package com.zhuozhuo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Looper;import android.os.Message;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;public class LooperThreadActivity extends Activity{ /** Called when the activity is first created. */  private final int MSG_HELLO = 0; private Handler mHandler;  @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);  new CustomThread().start();//新建并啟動(dòng)CustomThread實(shí)例    findViewById(R.id.send_btn).setOnClickListener(new OnClickListener() {      @Override   public void onClick(View v) {//點(diǎn)擊界面時(shí)發(fā)送消息    String str = "hello";    Log.d("Test", "MainThread is ready to send msg:" + str);    mHandler.obtainMessage(MSG_HELLO, str).sendToTarget();//發(fā)送消息到CustomThread實(shí)例       }  });   }      class CustomThread extends Thread {  @Override  public void run() {   //建立消息循環(huán)的步驟   Looper.prepare();//1、初始化Looper   mHandler = new Handler(){//2、綁定handler到CustomThread實(shí)例的Looper對象    public void handleMessage (Message msg) {//3、定義處理消息的方法     switch(msg.what) {     case MSG_HELLO:      Log.d("Test", "CustomThread receive msg:" + (String) msg.obj);     }    }   };   Looper.loop();//4、啟動(dòng)消息循環(huán)  } }}

public class ThreadHandlerActivity extends Activity { /** Called when the activity is first created. */  private static final int MSG_SUCCESS = 0;//獲取圖片成功的標(biāo)識 private static final int MSG_FAILURE = 1;//獲取圖片失敗的標(biāo)識  private ImageView mImageView; private Button mButton;  private Thread mThread;  private Handler mHandler = new Handler() {  public void handleMessage (Message msg) {//此方法在ui線程運(yùn)行   switch(msg.what) {   case MSG_SUCCESS:    mImageView.setImageBitmap((Bitmap) msg.obj);//imageview顯示從網(wǎng)絡(luò)獲取到的logo    Toast.makeText(getApplication(), getApplication().getString(R.string.get_pic_success), Toast.LENGTH_LONG).show();    break;   case MSG_FAILURE:    Toast.makeText(getApplication(), getApplication().getString(R.string.get_pic_failure), Toast.LENGTH_LONG).show();    break;   }  } };  @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);  mImageView= (ImageView) findViewById(R.id.imageView);//顯示圖片的ImageView  mButton = (Button) findViewById(R.id.button);  mButton.setOnClickListener(new OnClickListener() {      @Override   public void onClick(View v) {    if(mThread == null) {     mThread = new Thread(runnable);     mThread.start();//線程啟動(dòng)    }    else {     Toast.makeText(getApplication(), getApplication().getString(R.string.thread_started), Toast.LENGTH_LONG).show();    }   }  }); }  Runnable runnable = new Runnable() {    @Override  public void run() {//run()在新的線程中運(yùn)行   HttpClient hc = new DefaultHttpClient();   HttpGet hg = new HttpGet("http://csdnimg.cn/www/images/csdnindex_logo.gif");//獲取csdn的logo   final Bitmap bm;   try {    HttpResponse hr = hc.execute(hg);    bm = BitmapFactory.decodeStream(hr.getEntity().getContent());   } catch (Exception e) {    mHandler.obtainMessage(MSG_FAILURE).sendToTarget();//獲取圖片失敗    return;   }   mHandler.obtainMessage(MSG_SUCCESS,bm).sendToTarget();//獲取圖片成功，向ui線程發(fā)送MSG_SUCCESS標(biāo)識和bitmap對象//   mImageView.setImageBitmap(bm); //出錯(cuò)！不能在非ui線程操作ui元素//   mImageView.post(new Runnable() {//另外一種更簡潔的發(fā)送消息給ui線程的方法。//    //    @Override//    public void run() {//run()方法會(huì)在ui線程執(zhí)行//     mImageView.setImageBitmap(bm);//    }//   });  } };