Android Can I use JOIN at mediastore query

浪子不回头ぞ 提交于 2019-11-29 12:11:22

But I think that you can use joins with content providers. If you make two queries, you can join them by using CursorJoiner. I am using it and it works good.

Snippet from Android docs:

CursorJoiner joiner = new CursorJoiner(cursorA, keyColumnsofA, cursorB, keyColumnsofB);
 for (CursorJointer.Result joinerResult : joiner) {
     switch (joinerResult) {
         case LEFT:
             // handle case where a row in cursorA is unique
             break;
         case RIGHT:
             // handle case where a row in cursorB is unique
             break;
         case BOTH:
             // handle case where a row with the same key is in both cursors
             break;
     }
 }

it is not exactly the same as SQL join but its useful. In each "case" you can manipulate with both cursors which are pointing to processed row.

is there any method to use join in a query at mediastore data?

There are no JOINs possible with content provider queries, sorry.

Or also is there any method to access the mediastore data through a database and not with the content provider?

Only if you write your own firmware.

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