Android使用HttpClient下载图片，,HttpURLConne

Android使用HttpClient下载图片，,HttpURLConne

HttpURLConnection与HttpClient的区别：HttpClient是个很不错的开源框架（org.appache.http），封装了访问http的请求头，参数，内容体，响应等等，使用起来更方面更强大。HttpURLConnection是java的标准类，可以实现简单的基于URL请求、响应功能，什么都没封装，用起来太原始，比如重访问的自定义，以及一些高级功能等。

还是在上一章的基础上添加HttpClient

/**     * 通过Get获取网页内容     *      * @param url     *            如：http://preview.quanjing.com/is002/ev601-025.jpg     * @return     * @throws ClientProtocolException     * @throws IOException     * @date 2014.05.10     */    public static Bitmap getHttpGetBitmap(String url)            throws ClientProtocolException, IOException {        Bitmap bitmap = null;        // 新建一个默认的连接        HttpClient client = new DefaultHttpClient();        // 新建一个Get方法        HttpGet get = new HttpGet(url);        // 得到网络的回应        HttpResponse response = client.execute(get);        // 如果服务器响应的是OK的话！        if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {            InputStream is = response.getEntity().getContent();            bitmap = BitmapFactory.decodeStream(is);            is.close();        }        return bitmap;    }

访问互联网权限

<uses-permission android:name="android.permission.INTERNET" />

Activity下载代码

package com.dzt.downloadimage;import java.io.IOException;import java.net.MalformedURLException;import org.apache.http.client.ClientProtocolException;import android.app.Activity;import android.graphics.Bitmap;import android.os.AsyncTask;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ImageView;import com.dzt.downloadimage.utils.HttpUtils;public class MainActivity extends Activity implements OnClickListener {    private Bitmap mDownloadImage = null;    private ImageView image = null;    private downloadImageTask task;    private boolean _isExe = false;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initWidgets();        task = new downloadImageTask();    }    @Override    protected void onStop() {        // TODO Auto-generated method stub        super.onStop();        if (_isExe) {            task.cancel(true); // 取消操作        }    }    private void initWidgets() {        image = (ImageView) findViewById(R.id.img);        Button btn = (Button) findViewById(R.id.download_btn);        btn.setOnClickListener(this);    }    @Override    public void onClick(View v) {        // TODO Auto-generated method stub        switch (v.getId()) {        case R.id.download_btn:            if (!_isExe) {                task.execute("http://preview.quanjing.com/is002/ev601-025.jpg"); // 执行异步操作                _isExe = true;            }            break;        default:            break;        }    }    class downloadImageTask extends AsyncTask<String, Integer, Boolean> {        @Override        protected Boolean doInBackground(String... params) {            // TODO Auto-generated method stub            System.out.println("[downloadImageTask->]doInBackground "                    + params[0]);            // try {            // mDownloadImage = HttpUtils.getNetWorkBitmap(params[0]);            // } catch (MalformedURLException e) {            // // TODO Auto-generated catch block            // e.printStackTrace();            // } catch (IOException e) {            // // TODO Auto-generated catch block            // e.printStackTrace();            // }            try {                mDownloadImage = HttpUtils.getHttpGetBitmap(params[0]);            } catch (ClientProtocolException e) {                // TODO Auto-generated catch block                e.printStackTrace();            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            return true;        }        // 下载完成回调        @Override        protected void onPostExecute(Boolean result) {            // TODO Auto-generated method stub            image.setImageBitmap(mDownloadImage);            System.out.println("result = " + result);            super.onPostExecute(result);        }        // 更新进度回调        @Override        protected void onProgressUpdate(Integer... values) {            // TODO Auto-generated method stub            super.onProgressUpdate(values);        }    }}