ANDROID_MARS学习笔记_S01原始版_007_Handler及线程的简单使用

一、运行结果

一、代码
1.xml
(1)activity_main.xml

 <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.example.s01_original_e14_simplehandler.MainActivity" >

     <Button
         android:id="@+id/startThread"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/startThread"/>

      <Button
      android:id="@+id/stopThread"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/stopThread"
      android:layout_below="@id/startThread"/>

      <TextView
          android:id="@+id/myTextView"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_below="@id/stopThread"/>

 </RelativeLayout>

2.java
(1)MainActivity.java

 package com.example.s01_original_e14_simplehandler;

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Button;
 import android.widget.TextView;

 public class MainActivity extends Activity {

     private Button startThread = null;
     private Button stopThread = null;
     private TextView myTextView = null;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         myTextView = (TextView) findViewById(R.id.myTextView);
         startThread = (Button) findViewById(R.id.startThread);
         stopThread = (Button) findViewById(R.id.stopThread);

         startThread.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 handler.post(updateThread);
             }
         });

         stopThread.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 handler.removeCallbacks(updateThread);
             }
         });
     }

     Handler handler = new Handler();

     Runnable updateThread = new Runnable() {
         @Override
         public void run() {
             System.out.println("---updateThread");
             myTextView.setText(System.currentTimeMillis()+"");
             handler.postDelayed(updateThread, 2000);
         }
     };

 }