Android线程---UI线程和非UI线程之间通信

    近期自学到了线程这一块，用了一上午的时间终于搞出来了主、子线程间的相互通信。当主线程sendMessage后，子线程便会调用handleMessage来获取你所发送的Message。我的主线程向子线程发送消息时携带了数据，子线程根据主线程发送来的数据进行数据库查询，并将查询后的结果返回给该主线程：

  public class UpdataPeople extends Activity {

     EditText updata_name;
     EditText updata_phone;
     EditText updata_address;
     Button updata_quxiao;
     Button updata_baocun;

     String name;
     String phone;

     //创建一个子线程对象
     UpdataThread updataThread ;

     //定义一个全局变量，该Handler在主线程中重写HandleMessage。
     //若不定义成为全局变量，则在子线程中无发用到该Handler
     private Handler mainHandler = null;

     //创建一个非UI线程
     class UpdataThread extends Thread {

         public Handler mhandler;

         public void run() {
             Looper.prepare();
             mhandler = new Handler() {

                 //定义处理消息的方法
                 @Override
                 public void handleMessage(Message msg) {
                     //---这里面做一些耗时操作
                     if (msg.what == 0x123) {
                         //获取msg所携带的数据
                         Bundle bundle = msg.getData();
                         if (bundle != null) {
                             String name = bundle.getString("name");
                             String phone = bundle.getString("phone");
                             Toast.makeText(getApplication(), "传值成功" + name + phone, Toast.LENGTH_LONG).show();
                         } else {
                             name = " ";
                             phone = " ";
                         }
                         //创建并连接数据库，若该数据库已经存在，则打开该数据库
                         CreateDatabaseHelper cdh = new CreateDatabaseHelper(getApplication(), "myPeople.db3", 1);
                         //使用游标查询数据库，并返回结果集
                         Cursor cursor = cdh.getReadableDatabase().rawQuery("select * from people where name = ? and phone = ?", new String[]{name, phone});
                         //创建一个Bundle存储查询出来的结果
                         Bundle dataAll = new Bundle();
                         //遍历cursor，并将结果赋值给Bundle
                         while (cursor.moveToNext()) {
                             dataAll.putString("name", cursor.getString(1));
                             dataAll.putString("phone", cursor.getString(2));
                             dataAll.putString("address", cursor.getString(3));
                         }
     //↓↓↓↓↓↓↓这一块便是子线程将查询的结果返回给主线程↓↓↓↓↓↓↓
                         //创建Message
                         Message msg_main = new Message();
                         msg_main.what = 0x456;
                         //为Message添加数据
                         msg_main.setData(dataAll);
                         //向主线程发送消息
                         mainHandler.sendMessage(msg_main);

                     }
                 }
             };
             Looper.loop();
         }
     }

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         //实例化Thread
         updataThread = new UpdataThread();
         //启动新线程
         updataThread.start();
         setContentView(R.layout.updatapeople);
         //获取布局文件里的控件
         updata_name = (EditText) findViewById(R.id.updata_name);
         updata_phone = (EditText) findViewById(R.id.updata_phone);
         updata_address = (EditText) findViewById(R.id.updata_address);
         updata_quxiao = (Button) findViewById(R.id.updata_quxiao);
         updata_baocun = (Button) findViewById(R.id.updata_baocun);

         //获取启动该Activity的Intent
         Intent intent = getIntent();
         //取出Intent所携带的数据包
         Bundle datas = intent.getExtras();
         //取出包中所携带的各种数据
         if (datas != null) {
             name = datas.getString("name");
             phone = datas.getString("phone");
         } else {
             name = "空";
             phone = "空";
         }
 //↓↓↓↓↓↓↓这一块便是主线程向子线程发送消息↓↓↓↓↓↓↓↓
         //创建消息
         Message msg = new Message();
         //为msg标记一下(类似与--key--)
         msg.what = 0x123;
         //创建一个Bundle,并存放数据
         Bundle bundle = new Bundle();
         bundle.putString("name", name);
         bundle.putString("phone", phone);
         //将数据添加到msg
         msg.setData(bundle);
         //向新线程发送消息
         updataThread.mhandler.sendMessage(msg);

         //接受子线程返回的消息和子线程那边的用法一样
          mainHandler = new Handler() {
             @Override
             public void handleMessage(Message msg_main) {
                 if (msg_main.what == 0x456){
                     //更新UI(因为在UI 线程中可以进行UI的更新。。。)
                     updata_name.setText(msg_main.getData().getString("name"));
                 }
             }
         };