static bool IsMediaMounted(Java.IO.File location) =>
Platform.HasApiLevel(BuildVersionCodes.Lollipop)
? AndroidEnvironment.GetExternalStorageState(location) == AndroidEnvironment.MediaMounted
#pragma warning disable CS0618 // Type or member is obsolete
: AndroidEnvironment.GetStorageState(location) == AndroidEnvironment.MediaMounted;
ISecretKey GetKey()
{
// check to see if we need to get our key from past-versions or newer versions.
// we want to use symmetric if we are >= 23 or we didn't set it previously.
useSymmetric = Preferences.Get(useSymmetricPreferenceKey, Platform.HasApiLevel(BuildVersionCodes.M), SecureStorage.Alias);
// If >= API 23 we can use the KeyStore's symmetric key
if (useSymmetric && !alwaysUseAsymmetricKey)
{
return(GetSymmetricKey());
}
// NOTE: KeyStore in < API 23 can only store asymmetric keys
// specifically, only RSA/ECB/PKCS1Padding
// So we will wrap our symmetric AES key we just generated
// with this and save the encrypted/wrapped key out to
// preferences for future use.
// ECB should be fine in this case as the AES key should be
// contained in one block.
// Get the asymmetric key pair
var keyPair = GetAsymmetricKeyPair();
var existingKeyStr = Preferences.Get(prefsMasterKey, null, alias);
if (!string.IsNullOrEmpty(existingKeyStr))
{
try
{
var wrappedKey = Convert.FromBase64String(existingKeyStr);
var unwrappedKey = UnwrapKey(wrappedKey, keyPair.Private);
var kp = unwrappedKey.JavaCast <ISecretKey>();
return(kp);
}
catch (InvalidKeyException ikEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Invalid Key. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ikEx.Message}");
}
catch (IllegalBlockSizeException ibsEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Illegal Block Size. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ibsEx.Message}");
}
catch (BadPaddingException paddingEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Bad Padding. This may be caused by system backup or upgrades. All secure storage items will now be removed. {paddingEx.Message}");
}
SecureStorage.RemoveAll();
}
var keyGenerator = KeyGenerator.GetInstance(aesAlgorithm);
var defSymmetricKey = keyGenerator.GenerateKey();
var newWrappedKey = WrapKey(defSymmetricKey, keyPair.Public);
Preferences.Set(prefsMasterKey, Convert.ToBase64String(newWrappedKey), alias);
return(defSymmetricKey);
}
static Task ToggleTorchAsync(bool switchOn)
{
return(Task.Run(() =>
{
lock (locker)
{
if (Platform.HasApiLevel(BuildVersionCodes.M) && !AlwaysUseCameraApi)
{
var cameraManager = Platform.CameraManager;
foreach (var id in cameraManager.GetCameraIdList())
{
var hasFlash = cameraManager.GetCameraCharacteristics(id).Get(CameraCharacteristics.FlashInfoAvailable);
if (Java.Lang.Boolean.True.Equals(hasFlash))
{
try
{
cameraManager.SetTorchMode(id, switchOn);
break;
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine($"Unable to SetTorchMode on {id}: {ex.Message}");
}
}
}
}
else
{
if (camera == null)
{
if (surface == null)
{
surface = new SurfaceTexture(0);
}
#pragma warning disable CS0618 // Camera types are deprecated in Android 10+
camera = Camera.Open();
// Nexus 5 and some devices require a preview texture
camera.SetPreviewTexture(surface);
}
var param = camera.GetParameters();
// Deprecated in an earlier android version
param.FlashMode = switchOn ? Camera.Parameters.FlashModeTorch : Camera.Parameters.FlashModeOff;
camera.SetParameters(param);
if (switchOn)
{
camera.StartPreview();
}
else
{
camera.StopPreview();
camera.Release();
camera.Dispose();
#pragma warning restore CS0618 // Type or member is obsolete
camera = null;
surface.Dispose();
surface = null;
}
}
}
}));
}
