Android：如何查詢桶名稱列表

Question

我只想檢索桶（相冊）的名稱。例如。相機，下載等，但不是所有照片中的相機，下載等列表，那麼如何爲每個存儲桶名稱檢索一行？

我在畫廊應用程序中的意思是，您首先有相冊，例如，相機。當你點擊它時，它會顯示相機的所有照片。

我可以使用查詢的Where子句查詢Camera Roll中的照片。但是如果我只想要每張專輯名稱而不是照片的名稱，是否可以查詢？如果我查詢所有照片並且每組照片只取一行，那麼這將是耗時的。

請幫助

Answer 1

您可以查詢MediaStore.Images.Media.BUCKET_DISPLAY_NAME它。 Peter Knego sent a good example.這是一個很好的例子，您可以使用ContentResolver對象的query（）而不是棄用的managedQuery（）來更新它。

// 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

我有同樣的問題，這裏是我的解決方案（跟蹤庫源代碼之後），以獲得專輯名稱，並在它的第一個圖像（可作爲縮略圖使用這張專輯）：

（注那個桶重複由&命令技術刪除）

// 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

這是它。它爲我工作：

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的是含有專輯名稱

imageUrls ArrayList的是含有專輯的最後改性瀝青形象的路徑，你可以使用它作爲縮略圖

Answer 4

不要在如下查詢投影：

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