判斷WiFi是2.4GHZ還是5GHZ

WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
String tempSsidString = wifiInfo.getSSID();
if (tempSsidString != null && tempSsidString.length() > 2) {
    String wifiSsid = tempSsidString.substring(1, tempSsidString.length() - 1);
    List<ScanResult> scanResults=wifiManager.getScanResults();
    for(ScanResult scanResult:scanResults){
	if(scanResult.SSID.equals(wifiSsid)){
	   //傳回4個數字，2開頭的話就是2.4G,5開頭的話就是5G
	   int frequency = scanResult.frequency;
	   break;
	}
    }
}
           

WifiManager wifiManager = (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
		List<ScanResult> scanResults=wifiManager.getScanResults();
		for(ScanResult scanResult:scanResults){
			if(scanResult.SSID.equals(ssid)){//ssid  目前連接配接的wifi
				//傳回4個數字，2開頭的話就是2.4G,5開頭的話就是5G
				int frequency = scanResult.frequency;
				if((frequency+"").startsWith("2")){  //2.4G
					//2.4G TODO
				}else if((frequency+"").startsWith("5")){
					//5G  TODO
				}
			}
		}