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：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="fill_parent"
 4     android:layout_height="fill_parent" >
 5 
 6     <ScrollView
 7         android:id="@+id/scrollView1"
 8         android:layout_width="match_parent"
 9         android:layout_height="fill_parent" >
10 
11         <LinearLayout
12             android:layout_width="fill_parent"
13             android:layout_height="fill_parent"
14             android:orientation="vertical"
15             android:weightSum="5" >
16 
17             <TextView
18                 android:id="@+id/textView_for"
19                 android:layout_width="wrap_content"
20                 android:layout_height="wrap_content"
21                 android:layout_gravity="center"
22                 android:layout_weight="3"
23                 android:text="Large Text"
24                 android:textAppearance="?android:attr/textAppearanceLarge" />
25 
26             <EditText
27                 android:id="@+id/editText1_upper"
28                 android:layout_width="wrap_content"
29                 android:layout_height="wrap_content"
30                 android:layout_gravity="center"
31                 android:ems="10"
32                 android:inputType="number" />
33 
34             <Button
35                 android:id="@+id/button_start_thread"
36                 android:layout_width="wrap_content"
37                 android:layout_height="wrap_content"
38                 android:layout_gravity="center"
39                 android:onClick="cal"
40                 android:text="Button" />
41         </LinearLayout>
42     </ScrollView>
43 
44 </RelativeLayout>

逻辑代码如下：

  1 package com.example.mystudy;
  2 
  3 import android.app.Activity;
  4 import android.os.Bundle;
  5 import android.os.Handler;
  6 import android.os.Looper;
  7 import android.os.Message;
  8 import android.view.View;
  9 import android.widget.EditText;
 10 import android.widget.TextView;
 11 
 12 import java.util.ArrayList;
 13 import java.util.List;
 14 
 15 public class MyThreadTest extends Activity {
 16     static final String UPPER_NUM = "upper";
 17     static final String NUMS = "nums";
 18     TextView textView;
 19     EditText editText;
 20     MyThread myThread;
 21 
 22     @Override
 23     protected void onCreate(Bundle savedInstanceState) {
 24 
 25         super.onCreate(savedInstanceState);
 26         setContentView(R.layout.button_and_textview);
 27         editText = (EditText) findViewById(R.id.editText1_upper);
 28         textView = (TextView) findViewById(R.id.textView_for);
 29 
 30         myThread = new MyThread();
 31         myThread.start();// 创建线程
 32 
 33     }
 34 
 35     public void cal(View v) {// 点击事件
 36 
 37         if (editText.getText().toString().equals("")) {
 38             textView.setText("");
 39             return;
 40         }
 41         Message message = new Message();
 42         Bundle bundle = new Bundle();
 43         bundle.putInt(UPPER_NUM, Integer.parseInt(editText.getText().toString()));// 将输入值发给新线程
 44         message.setData(bundle);
 45         message.what = 0x123;
 46         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
 47 
 48     }
 49 
 50     class MyThread extends Thread {
 51         public Handler mHander;// 本线程的hander
 52 
 53         @Override
 54         public void run() {
 55             Looper.prepare();// 创建本线程的looper
 56             mHander = new Handler() { // 实现自己的handler
 57 
 58                 @Override
 59                 public void handleMessage(Message msg) {
 60                     if (msg.what == 0x123) {// 计算质数
 61                         int upper = msg.getData().getInt(UPPER_NUM);
 62                         List<Integer> nums = new ArrayList<Integer>();
 63                         outer:
 64                         for (int i = 2; i <= upper; i++) {
 65                             for (int j = 2; j < Math.sqrt(i); j++) {
 66                                 if (i != 2 && i % j == 0) {
 67                                     continue outer;
 68                                 }
 69                             }
 70                             nums.add(i);
 71                         }
 72 
 73                         Message msg1 = new Message();
 74                         Bundle bundle = new Bundle();
 75                         bundle.putCharSequence(NUMS, nums.toString());
 76                         msg1.setData(bundle);
 77                         msg1.what = 0x124;
 78                         mainHandler.sendMessage(msg1);// 发送给主线程
 79 
 80                     }
 81 
 82                 }
 83 
 84             };
 85             Looper.loop();// 启动looper
 86         }
 87     }
 88 
 89     Handler mainHandler = new Handler() {// UI线程的hander
 90 
 91         @Override
 92         public void handleMessage(Message msg) {
 93             if (msg.what == 0x124) {
 94                 String nums = msg.getData().getCharSequence(NUMS, "no result").toString();
 95                 textView.setText(nums.toString());
 96             }
 97 
 98         }
 99 
100     };
101 
102 }