Android线程中设置控件的值提示报错的解决方法

package com.yarin.android.Examples_04_15;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.widget.ImageView;import android.widget.TextView;public class Activity01 extends Activity{ //声明ImageView对象 ImageView imageview; TextView textview; //ImageView的alpha值， int  image_alpha = 255; Handler mHandler = new Handler(); //控件线程 boolean isrung = false; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); isrung = true; //获得ImageView的对象 imageview = (ImageView) this.findViewById(R.id.ImageView01); textview = (TextView) this.findViewById(R.id.TextView01); //设置imageview的图片资源。同样可以再xml布局中像下面这样写 //android:src="@drawable/logo" imageview.setImageResource(R.drawable.logo); //设置imageview的Alpha值 imageview.setAlpha(image_alpha); //开启一个线程来让Alpha值递减 new Thread(new Runnable() {  public void run()  {  while (isrung)  {   try   {   Thread.sleep(200);   //更新Alpha值   updateAlpha();   //如果使用下面注释的代码来直接设置imageview的透明度、textview的值会报错，因为线程中不能对控件进行设置操作，需要使用一个Handler来进行对相关值的设置//   if (image_alpha - 7 >= 0)//   {//    image_alpha -= 7;//   }//   else//   {//    image_alpha = 0;//    isrung = false;//   }//   imageview.setAlpha(image_alpha);//   textview.setText("现在alpha值是："+Integer.toString(image_alpha));   }   catch (InterruptedException e)   {   e.printStackTrace();   }  }  } }).start(); //接受消息之后更新imageview视图 mHandler = new Handler() {  @Override  public void handleMessage(Message msg)  {  super.handleMessage(msg);  imageview.setAlpha(image_alpha);  textview.setText("现在alpha值是："+Integer.toString(image_alpha));  //更新  imageview.invalidate();  } }; } public void updateAlpha() { if (image_alpha - 7 >= 0) {  image_alpha -= 7; } else {  image_alpha = 0;  isrung = false; } //发送需要更新imageview视图的消息 mHandler.sendMessage(mHandler.obtainMessage()); }}