Android – 使用Volley请求网络数据
Android L ； Android Studio 14
个人使用volley的小记，简述使用方法，不涉及volley源码
准备工作
导入Volley.jar包：我使用的是现成的jar包，将其放到app/libs目录下即可
网上可以下载到Volley.jar包
使用volley源代码
从github上pull一个下来git pull https://github.com/mcxiaoke/android-volley.git
把这个文件夹放到工程中，与app目录同级
ImportTest/├── app├── build.gradle├── gradle├── gradle.properties├── gradlew├── gradlew.bat├── ImportTest.iml├── local.properties├── settings.gradle└── volley在android studio中，编辑ImportTest/settings.gradle，加入':volley'
include ':app',':volley'编辑ImportTest/app/build.gradle；在dependencies中加入compile project(':volley')
dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) compile project(':volley')//加进来 testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:23.0.1' compile 'com.android.support:design:23.0.1'}同步一下gradle；可能会错：Gradle sync failed: SSL peer shut down incorrectly
找到这个地方volley/build.gradle，注释掉这两句
//apply from: 'https://raw.github.com/mcxiaoke/gradle-mvn-push/master/jar.gradle'//apply from: 'https://raw.github.com/mcxiaoke/gradle-mvn-push/master/gradle-mvn-push.gradle'使用volley
导入jar包已经完成，接下来需要：
- 申请网络权限
<uses-permission android:name="android.permission.INTERNET"/> - 建立网络请求队列 RequestQueue
- 准备Url
- 请求数据
主要代码在VolleyTest.java中，新建了一个LinearLayout来显示数据
加载String，图片，JSON数据；能够实现异步加载网络图片
VolleyTest.java
/* 用于显示的控件 */ cityName = (TextView) findViewById(R.id.city_name); temper = (TextView) findViewById(R.id.temper); weatherType = (TextView) findViewById(R.id.weather_type); webText = (TextView) findViewById(R.id.web_text); cat = (ImageView) findViewById(R.id.image_cat); wallpaper = (NetworkImageView) findViewById(R.id.image_wallpaper); /* 0.准备url，放到HashMap中备用 */ Map<String, String> sourceUrl = new HashMap<>();/* store url */ sourceUrl.put("beijing", "http://www.weather.com.cn/adat/cityinfo/101010100.html"); sourceUrl.put("cat_earphone", "https://img.zhankr.net/btb0g4uakzq296170.png"); sourceUrl.put("wallpaper0010", "https://img.zhankr.net/1rkjxaim1fc296171.jpg"); /* 1.建立RequestQueue */ RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());/* context */ /* 2.请求JSON文件；这里利用的是天气预报接口 */ JsonObjectRequest jsonRequest = new JsonObjectRequest(sourceUrl.get("beijing"), null, new Response.Listener<JSONObject>() { @Override public void onResponse(JSONObject jsonObject) { Log.d("rust", jsonObject.toString()); /* 2.1处理JSON文件 */ try { JSONObject weather = jsonObject.getJSONObject("weatherinfo"); cityName.setText(weather.getString("city")); StringBuilder temperRange = new StringBuilder(); temperRange.append(weather.getString("temp1")); temperRange.append(" ~ "); temperRange.append(weather.getString("temp2")); temper.setText(temperRange.toString()); weatherType.setText(weather.getString("weather")); } catch (JSONException e) { e.printStackTrace(); cityName.setText("ERROR"); } } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) { Log.e("rust", volleyError.toString()); } }); /* 不要忘记添加到队列中 */ requestQueue.add(jsonRequest);/* add to request queue */ /* 3.请求网络图片 */ ImageRequest catRequest = new ImageRequest(sourceUrl.get("cat_earphone"), new Response.Listener<Bitmap>() { @Override public void onResponse(Bitmap bitmap) { cat.setImageBitmap(bitmap); } }, 0, 0, Bitmap.Config.RGB_565, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) { Log.e("rust", volleyError.toString()); } } ); requestQueue.add(catRequest);/* add to request queue */ /* 3.1异步加载图片 */ ImageLoader imageLoader = new ImageLoader(requestQueue, new BitmapCache()); ImageLoader.ImageListener listener = ImageLoader.getImageListener( wallpaper, R.drawable.orange01, R.drawable.orange02 );/* ImageView，默认显示图片，加载失败后显示的图片*/ imageLoader.get(sourceUrl.get("wallpaper0010"), listener, 400, 400);/* 可指定图片最大尺寸 */ wallpaper.setImageUrl(sourceUrl.get("wallpaper0010"), imageLoader); /* 显示图片 */ /* 4.获取文本，以获取网站文本为例 */ StringRequest stringRequest = new StringRequest( "http://www.cnblogs.com/", new Response.Listener<String>() { @Override public void onResponse(String response) { webText.setText(response); } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError error) { Log.e("TAG", error.getMessage(), error); } }); requestQueue.add(stringRequest);BitmapCache.java
import android.graphics.Bitmap;import android.util.LruCache;import com.android.volley.toolbox.ImageLoader;public class BitmapCache implements ImageLoader.ImageCache { private LruCache<String, Bitmap> mCache; public BitmapCache() { int maxSize = 10 * 1024 * 1024;/* 10M */ mCache = new LruCache<String, Bitmap>(maxSize) { @Override protected int sizeOf(String key, Bitmap bitmap) { return bitmap.getRowBytes() * bitmap.getHeight(); } }; } @Override public Bitmap getBitmap(String url) { return mCache.get(url); } @Override public void putBitmap(String url, Bitmap bitmap) { mCache.put(url, bitmap); }}final
Volley是一个不错的网络框架，源代码可以在frameworks/volley中找到
这里的代码仅仅是实现功能；具体使用中会发现，解析JSON时可能会出现乱码，受网络影响JSON可能加载很慢
