android开发网络优化 Volley异步加载数据(JSON和图片)完整示例

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MainActivity如下:

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 >

转载于:https://my.oschina.net/sharesuiyue/blog/405369