RippleUtil.java

package com.vansuita.materialabout.util;

import android.content.res.ColorStateList;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.RippleDrawable;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.StateListDrawable;
import android.graphics.drawable.shapes.RoundRectShape;
import android.os.Build;
import android.util.StateSet;
import android.view.View;

import java.util.Arrays;

/**
 * Created by jrvansuita on 10/02/17.
 */

public final class RippleUtil {

    public static void background(View v, Drawable d) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
            v.setBackgroundDrawable(d);
        } else {
            v.setBackground(d);
        }
    }

    public static void background(View v, Bitmap b) {
        background(v, new BitmapDrawable(v.getResources(), b));
    }

    public static void backgroundRipple(View v, int color) {
        RippleUtil.background(v, getAdaptiveRippleDrawable(color));
    }

    public static Drawable getAdaptiveRippleDrawable(
            int normalColor) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            return new RippleDrawable(ColorStateList.valueOf(darker(normalColor)), getRippleMask(normalColor), null);
        } else {
            return getStateListDrawable(normalColor, darker(normalColor));
        }
    }

    private static Drawable getRippleMask(int color) {
        float[] outerRadii = new float[8];
        // 3 is radius of final ripple,
        // instead of 3 you can give required final radius
        Arrays.fill(outerRadii, 3);

        RoundRectShape r = new RoundRectShape(outerRadii, null, null);
        ShapeDrawable shapeDrawable = new ShapeDrawable(r);
        shapeDrawable.getPaint().setColor(color);

        return shapeDrawable;
    }

    private static StateListDrawable getStateListDrawable(
            int normalColor, int pressedColor) {
        StateListDrawable states = new StateListDrawable();
        states.addState(new int[]{android.R.attr.state_pressed},
                new ColorDrawable(pressedColor));
        states.addState(new int[]{android.R.attr.state_focused},
                new ColorDrawable(pressedColor));
        states.addState(new int[]{android.R.attr.state_activated},
                new ColorDrawable(pressedColor));
        states.addState(new int[]{}, new ColorDrawable(normalColor));
        states.addState(StateSet.WILD_CARD, new ColorDrawable(normalColor));
        return states;
    }

    public static int darker(int color) {
        int r = Color.red(color);
        int b = Color.blue(color);
        int g = Color.green(color);

        return Color.rgb((int) (r * .9), (int) (g * .9), (int) (b * .9));
    }

    public static boolean isDark(int color) {
        double darkness = 1 - (0.299 * Color.red(color) + 0.587 * Color.green(color) + 0.114 * Color.blue(color)) / 255;
        return !(darkness < 0.5 || color == 0);
    }
}