getting error while using viewHolder in a sqlite based application in android

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Mobile

Android

SQLite

hi friends
i tried to design a simple a sqlite related apps .but when i try to inflate my data in listview using view holder.it's getting error.i cannt understand how to debug it. please help me
my code is---
1- code for SQLiteOpenHelper
[code]public class DataHelper extends SQLiteOpenHelper {
public static String DATABASE="kuldb";
public static String DB_TABLE="friends";
public static String COL_id="id";
public static String COL_NAME="name";
public static String COL_ADD="address";
public static String COL_PH="call";

ArrayList<friendmodel>cartlist=new ArrayList<friendmodel>();
Context c;
public DataHelper(Context c){
super(c,DATABASE,null,1);
}
public void onCreate(SQLiteDatabase db){
db.execSQL("create table friends(id integer primary key autoincrement,name text,address text,call text)");
}
public void onUpgrade(SQLiteDatabase db,int oldv,int newv){
db.execSQL("drop table if exist "+DB_TABLE);
this.onCreate(db);
}

public void putfriends(FriendModel fritype){
SQLiteDatabase sd=this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put("name", fritype.friname);
cv.put("address", fritype.friadd);
cv.put("call", fritype.friph);
sd.insert("friends", null, cv);
sd.close();
}

public void updatefri(FriendModel frilist){
SQLiteDatabase sd=this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put("name", frilist.friname);
cv.put("address", frilist.friadd);
cv.put("call", frilist.friph);
sd.update("friends", cv, "name="+ frilist.friname, null);
sd.close();
}
public void emptyfriends(){
try{
SQLiteDatabase sd=this.getWritableDatabase();
sd.execSQL("delete from friends");
sd.close();
}catch(Exception e){
e.printStackTrace();
}
}
public void removefriend(String fname,String fadd,String fph){
try{
SQLiteDatabase sd=this.getWritableDatabase();
String[]arg={fname};
sd.delete("friends", "name=?", arg);
sd.close();
}catch(Exception e){
e.printStackTrace();
}
}

public ArrayList<friendmodel>getallfriends(){
cartlist.clear();
SQLiteDatabase sd=this.getWritableDatabase();
Cursor c=sd.rawQuery("select * from friends", null);
if(c.getCount()!=0){
if(c.moveToFirst()){
do{
FriendModel type=new FriendModel();
type.friname=c.getString(c.getColumnIndex("name"));
type.friadd=c.getString(c.getColumnIndex("address"));
type.friph=c.getString(c.getColumnIndex("call"));
cartlist.add(type);
}while(c.moveToNext());
}
}
c.close();
sd.close();
return cartlist;

}
}
[/code]
2- code for MainActivity
[code]public class MainActivity extends Activity{
EditText fname,fadd,fcall;
Button fsave,fview;
FriendModel fm;
DataHelper help;
public void onCreate(Bundle b){
super.onCreate(b);
setContentView(R.layout.main);
fname=(EditText)findViewById(R.id.addname);
fadd=(EditText)findViewById(R.id.addcity);
fcall=(EditText)findViewById(R.id.addph);
fsave=(Button)findViewById(R.id.savedata);
fview=(Button)findViewById(R.id.viewdata);

fsave.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(fname.getText().toString().equals("")
||fadd.getText().toString().equals("")||fcall.getText().toString().equals("")){
Toast.makeText(MainActivity.this, "please Fill All data fields", Toast.LENGTH_LONG).show();
}
else{
help=new DataHelper(getApplicationContext());
help.getWritableDatabase();
fm=new FriendModel();
fm.friname=fname.getText().toString();
fm.friadd=fadd.getText().toString();
fm.friph=fcall.getText().toString();
help.putfriends(fm);
Toast.makeText(MainActivity.this, "Records Added sucessfully", Toast.LENGTH_LONG).show();
fname.setText("");
fadd.setText("");
fcall.setText("");
}


}
});

fview.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent i=new Intent(getApplicationContext(),ViewFriends.class);
startActivity(i);
}
});
}

}
[/code]
code for FriendModel class
[code]public class FriendModel {
public String friname="";
public String friadd="";
public String friph="";

public String getfriname(){
return friname;
}
public void setfriname(String friname){
this.friname=friname;
}
public String getfriadd(){
return friadd;
}
public void setfriadd(String friadd){
this.friadd=friadd;
}
public String getfriph(){
return friph;
}
public void setfriph(String friph){
this.friph=friph;
}

}

[/code]
code for final ViewFriends classs--
[code]public class ViewFriends extends Activity{
TextView totalfans;
ListView listview;
DataHelper help;
ArrayList<friendmodel>friendlist=new ArrayList<friendmodel>();

public void onCreate(Bundle b){
super.onCreate(b);
setContentView(R.layout.view_record);
totalfans=(TextView)findViewById(R.id.totalrecords);
listview=(ListView)findViewById(R.id.listview);
}
public void onResume(){
super.onResume();
friendlist.clear();
help=new DataHelper(getApplicationContext());
help.getWritableDatabase();
ArrayList<friendmodel>fanlist=help.getallfriends();
for(int i=0;i<fanlist.size();i++){>
String tfname=fanlist.get(i).getfriname();
String tfadd=fanlist.get(i).getfriadd();
String tfph=fanlist.get(i).getfriph();

FriendModel fan=new FriendModel();
fan.setfriname(tfname);
fan.setfriadd(tfadd);
fan.setfriph(tfph);
friendlist.add(fan);
}
totalfans.setText("Total Records Found: "+friendlist.size());
listview.setAdapter(new ListAdapter(this));
help.close();

}
private class ListAdapter extends BaseAdapter{
LayoutInflater inflater;
ViewHolder viewholder;

public ListAdapter(Context c){
inflater=LayoutInflater.from(c);
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return friendlist.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if(convertView==null){
convertView=inflater.inflate(R.layout.item_record, null);
ViewHolder viewholder=new ViewHolder();
viewholder.tfriname=(TextView)convertView.findViewById(R.id.namedb);
viewholder.tfriadd=(TextView)convertView.findViewById(R.id.addressdb);
viewholder.tfriph=(TextView)convertView.findViewById(R.id.calldb);
convertView.setTag(viewholder);
}
else{
viewholder=(ViewHolder)convertView.getTag();
}
viewholder.tfriname.setText(friendlist.get(position).getfriname());
viewholder.tfriadd.setText(friendlist.get(position).getfriadd().trim());
viewholder.tfriph.setText(friendlist.get(position).getfriph().trim());
final int temp=position;

(convertView.findViewById(R.id.update)).setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String updatename=friendlist.get(temp).getfriname();
String updateadd=friendlist.get(temp).getfriadd();
String updateph=friendlist.get(temp).getfriph();
Intent in=new Intent(ViewFriends.this,Update.class);
in.putExtra("fname", updatename);
in.putExtra("fadd", updateadd);
in.putExtra("fph", updateph);
startActivity(in);

}
});
(convertView.findViewById(R.id.delete)).setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AlertDialog.Builder adb=new AlertDialog.Builder(ViewFriends.this);
adb.setCancelable(true);
adb.setMessage("Are you Sure about Delete Record???");
adb.setPositiveButton("Yes", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
help.removefriend(friendlist.get(temp).getfriname().trim()
, friendlist.get(temp).getfriadd().trim(),friendlist.get(temp).getfriph().trim());
ViewFriends.this.onResume();
Toast.makeText(ViewFriends.this, "Record Deleted Sucessfully", Toast.LENGTH_LONG).show();

}
});
adb.setNegativeButton("No", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub

}
});
adb.show();

}
});
return convertView;
}

}
private class ViewHolder{
TextView tfriname;
TextView tfriadd;
TextView tfriph;
}

}
[/code]