Android：如何查询桶名称列表

Question

我只想检索桶（相册）的名称。例如。相机，下载等，但不是所有照片中的相机，下载等列表，那么如何为每个存储桶名称检索一行？

我在画廊应用程序中的意思是，您首先有相册，例如，相机。当你点击它时，它会显示相机的所有照片。

我可以使用查询的Where子句查询Camera Roll中的照片。但是如果我只想要每张专辑名称而不是照片的名称，是否可以查询？如果我查询所有照片并且每组照片只取一行，那么这将是耗时的。

请帮助

Answer 1

您可以查询MediaStore.Images.Media.BUCKET_DISPLAY_NAME它。 Peter Knego sent a good example.这是一个很好的例子，您可以使用ContentResolver对象的query（）而不是弃用的managedQuery（）来更新它。

// which image properties are we querying 
String[] projection = new String[]{ 
     MediaStore.Images.Media._ID, 
     MediaStore.Images.Media.BUCKET_DISPLAY_NAME, 
     MediaStore.Images.Media.DATE_TAKEN 
}; 

// Get the base URI for the People table in the Contacts content provider. 
Uri images = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; 

// Make the query. 
ContentResolver cr = getContentResolver(); 
Cursor cur = cr.query(images, 
     projection, // Which columns to return 
     "",   // Which rows to return (all rows) 
     null,  // Selection arguments (none) 
     ""   // Ordering 
     ); 

Log.i("ListingImages"," query count="+cur.getCount()); 

if (cur.moveToFirst()) { 
    String bucket; 
    String date; 
    int bucketColumn = cur.getColumnIndex(
     MediaStore.Images.Media.BUCKET_DISPLAY_NAME); 

    int dateColumn = cur.getColumnIndex(
     MediaStore.Images.Media.DATE_TAKEN); 

    do { 
     // Get the field values 
     bucket = cur.getString(bucketColumn); 
     date = cur.getString(dateColumn); 

     // Do something with the values. 
     Log.i("ListingImages", " bucket=" + bucket 
       + " date_taken=" + date); 
    } while (cur.moveToNext()); 

} 

Answer 2

我有同样的问题，这里是我的解决方案（跟踪库源代码之后），以获得专辑名称，并在它的第一个图像（可作为缩略图使用这张专辑）：

（注那个桶重复由&命令技术删除）

// which image properties are we querying 
    String[] PROJECTION_BUCKET = { 
      ImageColumns.BUCKET_ID, 
      ImageColumns.BUCKET_DISPLAY_NAME, 
      ImageColumns.DATE_TAKEN, 
      ImageColumns.DATA}; 
    // We want to order the albums by reverse chronological order. We abuse the 
    // "WHERE" parameter to insert a "GROUP BY" clause into the SQL statement. 
    // The template for "WHERE" parameter is like: 
    // SELECT ... FROM ... WHERE (%s) 
    // and we make it look like: 
    // SELECT ... FROM ... WHERE (1) GROUP BY 1,(2) 
    // The "(1)" means true. The "1,(2)" means the first two columns specified 
    // after SELECT. Note that because there is a ")" in the template, we use 
    // "(2" to match it. 
    String BUCKET_GROUP_BY = 
      "1) GROUP BY 1,(2"; 
    String BUCKET_ORDER_BY = "MAX(datetaken) DESC"; 

    // Get the base URI for the People table in the Contacts content provider. 
    Uri images = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; 

    Cursor cur = getContentResolver().query(
      images, PROJECTION_BUCKET, BUCKET_GROUP_BY, null, BUCKET_ORDER_BY); 

    Log.i("ListingImages"," query count=" + cur.getCount()); 

    if (cur.moveToFirst()) { 
     String bucket; 
     String date; 
     String data; 
     int bucketColumn = cur.getColumnIndex(
       MediaStore.Images.Media.BUCKET_DISPLAY_NAME); 

     int dateColumn = cur.getColumnIndex(
       MediaStore.Images.Media.DATE_TAKEN); 
     int dataColumn = cur.getColumnIndex(
       MediaStore.Images.Media.DATA); 

     do { 
      // Get the field values 
      bucket = cur.getString(bucketColumn); 
      date = cur.getString(dateColumn); 
      data = cur.getString(dataColumn); 

      // Do something with the values. 
      Log.i("ListingImages", " bucket=" + bucket 
        + " date_taken=" + date 
        + " _data=" + data); 
     } while (cur.moveToNext()); 
    } 

Answer 3

这是它。它为我工作：

Uri images = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; 
    String[] projection = new String[]{ 
      MediaStore.Images.Media.BUCKET_ID, 
      MediaStore.Images.Media.BUCKET_DISPLAY_NAME, 
      MediaStore.Images.Media.DATE_TAKEN, 
      MediaStore.Images.Media.DATA 
    }; 

    String BUCKET_ORDER_BY = MediaStore.Images.Media.DATE_MODIFIED + " DESC"; 
    String BUCKET_GROUP_BY = "1) GROUP BY 1,(2"; 
    Cursor imagecursor = managedQuery(images, 
      projection, // Which columns to return 
      BUCKET_GROUP_BY,  // Which rows to return (all rows) 
      null,  // Selection arguments (none) 
      BUCKET_ORDER_BY  // Ordering 
      ); 

    this.imageUrls = new ArrayList<String>(); 
    this.imageBuckets = new ArrayList<String>(); 
    for (int i = 0; i < imagecursor.getCount(); i++) 
    { 
     imagecursor.moveToPosition(i); 
     int bucketColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.BUCKET_DISPLAY_NAME); 
     String bucketDisplayName = imagecursor.getString(bucketColumnIndex); 
     imageBuckets.add(bucketDisplayName); 
     int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA); 
     imageUrls.add(imagecursor.getString(dataColumnIndex)); 

    } 

imageBuckets ArrayList的是含有专辑名称

imageUrls ArrayList的是含有专辑的最后改性沥青形象的路径，你可以使用它作为缩略图

Answer 4

不要在如下查询投影：

String bucketProjection[] = {"Distinct "+ MediaStore.Images.Media.BUCKET_DISPLAY_NAME};