Android开源框架Volley的使用

一、概述
Volley是google发布的一款android网络通信库，它适合效率要求较高场景以及并发场景。它有如下特点：

• 通信更快、更简单、更健壮。开发效率会得到很大提升，稳定性也会很高。
• GET、POST请求及网络图像的高效率异步处理
• 可以对网络请求进行排序和优先级处理。
• 网络请求的缓存。
• 多级别取消请求。
• 和Activity生命周期的联动。当activity销毁时，可通过
• 不适合网络数据的上传和下载

二、网络数据请求

首先，要自定义一个Application，初始化一个Volley请求队列。并将Application注册到manifest文件中。还要添加网络权限。

public class MyApplication extends Application {    public static RequestQueue queue;    @Override    public void onCreate() {        super.onCreate();        queue = Volley.newRequestQueue(getApplicationContext());    }    public static RequestQueue getHttpQueue() {        return queue;    }}

• StringRequest

//POST请求private void volleyPost() {        String url = "";        StringRequest request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {            @Override            public void onResponse(String s) {                //请求成功的操作            }        }, new Response.ErrorListener() {            @Override            public void onErrorResponse(VolleyError volleyError) {                //请求失败的操作            }        }) {            @Override            protected Map<String, String> getParams() throws AuthFailureError {                Map<String, String> hashMap = new HashMap<String, String>();                hashMap.put("phone", "13838383838");                hashMap.put("key", "sbsbsbsb");                return hashMap;            }        };        request.setTag("abcPost");        MyApplication.getHttpQueues().add(request);

//GET请求private void volleyGet() {       String url = "http://.......?phone=13838383838&key=sbsbsbsbsb";        //1.String        StringRequest request = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {            @Override            public void onResponse(String s) {                Toast.makeText(MainActivity.this, "", Toast.LENGTH_SHORT).show();            }        }, new Response.ErrorListener() {            @Override            public void onErrorResponse(VolleyError volleyError) {                Toast.makeText(MainActivity.this, "请求失败", Toast.LENGTH_SHORT).show();            }        });        request.setTag("abcGet");        MyApplication.getHttpQueues().add(request);

• JsonObjectRequest

//POSTHashMap<String, String> hashMap = new HashMap<String, String>();        hashMap.put("phone", "13838383838");        hashMap.put("key", "sbsbsbsb");        JSONObject object = new JSONObject(hashMap);        JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, url, object, new Response.Listener<JSONObject>() {            @Override            public void onResponse(JSONObject jsonObject) {            }        }, new Response.ErrorListener() {            @Override            public void onErrorResponse(VolleyError volleyError) {            }        });        request.setTag("abcPost");        MyApplication.getHttpQueues().add(request);

//GETJsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {            @Override            public void onResponse(JSONObject jsonObject) {                //请求成功的操作            }        }, new Response.ErrorListener() {            @Override            public void onErrorResponse(VolleyError volleyError) {                // 请求失败的操作            }        });        request.setTag("abcGet");        MyApplication.getHttpQueues().add(request);

• JsonArrayRequest

和JsonObjectRequest大同小异，略。

三、获取网络图片

首先做一下准备工作。。。

<RelativeLayout 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">    <ImageView        android:id="@+id/iv_img"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <com.android.volley.toolbox.NetworkImageView        android:id="@+id/net_iv"        android:layout_width="120dp"        android:layout_height="120dp"        android:layout_centerHorizontal="true"        android:layout_marginTop="30dp"/></RelativeLayout>

//去manifest.xml中注册和添加权限public class MyApplication extends Application {    public static RequestQueue queue;    @Override    public void onCreate() {        super.onCreate();        queue = Volley.newRequestQueue(getApplicationContext());    }    public static RequestQueue getHttpQueue() {        return queue;    }}

iv_img = (ImageView) this.findViewById(R.id.iv_img);networkIv = (NetworkImageView) this.findViewById(R.id.net_iv);String url = "http://www.baidu.com/img/bdlogo.png";

/** * 使用ImageRequest请求网络图片 */mageRequest request = new ImageRequest(url, new Response.Listener<Bitmap>() {       @Override     public void onResponse(Bitmap bitmap) {          iv_img.setImageBitmap(bitmap);     }}, 0, 0, Bitmap.Config.RGB_565, new Response.ErrorListener() {     @Override     public void onErrorResponse(VolleyError volleyError) {         iv_img.setBackgroundResource(R.mipmap.ic_launcher);     }});MyApplication.getHttpQueue().add(request);

/** * 使用ImageLoader缓存网络图片 */ ImageLoader loader = new ImageLoader(MyApplication.getHttpQueue(), new BitmapCache());        ImageLoader.ImageListener listener = ImageLoader.getImageListener(iv_img, R.mipmap.ic_launcher,                R.mipmap.ic_launcher);        loader.get(url, listener);

public class BitmapCache implements ImageLoader.ImageCache {    public LruCache<String, Bitmap> cache;    public int max = 10 * 1024 * 1024; //设置最大缓存大小    public BitmapCache() {        cache = new LruCache<String, Bitmap>(max) {            @Override            protected int sizeOf(String key, Bitmap value) {                return value.getRowBytes() * value.getHeight();            }        };    }    @Override    public Bitmap getBitmap(String s) {        return cache.get(s);    }    @Override    public void putBitmap(String s, Bitmap bitmap) {        cache.put(s, bitmap);    }}

/** * 使用NetworkImageView加载网络图片 */ ImageLoader loader = new ImageLoader(MyApplication.getHttpQueue(), new BitmapCache());        networkIv.setDefaultImageResId(R.mipmap.ic_launcher);        networkIv.setErrorImageResId(R.mipmap.ic_launcher);        networkIv.setImageUrl(url, loader);

NetWorkResponse类

/** * Data and headers returned from {@link Network#performRequest(Request)}. */public class NetworkResponse {    /**     * Creates a new network response.     * @param statusCode the HTTP status code     * @param data Response body     * @param headers Headers returned with this response, or null for none     * @param notModified True if the server returned a 304 and the data was already in cache     * @param networkTimeMs Round-trip network time to receive network response     */    public NetworkResponse(int statusCode, byte[] data, Map<String, String> headers,            boolean notModified, long networkTimeMs) {        this.statusCode = statusCode;        this.data = data;        this.headers = headers;        this.notModified = notModified;        this.networkTimeMs = networkTimeMs;    }    public NetworkResponse(int statusCode, byte[] data, Map<String, String> headers,            boolean notModified) {        this(statusCode, data, headers, notModified, 0);    }    public NetworkResponse(byte[] data) {        this(HttpStatus.SC_OK, data, Collections.<String, String>emptyMap(), false, 0);    }    public NetworkResponse(byte[] data, Map<String, String> headers) {        this(HttpStatus.SC_OK, data, headers, false, 0);    }    /** The HTTP status code. */    public final int statusCode;    /** Raw data from this response. */    public final byte[] data;    /** Response headers. */    public final Map<String, String> headers;    /** True if the server returned a 304 (Not Modified). */    public final boolean notModified;    /** Network roundtrip time in milliseconds. */    public final long networkTimeMs;}