Trying to develop a list view in Android with data in database

Hi i am trying to populate a list view with data in the database but i am not able to make it out.Here is the code i tried out

VehicleDisplay Class

package com.android.allianz;

import android.app.Activity;
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.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class VehicleDisplay extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.vehicledisplay);

       SQLiteDatabase db = (new DBAdapter.DatabaseHelper(this)).getWritableDatabase();
        ListView vehList = (ListView)findViewById(R.id.vehcleList);
        Cursor c = db.rawQuery("SELECT P_VEHMD FROM vehicle WHERE P_EMPID = ?", 
                new String[]{"i82112"});
        ListAdapter adap = new SimpleCursorAdapter(
                this, 
                R.layout.vehiclerow, 
                c, 
                new String[] {"P_VEHMD"}, 
                new int[] {R.id.vehMdl});
       /* vehList.setAdapter(adap);*/



        Button bankaccount = (Button) findViewById(R.id.add_vehicle);
        bankaccount.setOnClickListener(new View.OnClickListener(){
            public void onClick(View z){

                Intent bank = new Intent(VehicleDisplay.this,VehicleActivity.class);
                startActivity(bank);
            }
        });

}
}

My Database Class is

DBAdapter Class

package com.android.allianz;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DBAdapter 
{ 

    public static final String V_EMPID = "P_EMPID";
    public static final String V_VEHID = "P_VEHID";
    public static final String V_VEHTP = "P_VEHTP";
    public static final String V_VEHMD = "P_VEHMD";
    public static final String V_REGYR = "P_REGYR";
    public static final String V_REGNO = "P_REGNO";
    public static final String V_INSNM = "P_INSNM";
    public static final String V_INSNO = "P_INSNO";
    public static final String V_INSVY = "P_INSVY";


    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "usersdb";
    private static final String DATABASE_TABLE4 = "vehicle";
    private static final int DATABASE_VERSION = 1;



    private static final String DATABASE_CREATE4 =
        "create table vehicle (P_VEHID integer primary key, "
        + "P_EMPID text, "
        + "P_VEHTP text, "
        + "P_VEHMD text, "
        + "P_REGYR text, "
        + "P_REGNO text, "
        + "P_INSNM text, "
        + "P_INSNO text, "
        + "P_INSVY text );";

    private Context context = null;  
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    public DBAdapter(Context ctx) 
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

    public static class DatabaseHelper extends SQLiteOpenHelper 
    {
        DatabaseHelper(Context context) 
        {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) 
        {

     开发者_如何学C       db.execSQL(DATABASE_CREATE4);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion 
                    + " to "
                    + newVersion + ", which will destroy all old data");

            db.execSQL("DROP TABLE IF EXISTS vehicle");
            onCreate(db);
        }
    }    


    public void open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
    }


    public void close() 
    {
        DBHelper.close();
    }    


    public Boolean AddVehicle(String P_EMPID,String P_VEHTP, String P_VEHMD,
            String P_REGYR, String P_REGNO, String P_INSNM,String P_INSNO, String P_INSVY)
{
Boolean bool = false;
ContentValues initialValues = new ContentValues();
initialValues.put(V_EMPID, P_EMPID);
initialValues.put(V_VEHTP, P_VEHTP);
initialValues.put(V_VEHMD, P_VEHMD);
initialValues.put(V_REGYR, P_REGYR);
initialValues.put(V_REGNO, P_REGNO);
initialValues.put(V_INSNM, P_INSNM);
initialValues.put(V_INSNO, P_INSNO);
initialValues.put(V_INSVY, P_INSVY);

if( db.insert(DATABASE_TABLE4, null, initialValues)> 0)
{
bool = true;
}
else {bool = false;}

return bool;
}


    public boolean Vehicle(String vehtype,String vehModel,String purYear,String regisNo,String insurName,String insurNo,String insurVdty) throws SQLException 
    {
        Cursor mCursor = db.rawQuery("SELECT * FROM " + DATABASE_TABLE4 + " WHERE P_VEHTP=? AND P_VEHMD=? AND P_REGYR=? AND P_REGNO=? AND P_INSNM=? AND P_INSNO=? AND P_INSVY=?", new String[]{vehtype,vehModel,purYear,regisNo,insurName,insurNo,insurVdty});
        if (mCursor != null) {           
            if(mCursor.getCount() > 0)
            {
                return true;
            }
        }
     return false;
    }


}

The XML used are vehicledisplay.xml and vehiclerow.xml

vehicledisplay xml

 <?xml version="1.0" encoding="utf-8"?>


<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/vehicledisp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout android:orientation="vertical"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent">
        <ListView android:layout_width="match_parent"
                  android:id="@+id/vehcleList" android:layout_height="377dp">

        </ListView>
        <Button android:id="@+id/add_vehicle" android:layout_height="wrap_content" android:layout_width="match_parent" android:text="@string/addvehicle"></Button>
    </LinearLayout>
</ScrollView>

vehiclerow xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
    <TextView android:id="@+id/vehMdl" android:layout_width="wrap_content"
        android:layout_height="wrap_content" >
        </TextView>
        </RelativeLayout>

Please kindly help me on this

The problem that stands out to me here is that your table does not have its primary key column named _id. CursorAdapter uses this column internally to maintain consistency.

You should change the name of P_VEHID to _id (I recommend also adding NOT NULL to its specification) or add an _id column and add an index on P_VEHID. Then change your select statement to read:

SELECT _id, P_VEHMD FROM vehicle WHERE P_EMPID = ?