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文章图片

MainActivity如下:
【android开发网络优化|android开发网络优化 Volley异步加载数据(JSON和图片)完整示例】
package cc.testvolley; import org.json.JSONObject; import android.app.Activity; import android.app.ProgressDialog; import android.graphics.Bitmap; import android.os.Bundle; import android.support.v4.util.LruCache; import android.widget.ImageView; import com.android.volley.Request; import com.android.volley.RequestQueue; import com.android.volley.Response; import com.android.volley.VolleyError; import com.android.volley.toolbox.ImageLoader; import com.android.volley.toolbox.ImageLoader.ImageCache; import com.android.volley.toolbox.ImageLoader.ImageListener; import com.android.volley.toolbox.JsonObjectRequest; import com.android.volley.toolbox.NetworkImageView; import com.android.volley.toolbox.Volley; /** * Demo描述: * 1 利用Volley获取JSON数据 * 2 利用Volley异步加载图片 * 1 利用NetworkImageView加载网路图片 * * 参考资料: * 1 http://blog.csdn.net/t12x3456/article/details/9221611 * 2 http://blog.csdn.net/xyz_lmn/article/details/12063561 * 3 http://blog.csdn.net/lfdfhl/article/details/12221875 *Thank you very much */public class MainActivity extends Activity { private ImageView mImageView; private NetworkImageView mNetworkImageView; @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); init(); } private void init(){ mImageView=(ImageView) findViewById(R.id.imageView); mNetworkImageView=(NetworkImageView)findViewById(R.id.networkImageView); getJSONByVolley(); loadImageByVolley(); showImageByNetworkImageView(); } /** * 利用Volley获取JSON数据 */ private void getJSONByVolley() { RequestQueue requestQueue = Volley.newRequestQueue( this ); String JSONDataUrl = "http://pipes.yahooapis.com/pipes/pipe.run?_id=giWz8Vc33BG6rQEQo_NLYQ&_render=json" ; final ProgressDialog progressDialog = ProgressDialog.show( this , "This is title" , "...Loading..." ); JsonObjectRequest jsonObjectRequest = new JsonObjectRequest( Request.Method.GET, JSONDataUrl, null , new Response.Listener() { @Override public void onResponse(JSONObject response) { System.out.println( "response=" +response); if (progressDialog.isShowing()&&progressDialog!= null ) { progressDialog.dismiss(); } } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError arg0) { System.out.println( "sorry,Error" ); } }); requestQueue.add(jsonObjectRequest); } /** * 利用Volley异步加载图片 * * 注意方法参数: * getImageListener(ImageView view, int defaultImageResId, int errorImageResId) * 第一个参数:显示图片的ImageView * 第二个参数:默认显示的图片资源 * 第三个参数:加载错误时显示的图片资源 */ private void loadImageByVolley(){ String imageUrl= "http://avatar.csdn.net/6/6/D/1_lfdfhl.jpg" ; RequestQueue requestQueue = Volley.newRequestQueue( this ); final LruCache lruCache = new LruCache( 20 ); ImageCache imageCache = new ImageCache() { @Override public void putBitmap(String key, Bitmap value) { lruCache.put(key, value); } @Override public Bitmap getBitmap(String key) { return lruCache.get(key); } }; ImageLoader imageLoader = new ImageLoader(requestQueue, imageCache); ImageListener listener = ImageLoader.getImageListener(mImageView, R.drawable.ic_launcher,R.drawable.ic_launcher); imageLoader.get(imageUrl, listener); } /** * 利用NetworkImageView显示网络图片 */ private void showImageByNetworkImageView(){ String imageUrl= "http://avatar.csdn.net/6/6/D/1_lfdfhl.jpg" ; RequestQueue requestQueue = Volley.newRequestQueue( this ); final LruCache lruCache = new LruCache( 20 ); ImageCache imageCache = new ImageCache() { @Override public void putBitmap(String key, Bitmap value) { lruCache.put(key, value); } @Override public Bitmap getBitmap(String key) { return lruCache.get(key); } }; ImageLoader imageLoader = new ImageLoader(requestQueue, imageCache); mNetworkImageView.setTag( "url" ); mNetworkImageView.setImageUrl(imageUrl,imageLoader); } } main.xml如下:


< 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" > < com.android.volley.toolbox.NetworkImageView android:id = "@+id/networkImageView" android:layout_width = "120dip" android:layout_height = "120dip" android:layout_centerHorizontal = "true" android:layout_marginTop = "30dip" /> < ImageView android:id = "@+id/imageView" android:layout_width = "120dip" android:layout_height = "120dip" android:layout_centerInParent = "true" /> RelativeLayout >



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