當(dāng)在自定義View或者做游戲的時(shí)候，我們常常會(huì)用到鍵盤(pán)觸發(fā)事件和屏幕觸發(fā)事件！在自定義的View里的鍵盤(pán)觸發(fā)事件（比如：onKeyDown(int keyCode, KeyEvent event)）和屏幕觸發(fā)事件（onTouchEvent(MotionEvent event)）和activity里的鍵盤(pán)觸發(fā)事件（比如：onKeyDown(int keyCode, KeyEvent event)）和屏幕觸發(fā)事件（onTouchEvent(MotionEvent event)）是怎么樣交互的呢？是怎樣的一個(gè)運(yùn)行原理呢？下面來(lái)看看：
1、屏幕觸發(fā)事件：哪個(gè)activity或者視圖，控件在最上層就最先觸發(fā)這個(gè)控件里的屏幕觸發(fā)事件，返回值如果是默認(rèn)或者false就會(huì)一層一層的往下傳遞！如果返回值是true,則在執(zhí)行完動(dòng)作之后不會(huì)往下傳遞！
2、鍵盤(pán)觸發(fā)事件：這個(gè)原理和屏幕觸發(fā)事件差不多，但是不同的時(shí)，在沒(méi)有設(shè)置控件處于焦點(diǎn)時(shí)，一般按鍵盤(pán)里的按鍵觸發(fā)的是activity里的鍵盤(pán)觸發(fā)事件（比如：onKeyDown(int keyCode, KeyEvent event)）。
下面來(lái)舉個(gè)例子：
比如在做游戲的時(shí)候，我們經(jīng)常自定義視圖，我們一般都喜歡和使用觸發(fā)本視圖（GameView）里的鍵盤(pán)觸發(fā)事件和屏幕觸發(fā)事件，但是比如：onKeyDown(int keyCode, KeyEvent event）)，一般我們按鍵盤(pán)的時(shí)候直接觸發(fā)的是activity里的鍵盤(pán)觸發(fā)事件，怎樣讓它直接觸發(fā)（GameView）里的鍵盤(pán)觸發(fā)事件呢?
第一種方法：
例子1：
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);
// 設(shè)置GameView獲得焦點(diǎn)
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);
//此事件不會(huì)傳播出去
return true;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
System.out.println("GameView:" + " event:" + event + " x:"
+ event.getX() + " y:" + event.getY());
//此事件不會(huì)傳播出去
return true;
}
}
第二種方法：
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);
//把事件傳遞給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());
//把事件傳遞給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);
}
}
在這里，推薦使用第二種方法，因?yàn)榈谝环N方法有的模擬器不能夠使用！
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