Android SQLite หัด Insert ข้อมูล แต่มัน Insert ไม่ได้อะครับ ทำไงดี

package ken.app.sqldota;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;

/**
 * Created by Dell on 16/10/2556.
 */
public class database extends SQLiteOpenHelper{
    private static final String DB_NAME = "Dota";
    private static final int DB_VERSION = 1;

    public static final String TABLE_NAME = "Product";
    public static final String COL_NAME = "name";

    public database(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }


    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE "+ TABLE_NAME +" (_id INTEGER PRIMARY KEY AUTOINCREMENT, "
                + COL_NAME + " TEXT);");



    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int i, int i2) {
        db.execSQL("DROP TABLE IF EXISTS "+ TABLE_NAME);
        onCreate(db);
    }

    public long insertTest(String name)
    {
        SQLiteDatabase  mDb = this.getWritableDatabase();
    //    mDb.execSQL("INSERT INTO "+TABLE_NAME +" (" +COL_NAME +") VALUES ('"+name+"');");
        ContentValues values=new ContentValues();

        values.put(COL_NAME, name);
        long row= mDb.insert(TABLE_NAME,null, values);
        mDb.close();
        return row;
    }
}

package ken.app.sqldota;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

/**
 * Created by Dell on 16/10/2556.
 */
public class add extends Activity {
    SQLiteDatabase mDb;
    database mHelper;
    Cursor mCursor;
    Button btn;
    EditText edt;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_activity);
        init();



        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if(savedata()){
                    //Toast.makeText(add.this, "Please Enter Name Team ", Toast.LENGTH_SHORT).show();
                    Intent newActivity = new Intent(add.this,MainActivity.class);
                   startActivity(newActivity);
                }

                /*else
                {
                   mDb.execSQL("INSERT INTO "+ database.TABLE_NAME +" (" +database.COL_NAME +") VALUES ('"+name+"');");
                    Toast.makeText(add.this, "Enter Team "+name+" Succeed ", Toast.LENGTH_SHORT).show();
                }*/

            }
        });
     //   mHelper.onUpgrade(mDb, 1, 1);
    }

    private boolean savedata() {
        mHelper = new database(this);
       long in = mHelper.insertTest(edt.getText().toString());
        if(in<=0)
        {
            Toast.makeText(add.this, "Please Enter Name Error Team ", Toast.LENGTH_SHORT).show();
            return  false;
        }
        Toast.makeText(add.this, "Enter Team "+edt.getText().toString()+" Succeed ", Toast.LENGTH_SHORT).show();
        return true;
    }


    private void init()
    {
        btn = (Button) findViewById(R.id.button);
        edt = (EditText) findViewById(R.id.editText);
    }
}