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", "http://pic.cnblogs.com/avatar/706293/20150628195334.png");
sourceUrl.put("wallpaper0010",
"http://s.cn.bing.net/az/hprichbg/" +
"rb/MaroonBellsVideo_ZH-CN9667920788_1920x1080.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
