在Xamarin.iOS中检查蓝牙状态（打开/关闭）

Question

我正在寻找一种能够获取设备蓝牙状态的功能，因此我可以告诉应用程序用户蓝牙的打开或关闭。

当前代码一直在说蓝牙即使打开也已关闭。任何帮助和指导表示赞赏！

public bool CheckBluetoothStatus()
        {
            bool status;

            if (state == CBCentralManagerState.PoweredOn)
            {
                status = true;
                bluetoothEnabledLbl.Text = "Bluetooth enabled";
                bluetoothEnabledAdviceLbl.Text = "Consider turning Bluetooth off if not in use or check to see if all connected devices are recognisable";

                return status;
            }
            else
            {
                status = false;
                bluetoothEnabledLbl.Text = "Bluetooth not enabled";

                return status;
            }
        }

Answer 1

尝试此操作，如果没有任何更改，可能是由于设备版本：

private CBCentralManagerState state; 
public bool CheckBluetoothStatus()
    {
        bool status;

        if (state == CBCentralManagerState.PoweredOn)
        {
            status = true;
            bluetoothEnabledLbl.Text = "Bluetooth enabled";
            bluetoothEnabledAdviceLbl.Text = "Consider turning Bluetooth off if not in use or check to see if all connected devices are recognisable";

        }
        else
        {
            status = false;
            bluetoothEnabledLbl.Text = "Bluetooth not enabled";

        }
            return status;
    }

Answer 2

开发两个[[Xamarin iOS蓝牙应用程序时需要注意两个要点。

• First

，您需要在物理设备中运行它，无法在模拟器设备中测试蓝牙功能。如果那样，您将始终获得带有共享代码的控制台日志：

2020-02-28 13：32：38.310442 + 0800 AppIOSBluetooth [36757：5394891]蓝牙未启用

• 第二

，您需要在info.plist文件中添加蓝牙应用程序的权限。首次运行应用程序时，将显示权限弹出窗口。

但是，在info.plist中，您可以按照以下步骤轻松添加Bluetooth的权限，而会忘记另一个最重要的权限：

<key>NSBluetoothPeripheralUsageDescription</key>
<string>Add BlueTooth Peripheral Permission</string>

对于蓝牙来说，这还不够。您还需要添加另一个权限：
<key>NSBluetoothAlwaysUsageDescription</key>
<string>use Bluetooth</string>

此外，有关在Xamarin iOS中使用蓝牙的an offical API doc，您可以看看。
public override void ViewDidLoad ()
{
    base.ViewDidLoad ();
    // Perform any additional setup after loading the view, typically from a nib.
    myDel = new MySimpleCBCentralManagerDelegate();
    var myMgr = new CBCentralManager(myDel, DispatchQueue.CurrentQueue);
}

public class MySimpleCBCentralManagerDelegate : CBCentralManagerDelegate
{
    override public void UpdatedState(CBCentralManager mgr)
    {
        if (mgr.State == CBCentralManagerState.PoweredOn)
        {
            Console.WriteLine("Consider turning Bluetooth off if not in use or check to see if all connected devices are recognisable");
            //Passing in null scans for all peripherals. Peripherals can be targeted by using CBUIIDs
            CBUUID[] cbuuids = null;
            mgr.ScanForPeripherals(cbuuids); //Initiates async calls of DiscoveredPeripheral
                                                //Timeout after 30 seconds
            var timer = new Timer(30 * 1000);
            timer.Elapsed += (sender, e) => mgr.StopScan();
        }
        else
        {
            //Invalid state -- Bluetooth powered down, unavailable, etc.
            System.Console.WriteLine("Bluetooth is not available");
        }
    }
    public override void DiscoveredPeripheral(CBCentralManager central, CBPeripheral peripheral, NSDictionary advertisementData, NSNumber RSSI)
    {
        Console.WriteLine("Discovered {0}, data {1}, RSSI {2}", peripheral.Name, advertisementData, RSSI);
    }

}