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);
		}
	}
}