = 10; // Often, there will be a slight, unintentional, drag when the user taps the FAB, so we need to account for this.

    private float downRawX, downRawY;
    private float dX, dY;

    int viewWidth;
    int viewHeight;

    int parentWidth;
    int parentHeight;

    float newX;
    float newY;

    public DraggableFloatingActionButton(Context context) {
        super(context);
        init();
    }

    public DraggableFloatingActionButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public DraggableFloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {

        ViewGroup.MarginLayoutParams layoutParams = (ViewGroup.MarginLayoutParams) view.getLayoutParams();

        int action = motionEvent.getAction();
        if (action == MotionEvent.ACTION_DOWN) {

            downRawX = motionEvent.getRawX();
            downRawY = motionEvent.getRawY();
            dX = view.getX() - downRawX;
            dY = view.getY() - downRawY;

            return false; // not Consumed for ripple effect

        } else if (action == MotionEvent.ACTION_MOVE) {

            viewWidth = view.getWidth();
            viewHeight = view.getHeight();

            View viewParent = (View) view.getParent();
            parentWidth = viewParent.getWidth();
            parentHeight = viewParent.getHeight();

            newX = motionEvent.getRawX() + dX;
            newX = Math.max(layoutParams.leftMargin, newX); // Don't allow the FAB past the left hand side of the parent
            newX = Math.min(parentWidth - viewWidth - layoutParams.rightMargin, newX); // Don't allow the FAB past the right hand side of the parent

            newY = motionEvent.getRawY() + dY;
            newY = Math.max(layoutParams.topMargin, newY); // Don't allow the FAB past the top of the parent
            newY = Math.min(parentHeight - viewHeight - layoutParams.bottomMargin, newY); // Don't allow the FAB past the bottom of the parent

            view.animate()
                    .x(newX)
                    .y(newY)
                    .setDuration(0)
                    .start();

            return true; // Consumed

        } else if (action == MotionEvent.ACTION_UP) {

            float upRawX = motionEvent.getRawX();
            float upRawY = motionEvent.getRawY();

            float upDX = upRawX - downRawX;
            float upDY = upRawY - downRawY;

            if (newX > ((parentWidth - viewWidth - layoutParams.rightMargin) / 2)) {
                newX = parentWidth - viewWidth - layoutParams.rightMargin;
            } else {
                newX = layoutParams.leftMargin;
            }

            view.animate()
                    .x(newX)
                    .y(newY)
                    .setInterpolator(new OvershootInterpolator())
                    .setDuration(300)
                    .start();

            if (Math.abs(upDX) < CLICK_DRAG_TOLERANCE && Math.abs(upDY) < CLICK_DRAG_TOLERANCE) { // A click
                if (customClickListener != null) {
                    customClickListener.onClick(view);
                }
                return false;// not Consumed for ripple effect
            } else { // A drag
                return false; // not Consumed for ripple effect
            }

        } else {
            return super.onTouchEvent(motionEvent);
        }

    }

    public void setCustomClickListener(CustomClickListener customClickListener) {
        this.customClickListener = customClickListener;
    }

    public interface CustomClickListener {
        void onClick(View view);
    }

}