ContextWrapperEdgeEffect.java

/*
 * Copyright (c) 2013 Android Alliance, LTD
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.marshalchen.common.uimodule.edgeeffectoverride;

import android.content.Context;
import android.content.ContextWrapper;
import android.content.res.AssetManager;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.graphics.PorterDuff;
import android.graphics.drawable.Drawable;
import android.util.DisplayMetrics;
import android.util.Log;
import com.marshalchen.common.uimodule.R;

public class ContextWrapperEdgeEffect extends ContextWrapper {

  private ResourcesEdgeEffect mResourcesEdgeEffect;
  private int mColor;
  private Drawable mEdgeDrawable;
  private Drawable mGlowDrawable;

  public ContextWrapperEdgeEffect(Context context) {
    this(context, 0);
  }

  public ContextWrapperEdgeEffect(Context context, int color) {
    super(context);
    mColor = color;
    Resources resources = context.getResources();
    mResourcesEdgeEffect = new ResourcesEdgeEffect(resources.getAssets(), resources.getDisplayMetrics(), resources.getConfiguration());
  }

  public void setEdgeEffectColor(int color) {
    mColor = color;
    if (mEdgeDrawable != null) mEdgeDrawable.setColorFilter(color, PorterDuff.Mode.MULTIPLY);
    if (mGlowDrawable != null) mGlowDrawable.setColorFilter(color, PorterDuff.Mode.MULTIPLY);
  }

  @Override
  public Resources getResources() {
    return mResourcesEdgeEffect;
  }

  private class ResourcesEdgeEffect extends Resources {
    private int overscroll_edge = getPlatformDrawableId("overscroll_edge");
    private int overscroll_glow = getPlatformDrawableId("overscroll_glow");

    public ResourcesEdgeEffect(AssetManager assets, DisplayMetrics metrics, Configuration config) {
      //super(metrics, localConfiguration);
      super(assets, metrics, config);
    }

    private int getPlatformDrawableId(String name) {
      try {
        int i = ((Integer) Class.forName("com.android.internal.R$drawable").getField(name).get(null)).intValue();
        return i;
      } catch (ClassNotFoundException e) {
        Log.e("[ContextWrapperEdgeEffect].getPlatformDrawableId()", "Cannot find internal resource class");
        return 0;
      } catch (NoSuchFieldException e1) {
        Log.e("[ContextWrapperEdgeEffect].getPlatformDrawableId()", "Internal resource id does not exist: " + name);
        return 0;
      } catch (IllegalArgumentException e2) {
        Log.e("[ContextWrapperEdgeEffect].getPlatformDrawableId()", "Cannot access internal resource id: " + name);
        return 0;
      } catch (IllegalAccessException e3) {
        Log.e("[ContextWrapperEdgeEffect].getPlatformDrawableId()", "Cannot access internal resource id: " + name);
      }
      return 0;
    }

    @Override
    public Drawable getDrawable(int resId) throws NotFoundException {
      Drawable ret = null;
      if (resId == this.overscroll_edge) {
        mEdgeDrawable = ContextWrapperEdgeEffect.this.getBaseContext().getResources().getDrawable(R.drawable.edge_effect_overscroll_edge);
        ret = mEdgeDrawable;
      } else if (resId == this.overscroll_glow) {
        mGlowDrawable = ContextWrapperEdgeEffect.this.getBaseContext().getResources().getDrawable(R.drawable.edge_effect_overscroll_glow);
        ret = mGlowDrawable;
      } else return super.getDrawable(resId);

      if (ret != null) {
        ret.setColorFilter(mColor, PorterDuff.Mode.MULTIPLY);
      }

      return ret;
    }
  }
}