Android浅议事件异步处理底层实现原理

本文主要是介绍Android浅议事件异步处理底层实现原理，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

http://www.it165.net/pro/html/201405/13111.html

//主类
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package cn.com.likeshow.bluetoothchat;
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import android.os.Bundle;
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import android.app.Activity;
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import android.view.Menu;
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import android.widget.LinearLayout;
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import android.widget.TextView;
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public class MainActivity extends Activity {
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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final TextView tv=new TextView(getApplicationContext());
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MyButton but=new MyButton(getApplicationContext());
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LinearLayout lin=new LinearLayout(getApplicationContext());
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lin.setOrientation(LinearLayout.VERTICAL);
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lin.addView(tv);
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lin.addView(but);
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setContentView(lin);
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//字定义按钮添加监听器
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//创建你匿名MyListener对象，传给but的setOnClickListener()方法
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but.setOnClickListener(new MyListener() {
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@Override
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public void onClick(MyEvent e) {
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tv.setText("MyEvent事件 "+e.getMessage());
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}
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});
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}
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}

=====================================================================================================

view sourceprint?
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//MyView接口
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package cn.com.likeshow.bluetoothchat;
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public interface MyView {
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//所有控件都用的方法，只能被系统调用
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public void systemEventMetod(MyEvent e);
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}

========================================================================================

view sourceprint?
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//MyListener接口
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package cn.com.likeshow.bluetoothchat;
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import android.view.View;
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public interface MyListener {
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public void onClick(MyEvent e);
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}

===================================================================

view sourceprint?
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//MyEvent简单事件封装类
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package cn.com.likeshow.bluetoothchat;
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public class MyEvent {
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private String eventStr;
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public MyEvent(String eventStr)
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{
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this.eventStr=eventStr;
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}
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public String getMessage()
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{
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return eventStr;
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}
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}

=============================================

view sourceprint?
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//自定义按钮
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package cn.com.likeshow.bluetoothchat;
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import java.util.Date;
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import android.content.Context;
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import android.graphics.Canvas;
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import android.graphics.Color;
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import android.graphics.Paint;
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import android.view.MotionEvent;
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import android.view.View;
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public class MyButton extends View implements MyView {
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private MyListener lis;
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public MyButton(Context context) {
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super(context);
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}
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/**
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*
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* 所用控件都实现的一组规范(即：函数此处假定该函数是public void systemEventMetod(MyEvent e) 系统会调用该函数)
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* 即：当该按钮被点击时，系统自动调用MyView基类中的systemEventMetod(MyEvent e)方法
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*/
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@Override
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public void systemEventMetod(MyEvent e) {
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//防止为调用 setOnClickListener(MyListener lis)时抛空指针异常
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if(lis==null)
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return;
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//通过多态完成调用自己实现的方法
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lis.onClick(e);
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}
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//注册
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public void setOnClickListener(MyListener lis)
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{
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this.lis=lis;
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}
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//绘制按钮界面
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@Override
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public void onDraw(Canvas canvas)
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{
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super.onDraw(canvas);
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Paint p=new Paint();
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p.setColor(Color.GRAY);
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canvas.drawRect(10,80,100,120, p);
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p.setColor(Color.RED);
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canvas.drawText("按钮", 20, 100, p);
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}
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//模拟点击按钮后，系统自动调用MyView基类中的 systemEventMetod(MyEvent e)方法
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//每当创建MyButton时，系统会得到该MyButton对象的引用，当系统获取到屏幕点击时，会自动调用MyButton
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//的 systemEventMetod(MyEvent e)方法
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@Override
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public boolean onTouchEvent(MotionEvent event) {
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String s=new Date().toLocaleString();
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this.systemEventMetod(new MyEvent(s));
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return super.onTouchEvent(event);
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}
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}