android内部培训视频_第四节(1)_异步网络操作

public class downloadImageTask extends AsyncTask<String, Integer, Bitmap> {/** * 在线程开始之前执行 */ @Override protected void onPreExecute() { // TODO Auto-generated method stub super.onPreExecute(); dialog.setTitle("提示"); dialog.setMessage("正在下载数据,请稍候..."); dialog.show(); }/** * 异步执行耗时操作 */ @Override protected Bitmap doInBackground(String... params) {}/** * 执行完成后 */ @Override protected void onPostExecute(Bitmap result) { // TODO Auto-generated method stub super.onPostExecute(result); dialog.dismiss(); image1.setImageBitmap(result); }}

try { HttpResponse response = client.execute(get); if (response.getStatusLine().getStatusCode() == 200) { HttpEntity entity = response.getEntity(); byte[] data = EntityUtils.toByteArray(entity); bitmap = BitmapFactory .decodeByteArray(data, 0, data.length); } // 404/500 } catch (ClientProtocolException e) { // TODO Auto-generated catch block e.printStackTrace(); Toast.makeText(MainActivity.this, "网络请求失败", Toast.LENGTH_LONG) .show(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }

{users: [{face: "001.jpg",headShip: "软件工程师",userName: "周瑜"},{face: "002.jpg",headShip: "开发人员",userName: "陈风"},{face: "003.jpg",headShip: "开发人员",userName: "季炜"},{face: "004.jpg",headShip: "开发人员",userName: "小包"},{face: "005.jpg",headShip: "开发人员",userName: "小裴"}]}

package com.cmcc.utils;public class User { private String userName; private String headShip; private String face; public User() { super(); } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getHeadShip() { return headShip; } public void setHeadShip(String headShip) { this.headShip = headShip; } public String getFace() { return face; } public void setFace(String face) { this.face = face; }}

public class getUserTask extends AsyncTask<String, Void, List<User>>{ @Override protected void onPreExecute() { // TODO Auto-generated method stub super.onPreExecute(); dialog.setTitle("提示"); dialog.setMessage("正在下载,请稍候..."); dialog.show(); } @Override protected List<User> doInBackground(String... params) { // TODO Auto-generated method stub List<User> list = new ArrayList<User>(); HttpClient client = new DefaultHttpClient(); HttpGet get = new HttpGet(params[0]); try { HttpResponse response = client.execute(get); if(response.getStatusLine().getStatusCode() == 200){ String json = EntityUtils.toString(response.getEntity()); JSONObject jsonObj = new JSONObject(json); JSONArray jsonArray = jsonObj.getJSONArray("users"); for(int i = 0;i<jsonArray.length();i++){ JSONObject obj = jsonArray.getJSONObject(i); User user = new User(); user.setUserName(obj.getString("userName")); user.setHeadShip(obj.getString("headShip")); user.setFace(obj.getString("face")); list.add(user); } } } catch (ClientProtocolException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } return list; } @Override protected void onPostExecute(List<User> result) { // TODO Auto-generated method stub super.onPostExecute(result); dialog.dismiss(); myAdapter adapter = new myAdapter(result,MainActivity.this); //自定义adapter，详见下面代码 listview1.setAdapter(adapter); } }

public class myAdapter extends BaseAdapter{ List<User> list; Context context; LayoutInflater inflater; public myAdapter(List<User> list,Context context) { super(); this.list = list; this.context = context; inflater = LayoutInflater.from(context); } @Override public int getCount() { // TODO Auto-generated method stub return list.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return list.get(position); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub View view; if(convertView!=null){ view = convertView; }else{ view = inflater.inflate(R.layout.user, null); } final ImageView face = (ImageView) view.findViewById(R.id.face); TextView tvUserName = (TextView) view.findViewById(R.id.tvUserName); TextView tvHeadShip = (TextView) view.findViewById(R.id.tvHeadShip); tvUserName.setText(list.get(position).getUserName()); tvHeadShip.setText(list.get(position).getHeadShip()); //头像下载，实现类详见后面代码 String imageUrl = "http://xxx.xxxx.xxxx/resources/face/"+list.get(position).getFace(); DownloadFace download = new DownloadFace(imageUrl); download.loadImageFromUrl(new downloadFaceCallBack() { @Override public void setDrawble(Drawable drawable) { // TODO Auto-generated method stub face.setImageDrawable(drawable); } }); return view; } }

package com.cmcc.utils;import java.io.IOException;import java.net.MalformedURLException;import java.net.URL;import android.R.drawable;import android.annotation.SuppressLint;import android.graphics.drawable.Drawable;import android.os.Handler;import android.os.Message;public class DownloadFace { String faceUrl; public DownloadFace(String faceUrl) { super(); this.faceUrl = faceUrl; } @SuppressLint("HandlerLeak") public void loadImageFromUrl(final downloadFaceCallBack callback) { final Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub super.handleMessage(msg); Drawable drawable = (Drawable) msg.obj; callback.setDrawble(drawable); } }; new Thread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub try { Drawable drawable = Drawable.createFromStream(new URL( faceUrl).openStream(), ""); Message msg = Message.obtain(); msg.obj = drawable; handler.sendMessage(msg); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start(); } public interface downloadFaceCallBack { public void setDrawble(Drawable drawable); }}