ResourceDrawableIdHelper.java

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.react.views.imagehelper;

import javax.annotation.Nullable;

import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.net.Uri;

/**
 * Helper class for obtaining information about local images.
 */
public class ResourceDrawableIdHelper {

  private Map<String, Integer> mResourceDrawableIdMap;

  private static final String LOCAL_RESOURCE_SCHEME = "res";
  private static ResourceDrawableIdHelper sResourceDrawableIdHelper;

  private ResourceDrawableIdHelper() {
    mResourceDrawableIdMap = new HashMap<String, Integer>();
  }

  public static ResourceDrawableIdHelper getInstance() {
    if (sResourceDrawableIdHelper == null) {
      sResourceDrawableIdHelper = new ResourceDrawableIdHelper();
    }
    return sResourceDrawableIdHelper;
  }

  public void clear() {
    mResourceDrawableIdMap.clear();
  }

  public int getResourceDrawableId(Context context, @Nullable String name) {
    if (name == null || name.isEmpty()) {
      return 0;
    }
    name = name.toLowerCase().replace("-", "_");
    if (mResourceDrawableIdMap.containsKey(name)) {
      return mResourceDrawableIdMap.get(name);
    }
    int id = context.getResources().getIdentifier(
        name,
        "drawable",
        context.getPackageName());
    mResourceDrawableIdMap.put(name, id);
    return id;
  }

  public @Nullable Drawable getResourceDrawable(Context context, @Nullable String name) {
    int resId = getResourceDrawableId(context, name);
    return resId > 0 ? context.getResources().getDrawable(resId) : null;
  }

  public Uri getResourceDrawableUri(Context context, @Nullable String name) {
    int resId = getResourceDrawableId(context, name);
    return resId > 0 ? new Uri.Builder()
        .scheme(LOCAL_RESOURCE_SCHEME)
        .path(String.valueOf(resId))
        .build() : Uri.EMPTY;
  }
}