Android camera2手动闪光灯并不总是起作用

Question

我在Android 6.1，SDK23上使用新的camera2 api。

我有两个请求：预览和静态图像捕获请求。我想让它使闪光灯关闭每一个静态图像请求，但没有任何预闪光灯。现在，我的请求是这样的：

CaptureRequest.Builder requester = mCameraDevice.createCaptureRequest(mCameraDevice.TEMPLATE_STILL_CAPTURE);
        requester.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
        requester.set(CaptureRequest.CONTROL_CAPTURE_INTENT, CaptureRequest.CONTROL_CAPTURE_INTENT_STILL_CAPTURE);
        requester.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED);
        requester.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER, CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_CANCEL);
        requester.addTarget(mCaptureBuffer.getSurface());

mCaptureSession.capture(requester.build(), null, null);

Answer 1

flash_mode和control_ae_mode同时处于活动状态时有时会出现一些问题，因此我建议您将它们分开，不要关闭flash_mode以关闭并使用control_ae_mode控制Flash。因此，要设置不同的闪光灯模式，请使用如下所示：

int flashMode = yourDesireFlashModeKey;
        if (flashMode == CameraMetadata.FLASH_MODE_OFF) {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);

        } else if (flashMode == CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH) {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);

        } else if (flashMode == CameraMetadata.CONTROL_AE_MODE_ON_ALWAYS_FLASH) {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);

        } else if (flashMode == CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH_REDEYE) {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH_REDEYE);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
        }
        else if (flashMode == CameraMetadata.FLASH_MODE_OFF || flashMode == CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH) {

            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
        }
        else if (flashMode == CameraMetadata.CONTROL_AE_MODE_ON_ALWAYS_FLASH) {

            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_SINGLE);
        }

对于flash_mode，始终将flash保持为单个，在使用ae_mode_flash模式时将其关闭。

你可以在下一个链接中阅读更多关于它的信息。

希望它能帮助你；）