Question

我正在Android Studio上为Android开发社交/消息应用，我想知道如何用JSONArray填充ListView （好友列表）。

My Array（来自Parse currentUser文件：

"friends": ["friend1","friend2","friend3"]

我的活动代码：

package com.mycompany.myapp;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.*;

import com.parse.ParseUser;

import org.json.JSONArray;
import org.json.JSONException;

import java.util.ArrayList;
import java.util.List;


public class friendsTab extends Fragment {

    private ListView friendsLst;
    ParseUser current = ParseUser.getCurrentUser();
    JSONArray friends;



    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v =inflater.inflate(R.layout.friendsview,container,false);

        friendsLst = (ListView)v.findViewById(R.id.friends_list_view);
        friends = current.getJSONArray("friends");



        return v;




    }
}

谢谢！

Answer 1

好的，我会帮你的。

在onCreate（）中的Activity中实例化容器视图和组件。还要创建适配器类的对象，以便可以调用它的构造函数并使用它。

private ListView lvFriends;
private FriendAdapter friendAdapter; // your adapter that will handle the data

@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.friendsview); // <-- this is your container layout name?

   // instantiate your adapter class
   friendAdapter = new FriendAdapter();

   // instantiate your listView
   lvFriends = (ListView) findViewById(R.id.friends_list_view);

   // set up your adapter
   friendAdapter = new FriendAdapter(MainActivity, parseUser); // pass your parseUser object to your adapter (or whatever information you want)
   lvFriends.setAdapter(friendAdapter); // set your adapter  
}

现在在适配器类中执行类似以下的操作

public class FriendAdapter extends BaseAdapter {

   private Context mContext;
   private ParseUser mParseUser;   

   // constructor
   public FriendAdapter(Context context, ParseUser parseUser) {
      this.mContext = context;
      this.mParseUser = parseUser;
   }

   @Override
   public int getCount() {
      // return the size of your friends from your parseUser object 
   }

   @Override
   public long getItemId(int position) {
      return position;
   }

   @Override
   public Object getItem(int position) {
      // return the individual item from your parseUser object
   }


   @Override
   public View getView(int position, View convertView, ViewGroup parent) {
      // you did not post your item view that goes into your container so I will 
      // just assume that it is just a textview

      View view = convertView;
      ViewHolder holder; // use view holder pattern
      if (view == null) {
         LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         view = inflater.inflate(R.layout.item_friend, parent, false);
         holder = new ViewHolder();
         holder.tvFriendName = (TextView) view.findViewById(R.id.tv_friend_name);
         view.setTag(holder);

      } else {
         holder = (ViewHolder) view.getTag();
      }
      return voew;
   }

   private static class ViewHolder {
      private TextView tvFriendName;
   }

}

希望这会有所帮助。干杯！

从Parse.com到Android上的ListView的JSON数组

1 个答案: