Android MediaStore中的BUCKET_ID是什么？

我浏览了一些查询MediaStore.Images内容提供商并使用名为BUCKET_ID的列的代码：

Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
String projection[] = {
    "DISTINCT " + MediaStore.Images.Media.BUCKET_DISPLAY_NAME,
    MediaStore.Images.Media.BUCKET_ID,
    MediaStore.Images.Media.DATE_TAKEN,
    MediaStore.Images.Media.DATA
};
String BUCKET_GROUP_BY = "1) GROUP BY 1,(2";
String BUCKET_ORDER_BY = "MAX(datetaken) DESC";
Cursor imagecursor = getContentResolver().query(uri, projection, BUCKET_GROUP_BY, null, BUCKET_ORDER_BY);

一般来说，这些列代表什么？有人能举例说明吗？文档中关于这些列的一行代码解释得很少

BUCKET\u DISPLAY\u NAME

添加到API级别29 字符串存储桶\u显示\u名称 存储桶显示图像的名称。这是从数据列自动计算的只读属性

类型：文本

常量值：bucket\u display\u name

桶号

在API级别29中添加 字符串BUCKET\u ID 映像的存储桶id。这是从数据列自动计算的只读属性

类型：文本

常量值：bucket\u id

拍摄日期

添加到API级别29 字符串日期 自1970年1月1日以来以毫秒为单位拍摄图像的日期和时间

类型：整数

常量值：已获取日期

存储桶\u显示\u名称

添加到API级别29 字符串存储桶\u显示\u名称 存储桶显示图像的名称。这是从数据列自动计算的只读属性

类型：文本

常量值：bucket\u display\u name

桶号

在API级别29中添加 字符串BUCKET\u ID 映像的存储桶id。这是从数据列自动计算的只读属性

类型：文本

常量值：bucket\u id

拍摄日期

添加到API级别29 字符串日期 自1970年1月1日以来以毫秒为单位拍摄图像的日期和时间

类型：整数

---

常量值：日期记录的文档对此非常不清楚，上面的答案是文档的复制粘贴。无论如何，我已经从以下评论中找到了答案：

    // BUCKET_DISPLAY_NAME is a string like "Camera" which is the directory
    // name of where an image or video is in. BUCKET_ID is a hash of the path
    // name of that directory (see computeBucketValues() in MediaProvider for
    // details). MEDIA_TYPE is video, image, audio, etc.
    //
    // The "albums" are not explicitly recorded in the database, but each image
    // or video has the two columns (BUCKET_ID, MEDIA_TYPE). We define an
    // "album" to be the collection of images/videos which have the same value
    // for the two columns.

以下是computeBucketValues供参考：

/**
     * @param data The input path
     * @param values the content values, where the bucked id name and bucket display name are updated.
     *
     */
    private static void computeBucketValues(String data, ContentValues values) {
        File parentFile = new File(data).getParentFile();
        if (parentFile == null) {
            parentFile = new File("/");
        }

        // Lowercase the path for hashing. This avoids duplicate buckets if the
        // filepath case is changed externally.
        // Keep the original case for display.
        String path = parentFile.toString().toLowerCase();
        String name = parentFile.getName();

        // Note: the BUCKET_ID and BUCKET_DISPLAY_NAME attributes are spelled the
        // same for both images and video. However, for backwards-compatibility reasons
        // there is no common base class. We use the ImageColumns version here
        values.put(ImageColumns.BUCKET_ID, path.hashCode());
        values.put(ImageColumns.BUCKET_DISPLAY_NAME, name);
}

---

文档对此非常不清楚，上面的答案是文档的复制粘贴。无论如何，我已经从以下评论中找到了答案：

    // BUCKET_DISPLAY_NAME is a string like "Camera" which is the directory
    // name of where an image or video is in. BUCKET_ID is a hash of the path
    // name of that directory (see computeBucketValues() in MediaProvider for
    // details). MEDIA_TYPE is video, image, audio, etc.
    //
    // The "albums" are not explicitly recorded in the database, but each image
    // or video has the two columns (BUCKET_ID, MEDIA_TYPE). We define an
    // "album" to be the collection of images/videos which have the same value
    // for the two columns.

以下是computeBucketValues供参考：

/**
     * @param data The input path
     * @param values the content values, where the bucked id name and bucket display name are updated.
     *
     */
    private static void computeBucketValues(String data, ContentValues values) {
        File parentFile = new File(data).getParentFile();
        if (parentFile == null) {
            parentFile = new File("/");
        }

        // Lowercase the path for hashing. This avoids duplicate buckets if the
        // filepath case is changed externally.
        // Keep the original case for display.
        String path = parentFile.toString().toLowerCase();
        String name = parentFile.getName();

        // Note: the BUCKET_ID and BUCKET_DISPLAY_NAME attributes are spelled the
        // same for both images and video. However, for backwards-compatibility reasons
        // there is no common base class. We use the ImageColumns version here
        values.put(ImageColumns.BUCKET_ID, path.hashCode());
        values.put(ImageColumns.BUCKET_DISPLAY_NAME, name);
}

---

这是从文档复制粘贴！请补充一些解释。正如Manish提到的，这些数据在文档中很容易获得。这是从文档复制粘贴！请补充一些解释。正如Manish所提到的，这些数据在文档中很容易获得。很棒的工作。这些应该是文件，而不是谷歌的伟大工作。这些应该是doc，而不是@Google