void BindScan(ProcessCameraProvider cameraProvider, int width, int height)
{
var preview = new Preview.Builder().Build();
// 绑定预览
preview.SetSurfaceProvider(binding !.previewView.SurfaceProvider);
// 使用后置相机
var cameraSelector = new CameraSelector.Builder()
.RequireLensFacing(CameraSelector.LensFacingBack)
.Build();
// 绑定图片扫描解析
var imageAnalysis = new ImageAnalysis.Builder()
.SetTargetResolution(new(width, height))
.SetBackpressureStrategy(ImageAnalysis.StrategyKeepOnlyLatest)
.Build();
// 绑定图片扫描解析
analyser = new((barCodes, imageWidth, imageHeight) =>
{
// 解绑当前所有相机操作
cameraProvider.UnbindAll();
ScanCompletedHandler?.Invoke(barCodes.Select(x => x.GetRawBytes()));
ScanCompletedHandler = null;
Finish();
});
imageAnalysis.SetAnalyzer(Executors.NewSingleThreadExecutor(), analyser);
camera = cameraProvider.BindToLifecycle(this, cameraSelector, imageAnalysis, preview);
}
private void FindAndOpenCamera()
{
bool cameraPermissions = CheckCameraPermissions();
if (!cameraPermissions)
{
return;
}
string errorMessage = "Unknown error";
bool foundCamera = false;
IListenableFuture cameraProviderFuture = ProcessCameraProvider.GetInstance(this);
cameraProviderFuture.AddListener(new Runnable(() =>
{
// Camera provider is now guaranteed to be available
mCameraProvider = cameraProviderFuture.Get() as ProcessCameraProvider;
try
{
// Find first back-facing camera that has necessary capability.
CameraSelector cameraSelector = new CameraSelector.Builder().RequireLensFacing((int)mLensFacing).Build();
// Find a good size for output - largest 4:3 aspect ratio that's less than 720p
Preview.Builder previewBuilder = new Preview.Builder()
.SetTargetAspectRatio(AspectRatio.Ratio43);
Camera2Interop.Extender previewExtender = new Camera2Interop.Extender(previewBuilder);
previewExtender.SetSessionCaptureCallback(mCaptureCallback);
Preview preview = previewBuilder.Build();
// Must unbind the use-cases before rebinding them
mCameraProvider.UnbindAll();
ICamera camera = mCameraProvider.BindToLifecycle(
this as ILifecycleOwner, cameraSelector, preview);
if (camera != null)
{
// Found suitable camera - get info, open, and set up outputs
mCameraInfo = camera.CameraInfo;
mCameraControl = camera.CameraControl;
preview.SetSurfaceProvider(this);
foundCamera = true;
}
if (!foundCamera)
{
errorMessage = GetString(Resource.String.camera_no_good);
}
SwitchRenderMode(0);
}
catch (CameraAccessException e)
{
errorMessage = GetErrorString(e);
}
if (!foundCamera)
{
ShowErrorDialog(errorMessage);
}
}), ContextCompat.GetMainExecutor(this));
}
protected override void OnPause()
{
base.OnPause();
// Wait until camera is closed to ensure the next application can open it
if (mCameraProvider != null)
{
mCameraProvider.UnbindAll();
mCameraProvider = null;
}
}
private void BindCameraUseCases()
{
var metrics = new DisplayMetrics();
_previewView.Display !.GetRealMetrics(metrics);
var rotation = GetRotation(_previewView.Display.Rotation);
var cameraSelector = new CameraSelector.Builder().RequireLensFacing(CameraSelector.LensFacingBack)
.Build();
var aspectRatio = AspectRatio(metrics.WidthPixels, metrics.HeightPixels);
_preview = new Preview.Builder()
.SetTargetRotation(rotation)
.SetTargetAspectRatio(aspectRatio)
.Build();
_imageCapture = new ImageCapture.Builder()
.SetCaptureMode(ImageCapture.CaptureModeMinimizeLatency)
.SetTargetRotation(rotation)
.SetTargetAspectRatio(aspectRatio)
.Build();
var imageAnalyzer = new ImageAnalysis.Builder()
.SetTargetRotation(rotation)
.SetTargetAspectRatio(aspectRatio)
.Build();
imageAnalyzer.SetAnalyzer(_cameraExecutor, new LuminosityAnalyzer(this));
_cameraProvider.UnbindAll();
try
{
_camera = _cameraProvider.BindToLifecycle(this, cameraSelector, _preview, _imageCapture, imageAnalyzer);
_preview.SetSurfaceProvider(_previewView.SurfaceProvider);
}
catch (Java.Lang.Exception ex)
{
Log.Error(TAG, "Use case binding failed", ex);
}
}
// Declare and bind preview, capture and analysis use cases
private void BindCameraUseCases()
{
// Get screen metrics used to setup camera for full screen resolution
var metrics = new DisplayMetrics();
viewFinder.Display.GetRealMetrics(metrics);
Log.Debug(Tag, "Screen metrics: " + metrics);
var screenAspectRatio = AspectRatio(metrics.WidthPixels, metrics.HeightPixels);
Log.Debug(Tag, "Preview aspect ratio: " + screenAspectRatio);
var rotation = viewFinder.Display.Rotation;
// CameraProvider
if (cameraProvider == null)
{
throw new Java.Lang.IllegalStateException("Camera initialization failed.");
}
// CameraSelector
var cameraSelector = (new CameraSelector.Builder()).RequireLensFacing(lensFacing).Build();
// Preview
preview = new Preview.Builder()
// We request aspect ratio but no resolution
.SetTargetAspectRatio(screenAspectRatio)
// Set initial target rotation
.SetTargetRotation((int)rotation)
.Build();
// ImageCapture
imageCapture = new ImageCapture.Builder()
.SetCaptureMode(ImageCapture.CaptureModeMinimizeLatency)
// We request aspect ratio but no resolution to match preview config, but letting
// CameraX optimize for whatever specific resolution best fits our use cases
.SetTargetAspectRatio(screenAspectRatio)
// Set initial target rotation, we will have to call this again if rotation changes
// during the lifecycle of this use case
.SetTargetRotation((int)rotation)
.Build();
// ImageAnalysis
imageAnalyzer = new ImageAnalysis.Builder()
// We request aspect ratio but no resolution
.SetTargetAspectRatio(screenAspectRatio)
// Set initial target rotation, we will have to call this again if rotation changes
// during the lifecycle of this use case
.SetTargetRotation((int)rotation)
.Build();
// The analyzer can then be assigned to the instance
imageAnalyzer.SetAnalyzer(cameraExecutor, new LuminosityAnalyzer(
(double luma) => {
// Values returned from our analyzer are passed to the attached listener
// We log image analysis results here - you should do something useful
// instead!
Log.Debug(Tag, "Average luminosity: " + luma.ToString("0.00"));
})
);
// Must unbind the use-cases before rebinding them
cameraProvider.UnbindAll();
try
{
// A variable number of use-cases can be passed here -
// camera provides access to CameraControl & CameraInfo
camera = cameraProvider.BindToLifecycle(
(ILifecycleOwner)this, cameraSelector, preview, imageCapture, imageAnalyzer);
// Attach the viewfinder's surface provider to preview use case
preview?.SetSurfaceProvider(viewFinder.SurfaceProvider);
}
catch (Java.Lang.Exception exc)
{
Log.Error(Tag, "Use case binding failed: " + exc);
}
}