通过WifiMange获得ip步骤如下：
WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
int ipAddress = wifiInfo.getIpAddress();
String ip = String.format("%d.%d.%d.%d", (ipAddress & 0xff), (ipAddress >> 8 & 0xff), (ipAddress >> 16 & 0xff), (ipAddress >> 24 & 0xff));
目前还不清楚什么原因，某些设备获取wifiInfo.getIpAddress()返回值是个负数值；
所以查看android源码【AbstractIpAddressPreferenceController.java】
@Override
protected void updateConnectivity() {
String ipAddress = getDefaultIpAddresses(mCM);
if (ipAddress != null) {
mIpAddress.setSummary(ipAddress);
} else {
mIpAddress.setSummary(R.string.status_unavailable);
}
}/**
* Returns the default link's IP addresses, if any, taking into account IPv4 and IPv6style
* addresses.
* @param cm ConnectivityManager
* @return the formatted and newline-separated IP addresses, or null if none.
*/
private static String getDefaultIpAddresses(ConnectivityManager cm) {
LinkProperties prop = cm.getActiveLinkProperties();
return formatIpAddresses(prop);
}private static String formatIpAddresses(LinkProperties prop) {
if (prop == null) return null;
Iterator iter = prop.getAllAddresses().iterator();
// If there are no entries, return null
if (!iter.hasNext()) return null;
// Concatenate all available addresses, newline separated
StringBuilder addresses = new StringBuilder();
while (iter.hasNext()) {
addresses.append(iter.next().getHostAddress());
if (iter.hasNext()) addresses.append("\n");
}
return addresses.toString();
} 可以看到，系统源码是用ConnectivityManager 方法获取，从中提取后方法如下：
ConnectivityManager conMann =(ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mobileNetworkInfo =
conMann.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
NetworkInfo wifiNetworkInfo = conMann.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (mobileNetworkInfo.isConnected()) {
System.out.println("ip ==== " + getLocalIpAddress());
}【android|android WifiMange获取IP为负】经过测试，可以获得正确IP地址；
