Android/BroadcastReceiver如何判断Wifi P2P是否开启？

public class WifiP2PBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) {
            int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1);
            if (state == WifiP2pManager.WIFI_P2P_STATE_ENABLED) {
                // Wifi P2P已开启
                // 在这里进行相应的操作
            } else {
                // Wifi P2P未开启
                // 在这里进行相应的操作
            }
        }
    }
}

WifiP2pManager wifiP2pManager;
WifiP2pManager.Channel channel;
WifiP2PBroadcastReceiver receiver;

// 初始化WifiP2pManager和WifiP2pManager.Channel
wifiP2pManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
channel = wifiP2pManager.initialize(this, getMainLooper(), null);

// 创建BroadcastReceiver实例
receiver = new WifiP2PBroadcastReceiver();

// 注册BroadcastReceiver并监听Wifi P2P状态变化的广播消息
IntentFilter filter = new IntentFilter();
filter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
registerReceiver(receiver, filter);

unregisterReceiver(receiver);