Android获取本地IP地址

首先说明，这个是察看WIFI的IP地址的方法，还需要添加User Permission(android.permission.ACCESS_WIFI_STATE)：

private String getlocalip(){
		WifiManager wifiManager = (WifiManager)getSystemService(Context.WIFI_SERVICE);  
		WifiInfo wifiInfo = wifiManager.getConnectionInfo();  
		int ipAddress = wifiInfo.getIpAddress(); 
		Log.d(Tag, "int ip "+ipAddress);
		if(ipAddress==0)return null;
		return ((ipAddress & 0xff)+"."+(ipAddress>>8 & 0xff)+"."
				+(ipAddress>>16 & 0xff)+"."+(ipAddress>>24 & 0xff));
	}

以下是详细解释这个方法：

在这里，我们可以是察看WifiInfo中的信息即WifiInfo.getIpAddress()，将返回一个int型的IP地址，我们可以看看源代码：

public int getIpAddress() {
        if (mIpAddress == null || mIpAddress instanceof Inet6Address) return 0;
       return NetworkUtils.inetAddressToInt(mIpAddress);
    }

而NetworkUtils.inetAddressToInt(mIpAddress)是

  public static int inetAddressToInt(InetAddress inetAddr)
           throws IllegalArgumentException {
      byte [] addr = inetAddr.getAddress();
      if (addr.length != 4) {
      throw new IllegalArgumentException("Not an IPv4 address");}
      return ((addr[3] & 0xff) << 24) | ((addr[2] & 0xff) << 16) |
            ((addr[1] & 0xff) << 8) | (addr[0] & 0xff);
}

所以，获取到了这个int型的IP地址，我们就还得做一次转换：

return ((ipAddress & 0xff)+"."+(ipAddress>>8 & 0xff)+"."
				+(ipAddress>>16 & 0xff)+"."+(ipAddress>>24 & 0xff));