Android异步下载网络图片 （三个全）

package com.zook; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import android.app.Activity; import android.app.ProgressDialog; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.FrameLayout; import android.widget.ImageView; import android.widget.ProgressBar; public class main extends Activity implements OnClickListener{ private static final String params="http://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Hukou_Waterfall.jpg/800px-Hukou_Waterfall.jpg"; private Button btnFirst,btnSecond,btnThree; private ProgressBar progress; private FrameLayout frameLayout; private Bitmap bitmap=null; ProgressDialog dialog=null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); btnFirst=(Button)this.findViewById(R.id.btnFirst); btnSecond=(Button)this.findViewById(R.id.btnSecond); btnThree=(Button)this.findViewById(R.id.btnThree); progress=(ProgressBar)this.findViewById(R.id.progress); progress.setVisibility(View.GONE); frameLayout=(FrameLayout)this.findViewById(R.id.frameLayout); btnFirst.setOnClickListener(this); btnSecond.setOnClickListener(this); btnThree.setOnClickListener(this); } //前台ui线程在显示ProgressDialog， //后台线程在下载数据，数据下载完毕，关闭进度框 @Override public void onClick(View view) { switch(view.getId()){ case R.id.btnFirst: System.out.println("open"); dialog = ProgressDialog.show(this, "", "下载数据，请稍等 …", true, true); //启动一个后台线程 handler.post(new Runnable(){ @Override public void run() { //这里下载数据 try{ URL url = new URL(params); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setDoInput(true); conn.connect(); InputStream inputStream=conn.getInputStream(); bitmap = BitmapFactory.decodeStream(inputStream); Message msg=new Message(); msg.what=1; System.out.println("11111111111111"); handler.sendMessage(msg); } catch (MalformedURLException e1) { e1.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }); break; case R.id.btnSecond: MyASyncTask yncTask=new MyASyncTask(this,frameLayout); yncTask.execute(params); break; case R.id.btnThree: System.out.println("start"); progress.setVisibility(View.VISIBLE); final Handler newhandler=new Handler(); ExecutorService executorService=Executors.newFixedThreadPool(1); // executorService.execute(command) executorService.execute(new Runnable(){ @Override public void run() { try { URL newurl = new URL(params); HttpURLConnection conn = (HttpURLConnection)newurl.openConnection(); conn.setDoInput(true); conn.connect(); InputStream inputStream=conn.getInputStream(); bitmap = BitmapFactory.decodeStream(inputStream); newhandler.post(new Runnable(){ @Override public void run() { ImageView view=(ImageView)frameLayout.findViewById(R.id.image); view.setImageBitmap(bitmap); } }); } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }); progress.setVisibility(View.GONE); break; } } /**这里重写handleMessage方法，接受到子线程数据后更新UI**/ private Handler handler=new Handler(){ @Override public void handleMessage(Message msg){ switch(msg.what){ case 1: //关闭 ImageView view=(ImageView)frameLayout.findViewById(R.id.image); view.setImageBitmap(bitmap); System.out.println("close"); dialog.dismiss(); break; } } }; }