Question

我无法弄清楚如何使用适配器（myadapter）将凌空响应传递给listview。我是否使用myadapter.add（）并将其传递给它？我阅读了教程，经过几周的尝试，我认为是时候寻求帮助了。所以如果你有时间，我很感激你能不能帮助我。谢谢。我能够在textview中显示回复。

  package hfad.com.adapters;


    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Log;
    import android.widget.ArrayAdapter;
    import android.widget.ListView;
    import android.widget.TextView;

    import com.android.volley.RequestQueue;
    import com.android.volley.Response;
    import com.android.volley.VolleyError;
    import com.android.volley.toolbox.JsonArrayRequest;
    import com.android.volley.toolbox.Volley;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    public class MainActivity extends Activity {

        //thorntech.com parsing jsonandroid using colley library
        TextView results;
        // URL of object to be parsed
        String JsonURL = "https://raw.githubusercontent.com/ianbar20/JSON-Volley-Tutorial/master/Example-JSON-Files/Example-Array.JSON";
        // This string will hold the results
        String data = "";
        // Defining the Volley request queue that handles the URL request concurrently

        ListView myList;

        RequestQueue requestQueue;

        //Adding adapter and assign it -set- to a listview



        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            // Creates the Volley request queue
            requestQueue = Volley.newRequestQueue(this);

            // Casts results into the TextView found within the main layout XML with id jsonData
            results = (TextView) findViewById(R.id.textView);
            myList = (ListView) findViewById(R.id.listv);
            final ArrayAdapter<String> myAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1);
            ListView myList = (ListView) findViewById(R.id.listv);
            myList.setAdapter(myAdapter);

            // Creating the JsonArrayRequest class called arrayreq, passing the required parameters
            //JsonURL is the URL to be fetched from
            JsonArrayRequest arrayreq = new JsonArrayRequest(JsonURL,
                    // The second parameter Listener overrides the method onResponse() and passes
                    //JSONArray as a parameter
                    new Response.Listener<JSONArray>() {

                        // Takes the response from the JSON request
                        @Override
                        public void onResponse(JSONArray response) {


                     //Juan suggestion:
                     ArrayList<String> myArraylist
                    myArraylist = new ArrayList<String>();

            }}

我的mainactivity.xml：包括textview和listview。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp"
    tools:context=".MainActivity"
    android:weightSum="1">


    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

   <ListView
       android:id="@+id/listv"
       android:layout_width="match_parent"
       android:layout_height="89dp"/>


</LinearLayout>

我的问题是如何使用arrayadapter将响应从volley传递到listview？

Answer 1

在这里：

 public void onResponse(JSONArray response) {

 }

您应该浏览JSONArray并提取每个字符串并放入ArrayList<String>。

ArrayList<String> stringsFromJson = new ArrayList<>();

然后，在同一个地方，您将值设置为适配器：

myAdapter.clear();
myAdapter.addAll(stringsFromJson); 
myAdapter.notifyDataSetChanged();

此外，您的适配器应定义为ArrayAdapter<String>。

编辑1

您需要考虑的一些事项：

您必须为清单添加INTERNET权限
在您粘贴的代码中，您实际上并未将请求发送到服务器。为此，您需要将您的请求添加到请求队列。
您提取的JSON不仅仅是字符串列表，因此根据您要显示的内容，您可能需要更改listview的布局，适配器和/或填充后面的arraylist的方式适配器。

为了举例，我选择了使用形状名称填充listview的简单替代方法。您可以尝试和更改其他替代方案。

清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.apackagename.so_43691098">

    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">

        <activity android:name="SO_43691098">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

主要活动

package com.apackagename.so_43691098;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonRequest;
import com.android.volley.toolbox.Volley;

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

import java.util.ArrayList;


public class SO_43691098 extends AppCompatActivity {

        private static final String TAG = SO_43691098.class.getSimpleName();

        //thorntech.com parsing jsonandroid using colley library
        TextView results;
        // URL of object to be parsed
        String JsonURL = "https://raw.githubusercontent.com/ianbar20/JSON-Volley-Tutorial/master/Example-JSON-Files/Example-Array.JSON";
        // This string will hold the results
        String data = "";
        // Defining the Volley request queue that handles the URL request concurrently

        ListView myList;

        RequestQueue requestQueue;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main_activity);
            // Creates the Volley request queue
            requestQueue = Volley.newRequestQueue(this);

            // Casts results into the TextView found within the main layout XML with id jsonData
            results = (TextView) findViewById(R.id.textView);
            myList = (ListView) findViewById(R.id.listv);
            final ArrayAdapter<String> myAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1);
            ListView myList = (ListView) findViewById(R.id.listv);
            myList.setAdapter(myAdapter);

            // Creating the JsonArrayRequest class called arrayreq, passing the required parameters
            //JsonURL is the URL to be fetched from
            JsonArrayRequest arrayRequest = new JsonArrayRequest(JsonURL,
                    new Response.Listener<JSONArray>(){

                        @Override
                        public void onResponse(JSONArray response) {
                            //Juan suggestion:
                            ArrayList<String> myArrayList = new ArrayList<>();

                            try {
                                JSONArray shapes = response.getJSONObject(1).getJSONArray("shapeArray");
                                for(int i=0; i<shapes.length(); i++) {
                                    myArrayList.add(shapes.getJSONObject(i).getString("shapeName"));
                                }
                            } catch (JSONException e){
                                    Log.e(TAG, "Getting shape name", e);
                            }

                            myAdapter.clear();
                            myAdapter.addAll(myArrayList);
                            myAdapter.notifyDataSetChanged();
                        }
                    },
                    new Response.ErrorListener(){

                        @Override
                        public void onErrorResponse(VolleyError error) {
                            Log.e(TAG, error.getMessage(), error);
                        }
                    }
            );

            requestQueue.add(arrayRequest);

        }
}

我没有对布局进行任何更改。

使用ArrayAdapter将凌空响应传递给listview

1 个答案: