新建线程与UI线程间的通信

现在用一个实例来演示一下自己的新建线程与UI线程间的通信。

UI界面包含3个控件：

一个输入框，用来输入数字；

一个显示框，用来显示从2开始，到输入数字之间的所有质数；

一个按钮,点击后获取输入框输入的数字，交给新建线程处理，线程计算质数后把结果传给UI线程，UI线程显示结果到显示框。

XML如下：

 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent" >

     <ScrollView
         android:id="@+id/scrollView1"
         android:layout_width="match_parent"
         android:layout_height="fill_parent" >

         <LinearLayout
             android:layout_width="fill_parent"
             android:layout_height="fill_parent"
             android:orientation="vertical"
             android:weightSum="5" >

             <TextView
                 android:id="@+id/textView_for"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="center"
                 android:layout_weight="3"
                 android:text="Large Text"
                 android:textAppearance="?android:attr/textAppearanceLarge" />

             <EditText
                 android:id="@+id/editText1_upper"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="center"
                 android:ems="10"
                 android:inputType="number" />

             <Button
                 android:id="@+id/button_start_thread"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="center"
                 android:onClick="cal"
                 android:text="Button" />
         </LinearLayout>
     </ScrollView>

 </RelativeLayout>

逻辑代码如下：

 package com.example.mystudy;

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.view.View;
 import android.widget.EditText;
 import android.widget.TextView;

 import java.util.ArrayList;
 import java.util.List;

 public class MyThreadTest extends Activity {
     static final String UPPER_NUM = "upper";
     static final String NUMS = "nums";
     TextView textView;
     EditText editText;
     MyThread myThread;

     @Override
     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);
         setContentView(R.layout.button_and_textview);
         editText = (EditText) findViewById(R.id.editText1_upper);
         textView = (TextView) findViewById(R.id.textView_for);

         myThread = new MyThread();
         myThread.start();// 创建线程

     }

     public void cal(View v) {// 点击事件

         if (editText.getText().toString().equals("")) {
             textView.setText("");
             return;
         }
         Message message = new Message();
         Bundle bundle = new Bundle();
         bundle.putInt(UPPER_NUM, Integer.parseInt(editText.getText().toString()));// 将输入值发给新线程
         message.setData(bundle);
         message.what = 0x123;
         myThread.mHander.sendMessage(message);// 调用自己的线程中的hander来发送message,将消息放进线程的消息队列中等待hander处理

     }

     class MyThread extends Thread {
         public Handler mHander;// 本线程的hander

         @Override
         public void run() {
             Looper.prepare();// 创建本线程的looper
             mHander = new Handler() { // 实现自己的handler

                 @Override
                 public void handleMessage(Message msg) {
                     if (msg.what == 0x123) {// 计算质数
                         int upper = msg.getData().getInt(UPPER_NUM);
                         List<Integer> nums = new ArrayList<Integer>();
                         outer:
                         for (int i = 2; i <= upper; i++) {
                             for (int j = 2; j < Math.sqrt(i); j++) {
                                 if (i != 2 && i % j == 0) {
                                     continue outer;
                                 }
                             }
                             nums.add(i);
                         }

                         Message msg1 = new Message();
                         Bundle bundle = new Bundle();
                         bundle.putCharSequence(NUMS, nums.toString());
                         msg1.setData(bundle);
                         msg1.what = 0x124;
                         mainHandler.sendMessage(msg1);// 发送给主线程

                     }

                 }

             };
             Looper.loop();// 启动looper
         }
     }

     Handler mainHandler = new Handler() {// UI线程的hander

         @Override
         public void handleMessage(Message msg) {
             if (msg.what == 0x124) {
                 String nums = msg.getData().getCharSequence(NUMS, "no result").toString();
                 textView.setText(nums.toString());
             }

         }

     };

 }