Mein Problem besteht darin, dass mein captureBuilder den ausgewählten Blitzmodus nicht festlegt, wenn ich zwischen verschiedenen Blitzmodi umschalte und dann ein Bild aufnehmen möchte. Es funktioniert nur, wenn ich die Kamera schließe und wieder öffne.

Ich nahm diehttps: //github.com/googlesamples/android-Camera2Basi als Ausgangspunkt.

meine Methode:

   private void captureStillPicture() {
  try {
     final Activity activity = (Activity) context;
     if (null == activity || null == mCameraDevice) {
        return;
     }
     // This is the CaptureRequest.Builder that we use to take a picture.
     CaptureRequest.Builder captureBuilder =
           mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
     captureBuilder.addTarget(mImageReader.getSurface());

     // Use the same AE and AF modes as the preview.
     captureBuilder.set(CaptureRequest.CONTROL_AF_MODE,
           CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
     setCurrentFlash(captureBuilder);

     // Orientation
     int rotation = activity.getWindowManager()
           .getDefaultDisplay()
           .getRotation();
     captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getOrientation(rotation));

     CameraCaptureSession.CaptureCallback captureCallback =
           new CameraCaptureSession.CaptureCallback() {

              @Override
              public void onCaptureCompleted(@NonNull CameraCaptureSession session,
                    @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
                 super.onCaptureCompleted(session, request, result);
                 Toast.makeText(context, "image captured", Toast.LENGTH_SHORT)
                       .show();
                 unlockFocus();
              }
           };

              mCaptureSession.stopRepeating();
     mCaptureSession.capture(captureBuilder.build(), captureCallback, null);
  } catch (CameraAccessException e) {
     Log.e(this.getClass()
           .getSimpleName(), e.getMessage(), e);
  }

Dies ist die setCurrentFlash-Methode:

   private void setCurrentFlash(CaptureRequest.Builder requestBuilder) {
  if (mFlashSupported) {
     switch (flashMode.name()) {
        case FLASH_AUTO:
           requestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
                 CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
           break;
        case FLASH_ON:
           requestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
                 CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
           break;
        case FLASH_OFF:
           requestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
           break;
        default:
           requestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
                 CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
           break;
     }
  }

Haben Sie eine Idee, warum der Builder den Blitz vor der Aufnahme nicht richtig einstellt?

*****BEARBEITE *****

Behobenes Problem durch Setzen des Flashs auf previewRequestBuilder beim Aufrufen von runPrecaptureSequence (), wie von Eddy Talvala vorgeschlagen

   private void runPrecaptureSequence() {
  try {
     // This is how to tell the camera to trigger.
     setCurrentFlash(previewRequestBuilder);
     previewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
           CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
     // Tell #mCaptureCallback to wait for the precapture sequence to be set.
     state = STATE_WAITING_PRECAPTURE;
     captureSession.capture(previewRequestBuilder.build(), mCaptureCallback, backgroundHandler);
  } catch (CameraAccessException e) {
     e.printStackTrace();
  }