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);
        }
    };
    
}