Android 监听Home键、Back键、多任务键最新解决方法

前言：在开发中，我们经常会去监听系统的按键操作，最常用的就是监听Back键。有时会用到监听Home和多任务键，但是Android系统默认是不让代码监听的，所以我们就得想别的办法，这里写了通过广播监听日志log的demo。

package com.example.djmsh.client_homekey;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //在setContentView之前添加,未添加的话home键监听无效，设置窗体属性
        this.getWindow().setFlags(0x80000000, 0x80000000);
        setContentView(R.layout.activity_main);

        //创建广播
        InnerRecevier innerReceiver = new InnerRecevier();
        //动态注册广播
        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        //启动广播
        registerReceiver(innerReceiver, intentFilter);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            Toast.makeText(MainActivity.this, "返回键无效", Toast.LENGTH_SHORT).show();
            return true;//return true;拦截事件传递,从而屏蔽back键。
        }
        if (KeyEvent.KEYCODE_HOME == keyCode) {
            Toast.makeText(getApplicationContext(), "HOME 键已被禁用...", Toast.LENGTH_SHORT).show();
            return true;//同理
        }
        return super.onKeyDown(keyCode, event);
    }
    

    class InnerRecevier extends BroadcastReceiver {

        final String SYSTEM_DIALOG_REASON_KEY = "reason";

        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 (Intent.ACTION_CLOSE_SYSTEM_DIALOGS.equals(action)) {
                String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
                if (reason != null) {
                    if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
                        Toast.makeText(MainActivity.this, "Home键被监听", Toast.LENGTH_SHORT).show();
                    } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
                        Toast.makeText(MainActivity.this, "多任务键被监听", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        }
    }
}