来自多个内容提供商的结果的游标 - Android

Question

I want to query two different content providers:

MediaStore.Images.Media.EXTERNAL_CONTENT_URI

and

MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI

First I need to query the "MediaStore.Images.Media.EXTERNAL_CONTENT_URI" so that I can get a cursor to all images that were added after a specific date. I know now how to do this. The problem is with the thumbnails. I also need to query the "MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI" for obtaining the thumbnail images so that I can show them in a listview. This is were I somehow need to combine the result from the two queries because I only want the Thumbnails for the Images that were added after a specific date. But the "MediaStore.Images.Thumbnails" doesn't have information about when the image was added. It only has an ID to the original image in "MediaStore.Images.Media".

So, to sum up what I need help with:

I need to get a cursor that contains the following columns:

MediaStore.Images.Thumbnails.IMAGE_ID,

MediaStore.Images.Thumbnails._ID,

MediaStore.Images.Thumbnails.DATA,

MediaStore.Images.Media.DATA,

MediaStore.Images.Media.DATE_TAKEN

How can this be done?

Thanks for help!

Answer 1

You can select the data from one provider, and select per row using a ViewBinder.

Within MyActivity.onCreate() {
...
cursorAdapter.setViewBinder(myViewBinder),
...
}

And somewhere you implement your ViewBinder like this...

private final ViewBinder myViewBinder=new ViewBinder() {
  @Override
  public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
    if(columnIndex==INDEX_OF_THUMB) {
      int id=cursor.get("_id");
      // get thumb-image data for id from somewhere
      // and display in view
    }
};

Hope this helps.

Answer 2

AFAIK，您将手动需要进行连接并将结果倒入MatrixCursor （如果您确定需要Cursor ）或其他一些数据结构。