对于Home键的监听不是那么容易,因为Home键可以将程序退出放在后台,所以这个事件是直接分发给系统,系统接收到之后做相应处理,Home键的事件不是直接传递到应用里面.所以在上述监听Back键的代码中,相应的回调中是收不到Home键的事件的.

参考文后的博客链接,对Home键的监听主要通过注册广播接收器实现,拦截让窗口关闭的系统动作,然后根据Intent里面的具体参数,分析当前到底是Home键, 应用切换键,还是其他功能按键.
接收器实现如下：

package com.sinosoft.huataiejia.utils;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

import com.sinosoft.huataiejia.A;
import com.sinosoft.huataiejia.activity.ShowActivity;

/**
 * Author by linkaikai
 * Date on 2019/5/29
 */
public class HomeWatcherReceiver extends BroadcastReceiver {
    private static final String LOG_TAG = "HomeReceiver";

    private static final String SYSTEM_DIALOG_REASON_KEY = "reason";
    //action内的某些reason
    private static final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";//home键旁边的最近程序列表键
    private static final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";//按下home键
    private static final String SYSTEM_DIALOG_REASON_LOCK = "lock";//锁屏键
    private static final String SYSTEM_DIALOG_REASON_ASSIST = "assist";//某些三星手机的程序列表键

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
//        App app = (App) context.getApplicationContext();
        Log.i(LOG_TAG, "onReceive: action: " + action);
        if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {//Action
            // android.intent.action.CLOSE_SYSTEM_DIALOGS
            String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
            LogUtils.i(LOG_TAG, "reason: " + reason);

            if (SYSTEM_DIALOG_REASON_HOME_KEY.equals(reason)) { // 短按Home键
                //可以在这里实现关闭程序操作。。。
                LogUtils.i(LOG_TAG, "homekey");
         
            } else if (SYSTEM_DIALOG_REASON_RECENT_APPS.equals(reason)) {//Home键旁边的显示最近的程序的按钮
                // 长按Home键 或者 activity切换键
                LogUtils.i(LOG_TAG, "long press home key or activity switch");
            } else if (SYSTEM_DIALOG_REASON_LOCK.equals(reason)) {  // 锁屏，似乎是没有反应，监听Intent.ACTION_SCREEN_OFF这个Action才有用
                LogUtils.i(LOG_TAG, "lock");
            } else if (SYSTEM_DIALOG_REASON_ASSIST.equals(reason)) {   // samsung 长按Home键
                LogUtils.i(LOG_TAG, "assist");
            }

        }
    }

}

Home键监听的动态注册 (Android 8.0的手机采取静态注册收不到onReceive的回调)

private static HomeWatcherReceiver mHomeKeyReceiver = null;

    private static void registerHomeKeyReceiver(Context context) {
        Log.i(LOG_TAG, "registerHomeKeyReceiver");
        mHomeKeyReceiver = new HomeWatcherReceiver();
        final IntentFilter homeFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);

        context.registerReceiver(mHomeKeyReceiver, homeFilter);
    }

    private static void unregisterHomeKeyReceiver(Context context) {
        Log.i(LOG_TAG, "unregisterHomeKeyReceiver");
        if (null != mHomeKeyReceiver) {
            context.unregisterReceiver(mHomeKeyReceiver);
        }
    }

在Activity 的onResume和onPause里面分别调用

@Override
    protected void onResume() {
        super.onResume();

        registerHomeKeyReceiver(this);
    }

    @Override
    protected void onPause() {

        unregisterHomeKeyReceiver(this);
        super.onPause();
    }