未发现android设备,Android – jmdns没有发现设备
我是Android的ZeroConf Browser的作者,我使用开源库JmDNS进行所有解析.它工作得很好,但有一些技巧可以让它正常工作.
>在Android manifest.xml中,确保至少拥有这些权限.
>在开始活动之前,您必须通过获取多播锁来允许多播数据包.
@Override
protected void onStart() {
Log.i(TAG, "Starting ServiceActivity...");
super.onStart();
try {
Log.i(TAG, "Starting Mutlicast Lock...");
WifiManager wifi = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
// get the device ip address
final InetAddress deviceIpAddress = getDeviceIpAddress(wifi);
multicastLock = wifi.createMulticastLock(getClass().getName());
multicastLock.setReferenceCounted(true);
multicastLock.acquire();
Log.i(TAG, "Starting ZeroConf probe....");
jmdns = JmDNS.create(deviceIpAddress, HOSTNAME);
jmdns.addServiceTypeListener(this);
} catch (IOException ex) {
Log.e(TAG, ex.getMessage(), ex);
}
Log.i(TAG, "Started ZeroConf probe....");
}
private InetAddress getDeviceIpAddress(WifiManager wifi) {
InetAddress result = null;
try {
// default to Android localhost
result = InetAddress.getByName("10.0.0.2");
// figure out our wifi address, otherwise bail
WifiInfo wifiinfo = wifi.getConnectionInfo();
int intaddr = wifiinfo.getIpAddress();
byte[] byteaddr = new byte[] { (byte) (intaddr & 0xff), (byte) (intaddr >> 8 & 0xff),
(byte) (intaddr >> 16 & 0xff), (byte) (intaddr >> 24 & 0xff) };
result = InetAddress.getByAddress(byteaddr);
} catch (UnknownHostException ex) {
Log.w(TAG, String.format("getDeviceIpAddress Error: %s", ex.getMessage()));
}
return result;
}
>不要忘记停止扫描以解锁多播锁并关闭JmDNS.
@Override
protected void onStop() {
Log.i(TAG, "Stopping ServiceActivity...");
super.onStop();
stopScan();
}
private static void stopScan() {
try {
if (jmdns != null) {
Log.i(TAG, "Stopping ZeroConf probe....");
jmdns.unregisterAllServices();
jmdns.close();
jmdns = null;
}
if (multicastLock != null) {
Log.i(TAG, "Releasing Mutlicast Lock...");
multicastLock.release();
multicastLock = null;
}
} catch (Exception ex) {
Log.e(TAG, ex.getMessage(), ex);
}
}
>最重要的是不要使用默认构造函数.您必须使用IP地址构造函数.我注意到你的代码中只是在做JmDNS.create().我认为由于某种原因,它在Android上运行的唯一方法是使用下面的构造函数.
jmdns = JmDNS.create(deviceIpAddress, HOSTNAME);