如何加载其 URL 存在于在线存储的 JSON 数组中的图像？

Question

我正在尝试将图像加载到列表视图中。图像的 URL 在 JSON 数组中。我能够从该 JSON 数组中获取所有内容，但不能从图像中获取。我是 Android 编程新手。请帮帮我。我已经按照 android hive 的关于 json 解析的教程来涵盖我的代码。

这是从 json 源获取所有数据的类：

package com.plusworks.appdev.youcancook.cuisineFrag;

import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.FrameLayout;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import com.plusworks.appdev.youcancook.base.BaseActivity;
import com.plusworks.appdev.youcancook.base.CheckNetwork;
import com.plusworks.appdev.youcancook.R;
import com.plusworks.appdev.youcancook.base.ServiceHandler;
import com.plusworks.appdev.youcancook.base.SingleDishView;

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

import java.util.ArrayList;
import java.util.HashMap;

public class CuisineDishes extends BaseActivity {

    private ProgressDialog pDialog;

    // URL to get contacts JSON
    private String url;

    // JSON Node names
    private static final String TAG_DISHES = "cuisinedishes";
    private static final String TAG_ID = "id";
    private static final String TAG_NAME = "name";
    private static final String TAG_DESC="shortdesc";
    private static final String TAG_VEG="veg";
    private static final String TAG_DURATION="duration";
    private static final String TAG_SERVINGS="servings";
    private static final String TAG_LEVEL="level";
    private static final String TAG_ICON="icon";

    // contacts JSONArray
    JSONArray dishes = null;

    ArrayList<HashMap<String,String>> dishesList;
    ListView lv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FrameLayout fl = (FrameLayout) findViewById(R.id.main_content);
        LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        final View contentView = inflater.inflate(R.layout.activity_cuisine_dishes, null, false);
        fl.addView(contentView);

        Intent mIntent = getIntent();
        String cuisineName = mIntent.getStringExtra("CuisineName");
        int cuisineId=mIntent.getIntExtra("CuisineId",1);
        getSupportActionBar().setTitle(cuisineName + " Dishes");

        switch (cuisineId){
            case 1:
                url="http://youcancook.site90.com/json/amdishes.json";
                break;
            case 2:
                url="http://youcancook.site90.com/json/britdishes.json";
                break;
            case 3:
                url="http://youcancook.site90.com/json/caribbdishes.json";
                break;
            case 4:
                url="http://youcancook.site90.com/json/chindishes.json";
                break;
            case 5:
                url="http://youcancook.site90.com/json/frenchdishes.json";
                break;
            case 6:
                url="http://youcancook.site90.com/json/greekdishes.json";
                break;
            case 7:
                url="http://youcancook.site90.com/json/inddishes.json";
                break;
            case 8:
                url="http://youcancook.site90.com/json/italiandishes.json";
                break;
            case 9:
                url="http://youcancook.site90.com/json/japanesedishes.json";
                break;
            case 10:
                url="http://youcancook.site90.com/json/meditdishes.json";
                break;
            case 11:
                url="http://youcancook.site90.com//json/mexicandishes.json";
                break;
            case 12:
                url="http://youcancook.site90.com/json/moroccandishes.json";
                break;
            case 13:
                url="http://youcancook.site90.com/json/spanishdishes.json";
                break;
            case 14:
                url="http://youcancook.site90.com/json/thaidishes.json";
                break;
            case 15:
                url="http://youcancook.site90.com/json/turkishdishes.json";
                break;
            case 16:
                url="http://youcancook.site90.com/json/vietdishes.json";
                break;
            default:
                break;
        }

        dishesList=new ArrayList<HashMap<String, String>>();
        lv=(ListView)findViewById(R.id.dish_list);

        //Code to check if internet is working
        if(CheckNetwork.isInternetAvailable(CuisineDishes.this)) //returns true if internet available
        {
            new GetDishes().execute();
        }
        else
        {
            Toast.makeText(CuisineDishes.this,"Bummer! Couldn't connect to our server. Please check your " +
                    "internet connection",Toast.LENGTH_LONG).show();
        }

