android 接收组播信息
时间: 2023-07-22 11:40:38 浏览: 50
要在 Android 上接收组播信息,您需要执行以下步骤:
1. 获取 MulticastLock 对象以允许接收组播数据包:
```
WifiManager wifi = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
MulticastLock multicastLock = wifi.createMulticastLock("multicastLock");
multicastLock.acquire();
```
2. 创建 MulticastSocket 对象:
```
MulticastSocket multicastSocket = new MulticastSocket(12345); // 12345 是组播端口号
multicastSocket.joinGroup(InetAddress.getByName("239.0.0.1")); // 239.0.0.1 是组播地址
```
3. 接收组播数据包:
```
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
multicastSocket.receive(packet);
String message = new String(packet.getData(), 0, packet.getLength());
```
在接收完组播数据包后,记得释放 MulticastLock 对象:
```
multicastLock.release();
```
注意:您需要在 AndroidManifest.xml 中添加以下权限:
```
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"/>
```