用AsyncTask进行网络取图片

1、新建一个XML，写一个Button,Imgview

<ImageView
        android:id="@+id/imgviews"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <Button 
        android:id="@+id/butns"
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="AsyncTask网络取图"/>

2、新建一个Activty继承Activty，

这里对于控件实例化就不写出来了，直接进入主题

//点击按钮mButton获取网络图片

mButton2.setOnClickListener(new OnClickListener() {
      
      @Override
      public void onClick(View v) {
        getBitmapByAsyncTask("http://www.jimeise.net/wp-content/uploads/2014/05/IMGP6150.jpg");
        
      }
    });
  }
    private void getBitmapByThread(final String httpUrls){
      new Thread() {
        @Override
        public void run() {
          URL url;
          try {
            url = new URL(httpUrls);
            HttpURLConnection connect = (HttpURLConnection) url
                .openConnection();
            InputStream is = connect.getInputStream();
            Bitmap bitmap = BitmapFactory.decodeStream(is);

            Message msg = Message.obtain();
            msg.obj = bitmap;
            mHandler.sendMessage(msg);
          } catch (MalformedURLException e) {
            e.printStackTrace();
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }.start();
    }

      
//用AsyncTask进行网络取图片
  private void getBitmapByAsyncTask(String httpUrl) {
    
    new AsyncTask<String, Void, Bitmap>() {

      @Override
      protected Bitmap doInBackground(String... params) {
        String httpurl = params[0];
        return DownLoadBitmap(httpurl);
      }

      protected void onPostExecute(Bitmap result) {
        if (result != null) {
          ImageView2.setImageBitmap(result);
        } else {
          Toast.makeText(MainActivity.this, "网络取图片出错!",
              Toast.LENGTH_SHORT).show();
        }
      };

    }.execute(httpUrl);
  }
  private Bitmap DownLoadBitmap(String httpUrl) {
    URL url;
    Bitmap bitmap = null;
    HttpURLConnection connect = null;
    InputStream is = null;
    try {
      url = new URL(httpUrl);
      connect = (HttpURLConnection) url.openConnection();
      is = connect.getInputStream();
      bitmap = BitmapFactory.decodeStream(is);
    } catch (MalformedURLException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        if (is != null) {
          is.close();
        }
        if (connect != null) {
          connect.disconnect();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return bitmap;
  }

里面全部是通过封装了的，直接调用。

强调一点就是网络取图片一定要在manifest里注册网络权限：

<uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET"/>