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();
     }
    }
   }
  }
 }

@Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  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);
 }

 @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);
 }