判断wifi是否打开

	public boolean isWifiActive(){
		ConnectivityManager mConnectivity = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
		if(mConnectivity != null){
			NetworkInfo[] infos = mConnectivity.getAllNetworkInfo();
			
			if(infos != null){
				for(NetworkInfo ni: infos){
					if("WIFI".equals(ni.getTypeName()) && ni.isConnected())
						return true;
				}
			}
		}
		
		return false;
	}