android 键盘事件和屏幕事件的运行原理及交互实现
android 键盘事件和屏幕事件的运行原理及交互实现
发布时间:2016-12-28 来源:查字典编辑
摘要:当在自定义View或者做游戏的时候,我们常常会用到键盘触发事件和屏幕触发事件!在自定义的View里的键盘触发事件(比如:onKeyDown(...

当在自定义View或者做游戏的时候,我们常常会用到键盘触发事件和屏幕触发事件!在自定义的View里的键盘触发事件(比如:onKeyDown(int keyCode, KeyEvent event))和屏幕触发事件(onTouchEvent(MotionEvent event))和activity里的键盘触发事件(比如:onKeyDown(int keyCode, KeyEvent event))和屏幕触发事件(onTouchEvent(MotionEvent event))是怎么样交互的呢?是怎样的一个运行原理呢?下面来看看:

1、屏幕触发事件:哪个activity或者视图,控件在最上层就最先触发这个控件里的屏幕触发事件,返回值如果是默认或者false就会一层一层的往下传递!如果返回值是true,则在执行完动作之后不会往下传递!

2、键盘触发事件:这个原理和屏幕触发事件差不多,但是不同的时,在没有设置控件处于焦点时,一般按键盘里的按键触发的是activity里的键盘触发事件(比如:onKeyDown(int keyCode, KeyEvent event))。

下面来举个例子:

比如在做游戏的时候,我们经常自定义视图,我们一般都喜欢和使用触发本视图(GameView)里的键盘触发事件和屏幕触发事件,但是比如:onKeyDown(int keyCode, KeyEvent event)),一般我们按键盘的时候直接触发的是activity里的键盘触发事件,怎样让它直接触发(GameView)里的键盘触发事件呢?

第一种方法:

例子1:

复制代码 代码如下:

View Code

package net.loonggg.project;

import android.app.Activity;

import android.os.Bundle;

import android.view.KeyEvent;

import android.view.MotionEvent;

public class MainActivity extends Activity {

private GameView gameView;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

gameView = new GameView(this);

setContentView(gameView);

}

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

System.out.println("MainActivity:" + " keyCode:" + keyCode + " evnet:"

+ event);

return super.onKeyDown(keyCode, event);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

System.out.println("MainActivity:" + " event:" + event + " x:"

+ event.getX() + " y:" + event.getY());

return super.onTouchEvent(event);

}

}

package net.loonggg.project;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.view.KeyEvent;

import android.view.MotionEvent;

import android.view.View;

public class GameView extends View {

private Paint paint;

private int pointX;

private int pointY;

public GameView(Context context) {

super(context);

// 设置GameView获得焦点

this.setFocusable(true);

paint = new Paint();

paint.setColor(Color.YELLOW);

Thread t = new Thread(new MyThread());

t.start();

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

canvas.drawCircle(pointX, pointY, 15, paint);

}

class MyThread implements Runnable {

@Override

public void run() {

while (true) {

try {

Thread.sleep(3000);

pointY = pointY + 10;

pointX = pointX + 10;

if (pointX > 200) {

break;

}

} catch (InterruptedException e) {

e.printStackTrace();

}

GameView.this.postInvalidate();

}

}

}

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

System.out.println("GameView:" + " keyCode:" + keyCode + " evnet:"

+ event);

//此事件不会传播出去

return true;

}

@Override

public boolean onTouchEvent(MotionEvent event) {

System.out.println("GameView:" + " event:" + event + " x:"

+ event.getX() + " y:" + event.getY());

//此事件不会传播出去

return true;

}

}

第二种方法:

复制代码 代码如下:

View Code

package net.loonggg.project;

import android.app.Activity;

import android.os.Bundle;

import android.view.KeyEvent;

import android.view.MotionEvent;

public class MainActivity extends Activity {

private GameView gameView;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

gameView = new GameView(this);

setContentView(gameView);

}

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

System.out.println("MainActivity:" + " keyCode:" + keyCode + " evnet:"

+ event);

//把事件传递给gameView

gameView.onKeyDown(keyCode, event);

return super.onKeyDown(keyCode, event);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

System.out.println("MainActivity:" + " event:" + event + " x:"

+ event.getX() + " y:" + event.getY());

//把事件传递给gameView

gameView.onTouchEvent(event);

return super.onTouchEvent(event);

}

}

package net.loonggg.project;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.view.KeyEvent;

import android.view.MotionEvent;

import android.view.View;

public class GameView extends View {

private Paint paint;

private int pointX;

private int pointY;

public GameView(Context context) {

super(context);

paint = new Paint();

paint.setColor(Color.YELLOW);

Thread t = new Thread(new MyThread());

t.start();

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

canvas.drawCircle(pointX, pointY, 15, paint);

}

class MyThread implements Runnable {

@Override

public void run() {

while (true) {

try {

Thread.sleep(3000);

pointY = pointY + 10;

pointX = pointX + 10;

if (pointX > 200) {

break;

}

} catch (InterruptedException e) {

e.printStackTrace();

}

GameView.this.postInvalidate();

}

}

}

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

System.out.println("GameView:" + " keyCode:" + keyCode + " evnet:"

+ event);

return super.onKeyDown(keyCode, event);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

System.out.println("GameView:" + " event:" + event + " x:"

+ event.getX() + " y:" + event.getY());

return super.onTouchEvent(event);

}

}

在这里,推荐使用第二种方法,因为第一种方法有的模拟器不能够使用!

囧神的世界你不懂,虫哥的生活你没有,只有程序猿的世界大家才知道。程序猿们,为了自己的精彩世界奋斗吧,努力吧!加油……

推荐文章
猜你喜欢
附近的人在看
推荐阅读
拓展阅读
相关阅读
网友关注
最新安卓软件开发学习
热门安卓软件开发学习
编程开发子分类