hack edge effect

DrawableColorHacker.java

package com.celink.common.ui;

import android.content.Context;
import android.graphics.PorterDuff;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;

import com.celink.common.util.SystemUtil;
import com.googfit.util.L;
import com.googfit.util.ThemeUtil;

/**
 * 通过改变Drawable的缓存状态, 实现改变所有图片的效果...
 * Created by JiangSong on 2015/12/30.
 */
public class DrawableColorHacker {
    private static DrawableColorHacker sEdgeHacker;
    private static DrawableColorHacker sGlowHacker;

    public static void hackEdgeEffect(Context context) {
        if (!SystemUtil.api21()) {
            try {
                if (sEdgeHacker == null) {
                    sEdgeHacker = new DrawableColorHacker(context.getResources().getIdentifier("overscroll_edge", "drawable", "android"));
                    sGlowHacker = new DrawableColorHacker(context.getResources().getIdentifier("overscroll_glow", "drawable", "android"));
                }
                sEdgeHacker.update(context, ThemeUtil.getThemeSkinColor(context));
                sGlowHacker.update(context, ThemeUtil.getThemeSkinColor(context));
            } catch (Exception e) {// 为防意外, try一下
                e.printStackTrace();
            }
        }
    }

    private int mId;
    private int mColor;
    private Drawable.ConstantState mState;

    public DrawableColorHacker(int id) {
        mId = id;
    }

    public void update(Context context, int color) {
        Drawable drawable = ContextCompat.getDrawable(context, mId);
        Drawable.ConstantState constantState = drawable.getConstantState();
        if (color != mColor || constantState != mState) {// 颜色/状态一个改变了, 则要更新ColorFilter
            drawable.setColorFilter(color, PorterDuff.Mode.SRC_ATOP);
            mColor = color;
            mState = drawable.getConstantState();
        } else {
            L.p("颜色和状态都没改变不需要更新ColorFilter");
        }
    }
}