Android 網絡請求框架Volley實例詳解
首先上效果圖

Logcat日志信息on Reponse

Volley特別適合數據量不大但是通信頻繁的場景,像文件上傳下載不適合!
首先第一步
用到的RequetQueue
RequestQueue.Java
RequestQueue請求隊列首先得先說一下,ReuqestQueue是如何對請求進行管理的...RequestQueue是對所有的請求進行保存...然后通過自身的start()方法開啟一個CacheDispatcher線程用于緩存調度,開啟若干個NetWorkDispatcher線程用于網絡調度...那么為什么要這樣設計呢?
因為一個請求如果已經提交了一次,那么就只需要處理這一次結果就可以了,對于多次重復的請求,我們完全可以使用一個緩存來進行保存..從而減少一些不必要的網絡請求,減小服務器的負擔...如果一個請求在緩存中沒存在過,那么我們再執行網絡請求就可以了
總而言之,設計理念就是從RequestQueue取出請求,先判斷緩存是否命中,如果緩存命中,則從緩存中取出數據,如果緩存沒有命中,則提交網絡請求,從服務器端獲取數據
導入volley.jar 到您的Project libs里面,然后Add to Build path
然后創建NetCacheActivity類
package com.Android.xiong.gridlayoutTest;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.Toast;import com.android.volley.Request.Method;import com.android.volley.RequestQueue;import com.android.volley.Response;import com.android.volley.VolleyError;import com.android.volley.toolbox.ImageRequest;import com.android.volley.toolbox.StringRequest;import com.android.volley.toolbox.Volley;public class NetCacheActivity extends Activity {private static final String URL = "http://sina.com";//請求的urlprivate RequestQueue mRequestQueue;private Button btn_request;private ImageView iv_request;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.main);initView(); mRequestQueue = Volley.newRequestQueue(getApplicationContext()); }private void initView() {// TODO Auto-generated method stubbtn_request = (Button) findViewById(R.id.btn_request);iv_request=(ImageView) findViewById(R.id.iv_request);}public void onClick(View v) {//volleyRequest();從網絡上獲取圖片imageRequest();LoadImageView();//ImageLoader加載圖片}private void imageRequest() {// TODO Auto-generated method stub ImageRequest mImageRequest=new ImageRequest("http://www.bz55.com/uploads/allimg/130716/1-130G6111637.jpg", new Response.Listener<Bitmap>() { //需要的注意的是導入Response.Listener<Bitmap>別導錯包!@Overridepublic void onResponse(Bitmap response) {// 將網絡請求的圖片返回并顯示在ImageView中 try {Thread.sleep(3000);//休眠3秒 iv_request.setImageBitmap(response);Toast.makeText(getApplicationContext(), " onResponse", Toast.LENGTH_SHORT).show();Log.d(" onResponse", response.toString());} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}}},0, 0, Config.RGB_565, new Response.ErrorListener() {@Overridepublic void onErrorResponse(VolleyError error) {// 默認加載圖片資源iv_request.setImageResource(R.drawable.ic_launcher);Toast.makeText(getApplicationContext(), " onErrorResponse", Toast.LENGTH_SHORT).show();Log.d(" onErrorResponse", error.toString());}}); mRequestQueue.add(mImageRequest);//強圖片請求添加到請求隊列}public void LoadImageView() {// 利用ImageLoader異步加載圖片final ImageLoader mImageLoader = new ImageLoader(mquest,new BitmapCache());ImageListener listener = ImageLoader.getImageListener(iv_request,R.drawable.voice_to_short, R.drawable.ic_launcher); //get請求方式mImageLoader.get("http://img.my.csdn.NET/uploads/201404/13/1397393290_5765.jpeg",listener);Log.d("ImageLoader", mImageLoader.toString());}// import com.android.volley.Response.ErrorListener;private void volleyRequest() {StringRequest mRequest = new StringRequest(Method.GET, URL,new Response.Listener<String>() {@Overridepublic void onResponse(String response) {// TODO Auto-generated method stubToast.makeText(getApplicationContext(), "onResponse ",Toast.LENGTH_LONG).show();Log.d("on onResponse", response.toString());//請求成功}}, new Response.ErrorListener() {@Overridepublic void onErrorResponse(VolleyError error) {// TODO Auto-generated method stubToast.makeText(getApplicationContext(),"onErrorResponse", Toast.LENGTH_SHORT).show();Log.d("on ErrorReponse", error.toString());//請求失敗}}); mRequestQueue.add(mRequest); }}BitmapCache
package com.weixin.cache;import android.graphics.Bitmap;import android.support.v4.util.LruCache;import com.android.volley.toolbox.ImageLoader.ImageCache;public class BitmapCache implements ImageCache { private LruCache<String, Bitmap> cache; public BitmapCache() { cache = new LruCache<String, Bitmap>(8 * 1024 * 1024) { @Override protected int sizeOf(String key, Bitmap bitmap) { return bitmap.getRowBytes() * bitmap.getHeight(); } }; } @Override public Bitmap getBitmap(String url) { return cache.get(url); } @Override public void putBitmap(String url, Bitmap bitmap) { cache.put(url, bitmap); } } 布局文件activity_main.xml
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/RelativeLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <ImageView android:id="@+id/iv_request" android:layout_width="wrap_content" android:layout_height="wrap_content" android:scaleType="fitXY" android:src="@drawable/bitmap" /> <Button android:id="@+id/btn_request" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:onClick="onClick" android:text="獲取網絡請求信息" /></RelativeLayout>
感謝閱讀,希望能幫助到大家,謝謝大家對本站的支持!
新聞熱點
疑難解答