我的应用程序使用Camera2 API尽可能快地获取帧 . 我们有一个开始/停止按钮来开始/停止捕获帧 . 焦点要么设置为自动，要么在捕获之前完成 . 如果在捕获之前完成了焦点，则在捕获期间必须禁用它 .

我正在使用它来成为焦点：

public void focusAt(Point point) {

    if(mCanAe || mCanAf) {

        int areaSize = 200;

        int ll = ((point.x * mActiveArraySize.right) - areaSize) / mTextureView.getWidth();
        int rr = ((point.y * mActiveArraySize.bottom) - areaSize) / mTextureView.getHeight();

        int focusLeft = clamp(ll, 0, mActiveArraySize.right);
        int focusBottom = clamp(rr, 0, mActiveArraySize.bottom);

        Rect newRect = new Rect(focusLeft, focusBottom, focusLeft + areaSize, focusBottom + areaSize);
        MeteringRectangle meteringRectangle = new MeteringRectangle(newRect, 1);
        final MeteringRectangle[] meteringRectangleArr = { meteringRectangle };

        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);

        try {
            mCaptureSession.capture(mPreviewRequestBuilder.build(), new CameraCaptureSession.CaptureCallback() {
                @Override
                public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {

                    if (mCanAe) {
                        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_REGIONS, meteringRectangleArr );
                    }

                    if (mCanAf) {
                        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_REGIONS, meteringRectangleArr );
                        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO);
                        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
                    }

                    try {

                        mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, mBackgroundHandler);
                    }
                    catch (CameraAccessException e) {

                        e.printStackTrace();
                    }
                }
            }, mBackgroundHandler);
        }
        catch (CameraAccessException e) { e.printStackTrace(); }
    }
}

捕获期间无法调用此函数 . 我认为这就足够了，但有时在捕捉过程中，Camera2会尝试集中注意力 .

有没有办法禁用焦点？

其他问题，是否必须在捕获之前锁定焦点？似乎没有这样做可以正常工作，但我想确定 .

编辑： grab 我这样做：

private void capture() {

    try {

        final CaptureRequest.Builder captureBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_ZERO_SHUTTER_LAG);
        captureBuilder.addTarget(mImageReader.getSurface());

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

        mCaptureSession.capture(captureBuilder.build(), null, mTakeImageBackgroundHandler);
    }
    catch (CameraAccessException e) {
        e.printStackTrace();
    }

保存帧后立即调用capture（）方法 .

android focus camera2