Question

您好我正在使用camera2basic示例来实现我的camera2应用程序。我找不到任何好的例子来实现触摸以使用camera2 api进行聚焦。目前，我用于触控的代码是：

    private void setFocusArea(MotionEvent event) {
    if (mCameraId == null) return;
    CameraManager cm = (CameraManager)getActivity().getSystemService(Context.CAMERA_SERVICE);
    CameraCharacteristics cc = null;
    try {
        cc = cm.getCameraCharacteristics(mCameraId);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }

    int myX = (int)event.getX();
    int myY = (int)event.getY();
    MeteringRectangle focusArea = new MeteringRectangle(myX-100,myY-100,200,200,MeteringRectangle.METERING_WEIGHT_DONT_CARE);
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
    try {
        mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
                mBackgroundHandler);
        // After this, the camera will go back to the normal state of preview.
        mState = STATE_PREVIEW;
    } catch (CameraAccessException e){
        // log
    }

    if (isMeteringAreaAESupported(cc)) {
        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_REGIONS,
                new MeteringRectangle[]{focusArea});
    }
    if (isMeteringAreaAFSupported(cc)) {
        mPreviewRequestBuilder
                .set(CaptureRequest.CONTROL_AF_REGIONS, new MeteringRectangle[]{focusArea});
        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
                CaptureRequest.CONTROL_AF_MODE_AUTO);
    }
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
            CameraMetadata.CONTROL_AF_TRIGGER_START);
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
            CameraMetadata.CONTROL_AE_PRECAPTURE_TRIGGER_START);
    try {
        mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), mCaptureCallback,
                mBackgroundHandler);
        mManualFocusEngaged = true;
    } catch (CameraAccessException e) {
        // error handling
    }
}

但问题在于它显示出奇怪的行为，其上的自动闪光不断重复自动对焦序列无限次，而且它似乎并不专注于触摸区域。我试过改变

mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);

为：

mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);

这停止了重复的自动对焦序列，但它仍然没有对焦于触摸区域，并且闪光灯只闪烁不到一秒而不是正常的对焦序列。请帮我解决这个问题，或者引导我进行工作，以便集中注意力。感谢

Answer 1

您的问题是设置AF区域控制。

计算要设置焦点的区域
停止当前会话mPreviewSession.stopRepeating()

启动自动对焦触发！

3.1。安全地启动AF区域IDLE

3.2。然后启动自动对焦触发

    mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_IDLE);
    mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);

捕获一次即可应用您的设置

检查是否支持AF和AE区域，如果受支持，请应用此区域

if ( isMeteringAreaAESupported()) {
    //System.out.println("AE regions are supported");
    mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AE_REGIONS, new MeteringRectangle[]{focusArea});
}
if (  isMeteringAreaAFSupported()) {
    //System.out.println("AF regions are supported");

    mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_REGIONS, new MeteringRectangle[]{focusArea});
    mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO);
}

再次捕捉一次即可设置焦点

mPreviewCaptureSession.capture（mCaptureRequestBuilder.build（），mCaptureCallback，mBackgroundHandler）;

在mCaptureCallback内，您应该取消AF触发，但是文档显示AF触发在某些设备中可以为空，所以我确实喜欢

mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_IDLE);
mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, null);

最后一件事是mPreviewCaptureSession.setRepeatingRequest(mCaptureRequestBuilder.build(), null, mBackgroundHandler);

希望有帮助。享受编码

Android camera2 api触控焦点的例子？

1 个答案: