Question

现在我使用hashmap从SQLite中添加值以显示inListview但是当我

时它是错误的

map.put("item_title", friends.getString("nickname"));
map.put("item_fname", friends.getString("fname"));
map.put("item_lname", friends.getString("lname"));

错误告诉我“方法getString在friendEntry中是unfind”

这是我在friendEntry中的代码

package com.example.sqlite.entry;
public class FriendEntry {
private int id;
private String fname;
private String lname;
private String nickname;
public int getId() {
  return id;
}
public void setId(int id) {
  this.id = id;
}
public String getFname() {
  return fname;
}
public void setFname(String fname) {
  this.fname = fname;
}
public String getLname() {
  return lname;
}
public void setLname(String lname) {
  this.lname = lname;
}
public String getNickname() {
  return nickname;
}
public void setNickname(String nickname) {
  this.nickname = nickname;
}

}

FriendsListActivity

package com.example.sqlite;
import java.util.ArrayList;
import java.util.HashMap;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.example.sqlite.db.FriendsDB;
import com.example.sqlite.entry.FriendEntry;
public class FriendsListActivity extends Activity {
private Context context;
private FriendsDB db;
private ArrayList<FriendEntry> friends;
private ArrayList<String> data;
private TextView hellotext;
private ListView hellolistview;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    setContentView(R.layout.friendlist_layout);

}
public void showAllList(){
    //view matching
    hellotext = (TextView) findViewById(R.id.hellotext);
    hellolistview = (ListView) findViewById(R.id.hellolistview);
    //select data
    friends = db.selectAll();
        if(friends.size()==0){
            Toast.makeText(context,"You dont have any friend.",Toast.LENGTH_SHORT).show();
        }else{

            ArrayList<HashMap<String, String>> MyArrList = new ArrayList<HashMap<String, String>>();
            HashMap<String, String> map;
            for (int i = 1;i<=friends.size();i++){
            // set value for data   
                map = new HashMap<String, String>();
                map.put("item_title", friends.getNickname());
                map.put("item_fname", friends.getFname());
                map.put("item_lname", friends.getLname());
                MyArrList.add(map);
            }
            //adapter
            hellolistview.setAdapter(new adapter());
        }
    }

private class adapter extends BaseAdapter{
    private Holder holder;
    @Override

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

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

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        //create
        if( view == null){
            view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item_layout,null);
            holder = new Holder();
            holder.title = (TextView) view.findViewById(R.id.item_title);
            view.setTag(holder);
        }else{
            holder = (Holder) view.getTag();
        }

        //assign data / wait for data 
        holder.title.setText(data.get(position));

        return view;
    }

    private class Holder{
        public TextView title;
    }
}


}

这是我的FriendsDB

 package com.example.sqlite.db;

 import java.util.ArrayList;

 import com.example.sqlite.entry.FriendEntry;

 import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;

 //ใช้ในการ inert update delete
 public class FriendsDB {
 private FriendsDBHelper helper;
 private SQLiteDatabase db;

 public FriendsDB(Context context){
    helper = new FriendsDBHelper(context);
    db = helper.getWritableDatabase();
}
//insert
    public long insert(String fname,String lname,String nickname){
        ContentValues values = new ContentValues();
        values.put(FriendsDBHelper.TABLE_KEY_FNAME, fname);
        values.put(FriendsDBHelper.TABLE_KEY_LNAME, lname);
        values.put(FriendsDBHelper.TABLE_KEY_NICKNAME, nickname);
        return db.insert(FriendsDBHelper.TABLE_NAME, null ,values);

    }
//select all
    public ArrayList<FriendEntry> selectAll(){
        ArrayList<FriendEntry> friends = new ArrayList<FriendEntry>();
        //     cursor คือ ชุดข้อมูล
        Cursor cursor = db.rawQuery("SELECT*FROM"+FriendsDBHelper.TABLE_NAME+"WHERE id != ?",new String[]{Integer.toString(0)});
        cursor.moveToFirst();
        if(cursor.getCount()!=0){
            do{
                FriendEntry friend = new FriendEntry();
                friend.setId(cursor.getInt(cursor.getColumnIndex(FriendsDBHelper.TABLE_KEY_ID)));
                friend.setFname(cursor.getString(cursor.getColumnIndex(FriendsDBHelper.TABLE_KEY_FNAME)));
                friend.setLname(cursor.getString(cursor.getColumnIndex(FriendsDBHelper.TABLE_KEY_LNAME)));
                friend.setNickname(cursor.getString(cursor.getColumnIndex(FriendsDBHelper.TABLE_KEY_NICKNAME)));
                friends.add(friend);

            }while(cursor.moveToNext());

        }

        return friends;
    }

Answer 1

您可以使用：

map.put("item_title", friends.getNickname());

因为您使用Getter setter方法创建了...而且您也可以为其他人创建类似的方法..

Answer 2

您的Friends类不是名为getString(string)

的方法

使用此

map.put("item_title", friends.get(i).getNickname());
map.put("item_fname", friends.get(i).getFname());
map.put("item_lname", friends.get(i).getLname());

要设置昵称，您需要致电friends.setNickname("name")，因为您有以下

    public void setNickname(String nickname) {
    this.nickname = nickname;
    }

编辑：我也看到你有这个showAllList()，但是你没有在活动课的任何地方调用它。在showAllList()之后致电setContentView(R.layout.friendlist_layout)。

在执行db = new FriendsDB(ActivityName.this)之前，您可能需要执行此操作friends = db.selectAll()。

Answer 3

像这样使用

for (int i = 1;i<=friends.size();i++){
            // set value for data   
                map = new HashMap<String, String>();
                map.put("item_title", friends.get(i).getNickname());
                map.put("item_fname", friends.get(i).getFname());
                map.put("item_lname", friends.get(i).getLname());
                MyArrList.add(map);
            }

在arraylist <entry>（hashmap）</entry>中的错误方法getString undefind

3 个答案: