在运行时更改Android Camera 2的Flash设置 [英] Changing Flash setting of Android Camera 2 at runtime

问题描述

基本上，我要做的是通过应用程序中的按钮单击更改CONTROL_AE_MODE。用户可以使用AUTO flash（ON_AUTO_FLASH），如果ON（ON_ALWAYS_FLASH）或OFF（CONTROL_AE_MODE_OFF）则关闭。

Basically, what I am trying to do is change the CONTROL_AE_MODE by button click in the app. The user can use AUTO flash(ON_AUTO_FLASH), turn if ON(ON_ALWAYS_FLASH), or OFF(CONTROL_AE_MODE_OFF).

在此示例中： https://github.com/googlesamples /android-Camera2Basic/blob/master/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java

第818行，他们设置闪光灯一次：

Line 818, they set the flash once:

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

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

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

                @Override
                public void onCaptureCompleted(@NonNull CameraCaptureSession session,
                                               @NonNull CaptureRequest request,
                                               @NonNull TotalCaptureResult result) {
                    showToast("Saved: " + mFile);
                    Log.d(TAG, mFile.toString());
                    unlockFocus();
                }
            };

            mCaptureSession.stopRepeating();
            mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);

然后在840行构建CaptureSession。

And then builds the CaptureSession at line 840.

有没有办法在预览后更改CONTROL_AE_MODE？

Is there a way to change the CONTROL_AE_MODE after the preview is made?

我尝试重新制作会话，这有点有用：

I have tried remaking the session, which kinda worked:

if(flashMode == CameraView.CAMERA_FLASH_ON){
            Log.e("CAMERA 2", "FLASH ON");
            mPreviewCaptureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
        }else if(flashMode == CameraView.CAMERA_FLASH_OFF){
            Log.e("CAMERA 2", "FLASH OFF");
            mPreviewCaptureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
        }else if(flashMode == CameraView.CAMERA_FLASH_AUTO){
            Log.e("CAMERA 2", "FLASH AUTO");
            mPreviewCaptureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
        }
        mFlashMode = flashMode;
        if (mCameraCaptureSession != null) {
            mCameraCaptureSession.close();
            mCameraCaptureSession = null;
       }
  createCameraPreviewSession();

出于某种原因，CONTROL_AE_MODE_OFF会将整个预览变为黑色。
我尝试在文档中查找更新方法，但没有找到任何内容。

For some reason, CONTROL_AE_MODE_OFF would turn the whole preview black. I tried looking in the docs for methods to update but haven't found anything.

非常感谢任何教程或文档。

Any tutorials or docs is much appreciated.

推荐答案

我不喜欢不知道为什么你的预览会变黑，但你不需要手动关闭捕获会话。从 .close（）方法的文档：

I don't know why your preview turn black, but you don't need to close capture session manually. From .close() method's docs:

使用 createCaptureSession（List，CameraCaptureSession.StateCallback，
Handler）直接不关闭是
快速切换到新会话的推荐方法，因为未更改的目标输出可以
be更有效地重用。

Using createCaptureSession(List , CameraCaptureSession.StateCallback, Handler) directly without closing is the recommended approach for quickly switching to a new session, since unchanged target outputs can be reused more efficiently.

因此，您可以重用现有的CaptureRequest.Builder，设置更改后的值，构建新的PreviewRequest并启动新的会话这个新请求，如下所示：

So you can reuse existing CaptureRequest.Builder, set your changed value, build new PreviewRequest and just start new session with this new request, like this:

try {
    // Change some capture settings
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
    // Build new request (we can't just edit existing one, as it is immutable)
    mPreviewRequest = mPreviewRequestBuilder.build();
    // Set new repeating request with our changed one
    mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
    e.printStackTrace();
}

它会更快（几乎没有任何可见的预览冻结）。

It will be much faster (almost without any visible freeze of preview).

这篇关于在运行时更改Android Camera 2的Flash设置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！