为什么我的GridView显示不出数据库内容——新手求教

package com.hzc;import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.GridView;
import android.widget.SimpleAdapter;import com.hzc.newstyc.DataBaseHelper;
import com.hzc.newstyc.R;import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;import static com.hzc.newstyc.R.mipmap.a;public class UsersActivity extends AppCompatActivity {    private  GridView gridView;
    private List<Map<String,Object>>dataList;
    private int[] pic;
    String name1;
    private SimpleAdapter simpleAdapter;
    int Price1;
    int Sheng1;    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.content_users);
        gridView=(GridView)findViewById(R.id.grid);
        dataList=new ArrayList<Map<String, Object>>();
        getdata();
        simpleAdapter=new SimpleAdapter(this,getdata(),R.layout.content_my_grid,new String[]{"PIC","NAME","SURPlUS","PRICE"},new int[]{R.id.griditem_pic,R.id.griditem_name,R.id.griditem_Surplus,R.id.griditem_Price});
        gridView.setAdapter(simpleAdapter);
    }
    private List<Map<String,Object>> getdata(){
        DataBaseHelper dataBaseHelper=new DataBaseHelper(this,"tb_text",1);
        SQLiteDatabase db=dataBaseHelper.getReadableDatabase();
        Cursor c=db.rawQuery("select * from tb_text",null);
        if(c!=null){
        c.moveToFirst();        do {
        Map<String,Object>map=new HashMap<String,Object>();
            byte[] b = c.getBlob(c.getColumnIndex("image"));            Bitmap bmpout = BitmapFactory.decodeByteArray(b, 0, b.length);            map.put("PIC", bmpout);
            name1 = c.getString(c.getColumnIndex("name"));
            map.put("NAME",name1);
            Sheng1 = c.getInt(c.getColumnIndex("Surplus"));
            map.put("SURPlUS",Sheng1);
            Price1 = c.getInt(c.getColumnIndex("Price"));
            map.put("PRICE",Price1);            dataList.add(map);
        }while (c.moveToNext());
        c.close();
        }
        db.close();
        return dataList;    }    }