package com.lintao.handledemo;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.widget.TextView;/** * 通过线程修改UI * @author admin * */public class MainActivity extends Activity {    private TextView mTvHandlerDemo;    private Handler myHandler;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mTvHandlerDemo = (TextView)findViewById(R.id.tv_handler_demo);                //实例化一个Handler        myHandler = new MyHandler();        //实例化一个Runnable接口        MyThread m = new MyThread();        //启动该接口        new Thread(m).start();    }    /**     * 接受消息并处理消息 ,此Handler会与当前主线程一块运行，可以用来改变UI等     */    class MyHandler extends Handler {        // 子类必须重写此方法,接受数据        @Override        public void handleMessage(Message msg) {            // TODO Auto-generated method stub            super.handleMessage(msg);            // 此处可以更新UI            Bundle b = msg.getData();            String color = b.getString("text");            MainActivity.this.mTvHandlerDemo.setText(color);        }    }    /**     * 这里就可以用来处理主线程以后的工作，等完成后可以发送信息给主线程     * @author admin     *     */    class MyThread implements Runnable {        public void run() {            //隔了10s            try {                Thread.sleep(10000);            } catch (InterruptedException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            //构造Message            Message msg = new Message();            Bundle b = new Bundle();// 存放数据              b.putString("text", "改变UI");            msg.setData(b);            //发送信息            MainActivity.this.myHandler.sendMessage(msg); // 向Handler发送消息,更新UI        }    }}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.lintao.handledemo.MainActivity$PlaceholderFragment" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world"        android:id="@+id/tv_handler_demo" /></RelativeLayout>