一：Android 中Home键监听和Back键监听的区别：
(1).在Android中，当按下Home键的时候，默认情况下Stop前台的Activity，即Activity设置成停止状态【on
Stop()】，而不是销毁状态【onDestory()】。如果再次启动该Activity，不是调用onCreate()方法，而是调用onSavedInstanceState方法。则是从onRestart()开始-on
Start()-onResume()。
(2).当按下back键则不同，back键默认finish前台的activity，即activity的状态为onDestory为止，再次启动该activity则从onCreate开始，不会调用onSavedInstanceState方法。
总而言之：按下Home键会返回桌面，而back则会返回前一个activity。
在这里Back键的实现方法就不赘述了，主要讲解一下Home键的实现方式吧。以下是我找的参考资料自己思考的。请大家给出建议。
Home键监听的实现方法：
(1).在onResum里面注册广播，OnPause里面注销广播。
(2).在广播中拦截Intent.ACTION_CLOSE_SYSTEM_DIALOGS 这个Action ，通过获取Reason字段 来判断长按 还是单击Home键。
代码如下：
(1).Home键监听封装类：
package com.scd.homewatcher.util;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.util.Log; /** * Home键监听封装 * * @author way * */ public class HomeWatcher { // 回调接口 public interface OnHomePressedListener { public void onHomePressed(); public void onHomeLongPressed(); } private static final String TAG = "HomeWatcher"; /** 上下文 */ private Context mContext; /** 过滤器 */ private IntentFilter mFilter; /** 接口 */ private OnHomePressedListener mListener; /** 广播接收者 */ private InnerRecevier mRecevier; public HomeWatcher(Context context) { mContext = context; mRecevier = new InnerRecevier(); mFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS); } /** * 设置监听 * * @param listener */ public void setOnHomePressedListener(OnHomePressedListener listener) { mListener = listener; } /** * 开始监听，注册广播 */ public void startWatch() { if (mRecevier != null) { mContext.registerReceiver(mRecevier, mFilter); } } /** * 停止监听，注销广播 */ public void stopWatch() { if (mRecevier != null) { mContext.unregisterReceiver(mRecevier); } } /** * 广播接收者 */ private class InnerRecevier extends BroadcastReceiver { final String SYSTEM_DIALOG_REASON_KEY = "reason"; final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions"; final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps"; final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey"; @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) { String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY); if (reason != null) { Log.i(TAG, "action:" + action + ",reason:" + reason); if (mListener != null) { if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) { // 短按home键 mListener.onHomePressed(); } else if (reason .equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) { // 长按home键 mListener.onHomeLongPressed(); } } } } } } }
(2).MainActivity类：
package com.scd.homewatcher;import android.app.Activity;import android.os.Bundle;import android.view.KeyEvent;import android.widget.Toast;import com.scd.homewatcher.util.HomeWatcher;import com.scd.homewatcher.util.HomeWatcher.OnHomePressedListener; public class MainActivity extends Activity implements OnHomePressedListener { private HomeWatcher mHomeWatcher; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override protected void onResume() { mHomeWatcher = new HomeWatcher(this); mHomeWatcher.setOnHomePressedListener(this); // 注册广播 mHomeWatcher.startWatch(); super.onResume(); } @Override protected void onPause() { mHomeWatcher.setOnHomePressedListener(null); // 注销广播 mHomeWatcher.stopWatch(); super.onPause(); } @Override public void onHomePressed() { // TODO Toast.makeText(this, "短按Home键,实现自己的逻辑", Toast.LENGTH_SHORT).show(); } @Override public void onHomeLongPressed() { // TODO Toast.makeText(this, "长按Home键,实现自己的逻辑", Toast.LENGTH_SHORT).show(); } @Override public boolean on KeyDown(int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_BACK)) { System.out.println("按下了back键 on KeyDown()"); return false; } else { return super.on KeyDown(keyCode, event); } } @Override public void onBackPressed() { // super.onBackPressed()会自动调用finish()方法,关闭 super.onBackPressed(); } }
