AsyncTask的使用 （二）图片下载，进度条
16lz
2021-01-26
import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import org.apache.http.HttpResponse;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import android.os.AsyncTask;import android.os.Bundle;import android.app.Activity;import android.app.ProgressDialog;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.ImageView;public class MainActivity extends Activity { private ProgressDialog dialog; private Button button; private ImageView p_w_picpathView; private String p_w_picpath_path = "http://i1.juyouqu.com/uploads/content//2014/04/1396611698344.jpg!w598"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); dialog = new ProgressDialog(this); dialog.setTitle("提示"); dialog.setMessage("正在下载......."); dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);// dialog.show(); button = (Button)findViewById(R.id.button1); p_w_picpathView = (ImageView)findViewById(R.id.p_w_picpathView1); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub new MyTask().execute(p_w_picpath_path); } }); } public class MyTask extends AsyncTask { @Override protected void onPreExecute() { // TODO Auto-generated method stub super.onPreExecute(); dialog.show(); } @Override protected Bitmap doInBackground(String... params) { // TODO Auto-generated method stub Bitmap bitmap = null; ByteArrayOutputStream output = new ByteArrayOutputStream(); InputStream input = null; try { HttpClient httpClient = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(params[0]); HttpResponse httpResponse = httpClient.execute(httpGet); if (httpResponse.getStatusLine().getStatusCode() == 200) { input = httpResponse.getEntity().getContent(); long file_length = httpResponse.getEntity().getContentLength(); int len = 0; byte[] data = new byte[1024]; int total_length = 0; int value = 0; while((len = input.read(data)) != -1) { total_length += len; value = (int)((total_length / (float)file_length) * 100); publishProgress(value); output.write(data, 0, len); } byte[] result = output.toByteArray(); bitmap = BitmapFactory.decodeByteArray(result, 0, result.length); } } catch (Exception e) { // TODO: handle exception }finally { if(input != null) try { input.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(output != null) try { output.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return bitmap; } @Override protected void onPostExecute(Bitmap result) { // TODO Auto-generated method stub super.onPostExecute(result); dialog.dismiss(); p_w_picpathView.setImageBitmap(result); } @Override protected void onProgressUpdate(Integer... values) { // TODO Auto-generated method stub super.onProgressUpdate(values); dialog.setProgress(values[0]); } }} 更多相关文章
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