android 网络传输图片,Android学习篇章45-HttpClient网络下载-IO流传输-下载图片资源...

Mainactivity:

public class MainActivity extends Activity {

ImageView img1=null;

ProgressDialog dialog=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

img1=(ImageView)findViewById(R.id.img1);

dialog=new ProgressDialog(this);

dialog.setTitle("下载图片");

dialog.setMessage("正在下载请稍候....");

dialog.setCancelable(false);

dialog.setMax(100);

dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

}

public void clickBtn(View view)

{

new MyDownloadImgTask().execute("http://192.168.1.151/advmgr/test.jpg");

}

private class MyDownloadImgTask extends AsyncTask

{

@Override

protected Bitmap doInBackground(String... params) {

// 使用Httpclient发起get请求

String path=params[0];

HttpClient client= new DefaultHttpClient();

//设定get请求

HttpGet get=new HttpGet(path);

try {

//执行这个get请求

HttpResponse response=client.execute(get);

//获得响应的entity

HttpEntity entity=response.getEntity();

//获得传回的图片数据的长度

long size=entity.getContentLength();

Log.i("test", "size="+size);

InputStream is=entity.getContent();

ByteArrayOutputStream bos=new ByteArrayOutputStream();

byte[] buf=new byte[1024];

int length=0;

int sum=0;//用来记录已经读了多少字节的数据

while((length=is.read(buf))>0)

{

//写入到字节输出流中

bos.write(buf, 0, length);

SystemClock.sleep(10);

sum+=length;//记录总的读取的字节数

Log.i("test", "sum="+sum);

int progress=(int)(sum*100.0/size);

Log.i("test", "progress="+progress);

//更新进度

publishProgress(progress);

}

return BitmapFactory.decodeByteArray(bos.toByteArray(), 0, (int)size);

} catch (ClientProtocolException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

@Override

protected void onPostExecute(Bitmap result) {

img1.setImageBitmap(result);

//下载完毕后关闭进度对话框

dialog.dismiss();

super.onPostExecute(result);

}

//在下载任务开始之前显示进度对话框

//当调用了publishProgress方法时就会更新

@Override

protected void onProgressUpdate(Integer... values) {

// TODO Auto-generated method stub

dialog.setProgress(values[0]);

super.onProgressUpdate(values);

}

@Override

protected void onPreExecute() {

dialog.show();

super.onPreExecute();

}

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

}

xml:

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".MainActivity" >

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:onClick="clickBtn"

android:text="图片下载"

/>

android:layout_below="@+id/btn1"

android:scaleType="fitCenter"

android:layout_width="match_parent"

android:layout_height="wrap_content"

/>

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