SQLite Query returns null

问题:

What I've done

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I have a Gridview which is filled over my Database with the imageID's. Now I setted up a onItemClickListner with that I get the imageID -> this works!. Now I'd like to search my DB with that imageID, but it allways returns "null", but that shouldn't be because if filled my DB exactly with those imageID's. The Structure of the Table is that: RowID | SOURCE | INFO In Info i stored the imageID's

Question

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How do I have to change Cursor that I can get the entries over INFO. Down here you find the Code of my Cursor:

Code:

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    //Es wird nach der ID des smiley gesucht.
    public Cursor getSmiley(String info) throws SQLException {

        Cursor mCursor =

        this.mDb.query(true, DATABASE_TABLE, new String[] { INFO, SOURCE,
                }, INFO + "=" + info, null, null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }

How I get the imageID-back

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    public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
    Toast.makeText(SFilterConfigActivity.this, "" + position, Toast.LENGTH_SHORT).show();


    //Hier wird herrausgefunden welche ID das Bild hat und in den jeweiligen String gespeichert
    source = String.valueOf(v.getId());
    Log.v("IMAGEID", source);
    SmileyHelper.open();

    Cursor c = SmileyHelper.getSmiley(source);
    startManagingCursor(c);

        if (c != null){
            String size = String.valueOf(c.getCount());
            Log.v("WhatsInC", size);
        }


    if (c.moveToFirst()) { 
        do { 
        text = c.getString(c.getColumnIndex(SmileyDBAdapter.SOURCE));
        Log.v("WHATINTEXT", text);
        smiley = c.getString(c.getColumnIndex(SmileyDBAdapter.INFO)); 
        Log.v("WHATINSMILEY", smiley);
        } while (c.moveToNext());
    SmileyHelper.close();

---

Additional Information:

1. WhatIsInC, returns "0".

If you need more Code, just tell me Thx for your help in advance! Best Regards safari

回答1:

public Cursor getEmpByDept(String Dept)
  {
   SQLiteDatabase db=this.getReadableDatabase();
   String [] columns=new String[]{"_id",colName,colAge,colDeptName};
   Cursor c=db.query(viewEmps, columns, colDeptName+"=?", 
    new String[]{Dept}, null, null, null);
   return c;
  }

The db.query has the following parameters:

 1.String Table Name: The name of the table to run the query against
 2.String [ ] columns: The projection of the query, i.e., the columns to retrieve
 3.String WHERE clause: where clause, if none pass null
 4.String [ ] selection args: The parameters of the WHERE clause
 5.String Group by: A string specifying group by clause
 6.String Having: A string specifying HAVING clause
 7.String Order By by: A string Order By by clause

So, in your query,

this.mDb.query(DATABASE_TABLE, new String[] { INFO, SOURCE },INFO + " = '" + info + "'" , null, null, null, null, null);

or

this.mDb.query(DATABASE_TABLE,new String[] {INFO, SOURCE},INFO + " = ?",new String[]
{info},null, null, null, null);