| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * 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 android.content.res; |
| |
| import android.annotation.AnyRes; |
| |
| /** |
| * Provides a set of utility methods for dealing with Resource IDs. |
| * @hide |
| */ |
| public final class ResourceId { |
| |
| /** |
| * The {@code null} resource ID. |
| */ |
| public static final @AnyRes int ID_NULL = 0; |
| |
| /** |
| * Checks whether the integer {@code id} is a valid resource ID, as generated by AAPT. |
| * <p>Note that a negative integer is not necessarily an invalid resource ID, and custom |
| * validations that compare the {@code id} against {@code 0} are incorrect.</p> |
| * @param id The integer to validate. |
| * @return {@code true} if the integer is a valid resource ID. |
| */ |
| public static boolean isValid(@AnyRes int id) { |
| // With the introduction of packages with IDs > 0x7f, resource IDs can be negative when |
| // represented as a signed Java int. Some legacy code assumes -1 is an invalid resource ID, |
| // despite the existing documentation. |
| return id != -1 && (id & 0xff000000) != 0 && (id & 0x00ff0000) != 0; |
| } |
| } |