Android http 下载图片

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本文主要是介绍Android http下载图片操作，具体先看代码。

1.MainActivity.java

public class MainActivity extends Activity implements OnClickListener {private String TAG="MainActivity";private Bitmap mDownloadImage = null;private ImageView image = null;private downloadImageTask task;private boolean _isExe = false;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initWidgets();task = new downloadImageTask();}@Overrideprotected void onStop() {// TODO Auto-generated method stubsuper.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);}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubswitch (v.getId()) {case R.id.download_btn:if (!_isExe) {Toast.makeText(getApplicationContext(), "正在下载请稍后...", Toast.LENGTH_SHORT).show();task.execute("http://f.hiphotos.baidu.com/image/w%3D2048/sign=3b06d28fc91349547e1eef6462769358/d000baa1cd11728b22c9e62ccafcc3cec2fd2cd3.jpg"); // 执行异步操作_isExe = true;}break;default:break;}}class downloadImageTask extends AsyncTask<String, Integer, Boolean> {@Overrideprotected Boolean doInBackground(String... params) {// TODO Auto-generated method stubLog.d(TAG,"[downloadImageTask->]doInBackground "+ params[0]);mDownloadImage = HttpUtils.getNetWorkBitmap(params[0]);return true;}// 下载完成回调@Overrideprotected void onPostExecute(Boolean result) {// TODO Auto-generated method stubimage.setImageBitmap(mDownloadImage);Log.d(TAG,"result = " + result);super.onPostExecute(result);}// 更新进度回调@Overrideprotected void onProgressUpdate(Integer... values) {// TODO Auto-generated method stubsuper.onProgressUpdate(values);}}}

2.HttpUtils.java

/** * http工具类 http可以使用HttpURLConnection或HttpClient *  */public class HttpUtils {private static String TAG="HttpUtils";/** * 获取网络图片 *  * @param urlString *            如：http://f.hiphotos.baidu.com/image/w%3D2048/sign=3 *            b06d28fc91349547e1eef6462769358 *            /d000baa1cd11728b22c9e62ccafcc3cec2fd2cd3.jpg * @return */public static Bitmap getNetWorkBitmap(String urlString) {URL imgUrl = null;Bitmap bitmap = null;try {imgUrl = new URL(urlString);// 使用HttpURLConnection打开连接HttpURLConnection urlConn = (HttpURLConnection) imgUrl.openConnection();urlConn.setDoInput(true);urlConn.connect();// 将得到的数据转化成InputStreamInputStream is = urlConn.getInputStream();// 将InputStream转换成Bitmapbitmap = BitmapFactory.decodeStream(is);is.close();} catch (MalformedURLException e) {// TODO Auto-generated catch blockLog.d(TAG,"[getNetWorkBitmap->]MalformedURLException");e.printStackTrace();} catch (IOException e) {Log.d(TAG,"[getNetWorkBitmap->]IOException");e.printStackTrace();}return bitmap;}}

3.布局文件activity_main.xml

<LinearLayout 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"    android:orientation="vertical"   >   <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textStyle="bold"        android:textSize="24dip"        android:layout_gravity="center"        android:text="http下载图片测试 "/>    <Button android:id="@+id/download_btn"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="下载"/>    <ImageView        android:id="@+id/img"        android:layout_width="wrap_content"        android:layout_height="wrap_content"      /></LinearLayout>

4.修改配置文件AndroidManifest.xml,添加相应权限

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

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