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent = new Intent(contentView.getContext(), SingleDishView.class);
                intent.putExtra("NAME",dishesList.get(position).get(TAG_NAME));
                intent.putExtra("ID",dishesList.get(position).get(TAG_ID));
                intent.putExtra("NAME",dishesList.get(position).get(TAG_NAME));
                intent.putExtra("VEG",dishesList.get(position).get(TAG_VEG));
                intent.putExtra("DURATION",dishesList.get(position).get(TAG_DURATION));
                intent.putExtra("SERVINGS",dishesList.get(position).get(TAG_SERVINGS));
                intent.putExtra("LEVEL",dishesList.get(position).get(TAG_LEVEL));
                startActivity(intent);
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_cuisine_dishes, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, sop long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        return super.onOptionsItemSelected(item);
    }

    private class GetDishes extends AsyncTask<Void, Void, Void>{
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(CuisineDishes.this);
            pDialog.setMessage("Fetching dishes...");
            pDialog.setCancelable(false);
            pDialog.show();
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            // Creating service handler class instance
            ServiceHandler sh = new ServiceHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    dishes = jsonObj.getJSONArray(TAG_DISHES);

                    // looping through All Contacts
                    for (int i = 0; i < dishes.length(); i++) {
                        JSONObject c = dishes.getJSONObject(i);

                        String id = c.getString(TAG_ID);
                        String name = c.getString(TAG_NAME);
                        String shortdesc = c.getString(TAG_DESC);
                        String veg = c.getString(TAG_VEG);
                        String duration = c.getString(TAG_DURATION);
                        String servings = c.getString(TAG_SERVINGS);
                        String level = c.getString(TAG_LEVEL);
                        String icon=c.getString(TAG_ICON);

                        // tmp hashmap for single contact
                        HashMap<String, String> dishes_temp = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        dishes_temp.put(TAG_ID, id);
                        dishes_temp.put(TAG_NAME, name);
                        dishes_temp.put(TAG_DESC, shortdesc);
                        dishes_temp.put(TAG_VEG, veg);
                        dishes_temp.put(TAG_DURATION, duration);
                        dishes_temp.put(TAG_SERVINGS, servings);
                        dishes_temp.put(TAG_LEVEL, level);
                        dishes_temp.put(TAG_ICON, icon);

                        // adding contact to contact list
                        dishesList.add(dishes_temp);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    CuisineDishes.this, dishesList,
                    R.layout.cuisine_dish_list_item, new String[] { TAG_NAME, TAG_DESC, TAG_ICON}, new int[] { R.id.nameDish,
                    R.id.descDish, R.id.dish_icon});

            lv.setAdapter(adapter);
        }
    }
}

这是单个项目的布局文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/dish_icon"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="5dp" />


    <TextView
        android:id="@+id/nameDish"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toEndOf="@+id/dish_icon"
        android:layout_toRightOf="@+id/dish_icon"
        android:gravity="center_vertical"
        android:text="Line 1"
        android:textColor="#000"
        android:textSize="20sp" />


    <TextView
        android:id="@+id/descDish"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/nameDish"
        android:layout_toRightOf="@+id/dish_icon"
        android:text="Line 2"
        android:textSize="17sp"/>

</RelativeLayout>

Answer 1

protected Bitmap doInBackground(String... args) {
         try {
               bitmap = BitmapFactory.decodeStream((InputStream)new URL(args[0]).getContent());

        } catch (Exception e) {
              e.printStackTrace();
        }
        return bitmap;
     }
     protected void onPostExecute(Bitmap image) {

         if(image != null){
         img.setImageBitmap(image);
         pDialog.dismiss();
}

点击这里>Setting image from url to ImageView with AsynchTask

Answer 2

private String getSplitImages(JSONArray array) {
    StringBuilder result = new StringBuilder();
    try {
        for (int i = 0; i < array.length(); i++) {
            result.append(array.get(i).toString());
            result.append(",");
        }
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return result.length() > 0 ? result.substring(0, result.length() - 1)
            : "";
}