Android系统中自定义按键的短按、双击、长按事件

在项目中碰到这样的问题： 

由于系统中的按键在底层做了重新定义或者新增了按键，此时需要在APP层对按键事件（keyevent）做分解处理，模拟Android系统做法，把keyevent分解成： 

1、单击事件：就是普通key的单击； 

2、双击事件：500ms内同一按键单击两次； 

3、长按事件：同一按键长按超过1000ms（系统中长按事件为500ms）； 

4、组合按键：两个以上按键同时按住； 

其中的keyevent可以来自Activity、View子类的dispatchKeyEvent方法，也可以是我们自定义的接口，也可以是我们发广播送上来的，根据项目需求； 

关于各事件的原理： 

1、双击事件：每次点击的up事件中启动一个定时（500ms）线程消息，用Handler.postDelayed()方法。 

2、长按事件：每次点击的down事件中启动一个定时（1000ms）线程消息，用Handler.postDelayed()方法，注意：在RepeatCount==0时启动； 

3、组合按键：用变量记录每个按键的状态，再进行判断； 

具体代码如下： 

package com.jerome.util;

import android.content.Context;
import android.os.Handler;
import android.util.Log;
import android.view.KeyEvent;

public class KeyUtil {
private boolean isVolumeDown = false;
private boolean isVolumeUp = false;
private boolean isMenu = false;
private int currentKeyCode = 0;

private static Boolean isDoubleClick = false;
private static Boolean isLongClick = false;

CheckForLongPress mPendingCheckForLongPress = null;
CheckForDoublePress mPendingCheckForDoublePress = null;
Handler mHandler = new Handler();

Context mContext = null;
private String TAG = "";

public KeyUtil(Context context, String tag) {
mContext = context;
TAG = tag;
}

public void dispatchKeyEvent(KeyEvent event) {
int keycode = event.getKeyCode();

// 有不同按键按下，取消长按、短按的判断
if (currentKeyCode != keycode) {
removeLongPressCallback();
isDoubleClick = false;
}

// 处理长按、单击、双击按键
if (event.getAction() == KeyEvent.ACTION_DOWN) {
checkForLongClick(event);
} else if (event.getAction() == KeyEvent.ACTION_UP) {
checkForDoubleClick(event);
}

if (keycode == KeyEvent.KEYCODE_VOLUME_DOWN) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
isVolumeDown = true;
} else if (event.getAction() == KeyEvent.ACTION_UP) {
isVolumeDown = false;
}
} else if (keycode == KeyEvent.KEYCODE_VOLUME_UP) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
isVolumeUp = true;
} else if (event.getAction() == KeyEvent.ACTION_UP) {
isVolumeUp = false;
}
} else if (keycode == KeyEvent.KEYCODE_MENU) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
isMenu = true;
} else if (event.getAction() == KeyEvent.ACTION_UP) {
isMenu = true;
}
}

// 判断组合按键
if (isVolumeDown
&& isVolumeUp
&& isMenu
&& (keycode == KeyEvent.KEYCODE_VOLUME_UP
|| keycode == KeyEvent.KEYCODE_VOLUME_DOWN || keycode == KeyEvent.KEYCODE_MENU)
&& event.getAction() == KeyEvent.ACTION_DOWN) {
//组合按键事件处理；
isVolumeDown = false;
isVolumeUp = false;
isMenu = false;
}
}

private void removeLongPressCallback() {
if (mPendingCheckForLongPress != null) {
mHandler.removeCallbacks(mPendingCheckForLongPress);
}
}

private void checkForLongClick(KeyEvent event) {
int count = event.getRepeatCount();
int keycode = event.getKeyCode();
if (count == 0) {
currentKeyCode = keycode;
} else {
return;
}
if (mPendingCheckForLongPress == null) {
mPendingCheckForLongPress = new CheckForLongPress();
}
mPendingCheckForLongPress.setKeycode(event.getKeyCode());
mHandler.postDelayed(mPendingCheckForLongPress, 1000);
}

class CheckForLongPress implements Runnable {

int currentKeycode = 0;

public void run() {
isLongClick = true;
longPress(currentKeycode);
}

public void setKeycode(int keycode) {
currentKeycode = keycode;
}
}

private void longPress(int keycode) {
Log.i(TAG, "--longPress 长按事件--" + keycode);
}

private void singleClick(int keycode) {
Log.i(TAG, "--singleClick 单击事件--" + keycode);
}

private void doublePress(int keycode) {
Log.i(TAG, "---doublePress 双击事件--" + keycode);
}

private void checkForDoubleClick(KeyEvent event) {
// 有长按时间发生，则不处理单击、双击事件
removeLongPressCallback();
if (isLongClick) {
isLongClick = false;
return;
}

if (!isDoubleClick) {
isDoubleClick = true;
if (mPendingCheckForDoublePress == null) {
mPendingCheckForDoublePress = new CheckForDoublePress();
}
mPendingCheckForDoublePress.setKeycode(event.getKeyCode());
mHandler.postDelayed(mPendingCheckForDoublePress, 500);
} else {
// 500ms内两次单击，触发双击
isDoubleClick = false;
doublePress(event.getKeyCode());
}
}

class CheckForDoublePress implements Runnable {

int currentKeycode = 0;

public void run() {
if (isDoubleClick) {
singleClick(currentKeycode);
}
isDoubleClick = false;
}

public void setKeycode(int keycode) {
currentKeycode = keycode;
}
}

private void removeDoublePressCallback() {
if (mPendingCheckForDoublePress != null) {
mHandler.removeCallbacks(mPendingCheckForDoublePress);
}
}
}

注意： 
只有Action Down状态下RepeatCount才会>0，避免长按和单击事件混淆；