Android Camera2 API切换回前置摄像头 [英] Android Camera2 API switch back - front cameras

问题描述

我正在创建使用新的camera2 API捕获视频的自定义摄像头。

I'm creating a custom camera capturing videos with the new camera2 API.

我的代码强烈受到Google提供的代码启发此处。我的相机预览有一个按钮，从后面切换到前面的相机，然后从前面到后面的相机。
默认情况下，背照相机会启动相机预览活动。

My code is strongly inspired from the code provided by Google here. My camera preview has a button to switch from back to front camera and then from front to back camera. The "camera preview" activity is launched with the back camera by default.

由于某种原因，当我点击切换/切换相机按钮第一次，它带来的是前置摄像头，因为它应该，但是每次我再次点击，开关/交换不再工作：预览（前置摄像头）褪色一点位，如果发生了事情，但它仍然在当前选择（前）相机。

For some reason, when I click on the "switch/swap camera" button for the first time, it brings be to the front camera as it should, BUT everytime I click again, the switch/swap doesn't work anymore: the preview (on the front camera) fades a little bit, like if something is happening, but it remains on the currently selected (front) camera.

这是我的代码：

在 RecordVideoFragment ， onViewCreated ：

//  Switch camera button
        switchCameraButton = (ImageButton) view.findViewById(R.id.button_switch_camera);
        // Listener for Switch cameras button
        switchCameraButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                switchCameras();
            }
        });

这里是 switchCameras（） ：

private void  switchCameras() {
        mCameraOpenCloseLock.release();
        mCameraDevice.close();

        CameraManager mCameraManager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);
        try {
            String mCameraId = mCameraManager.getCameraIdList()[0];
            if (mCameraId.equals("0")) {   // If currently on FRONT camera (0 = CameraCharacteristics.LENS_FACING_FRONT)
                mCameraId = "1";           // switch to BACK camera (1 = CameraCharacteristics.LENS_FACING_BACK)
                switchCameraButton.setImageResource(R.drawable.ic_camera_front);
            } else {  // If currently on BACK camera
                mCameraId = "0"; // switch to front camera
                switchCameraButton.setImageResource(R.drawable.ic_camera_back);
            }
            try {
                if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA)
                        == PackageManager.PERMISSION_GRANTED) {
                    mCameraManager.openCamera(mCameraId, mStateCallback, null);
                } else {
                    requestVideoPermissions();
                }
            } catch (CameraAccessException e) {
                e.printStackTrace();
            }
        } catch (CameraAccessException e) {
            Toast.makeText(getActivity(), "Cannot access the camera.", Toast.LENGTH_SHORT).show();
            getActivity().finish();
        }
    }

如果你对发生什么我。我一直在探讨这个天。非常感谢。

If you have any idea on what's happening that would save me. I have been bugging on this for days. Thank you very much

推荐答案

您需要做的是引入新的变量：

What you need to do is introduce new variables:

public static final String CAMERA_FRONT = "1";
public static final String CAMERA_BACK = "0";

private String cameraId = CAMERA_BACK;

删除 cameraId 本地变量从 openCamera 方法。

public void switchCamera() {
    if (cameraId.equals(CAMERA_FRONT)) {
        cameraId = CAMERA_BACK;
        closeCamera();
        reopenCamera();
        switchCameraButton.setImageResource(R.drawable.ic_camera_front);

    } else if (cameraId.equals(CAMERA_BACK)) {
        cameraId = CAMERA_FRONT;
        closeCamera();
        reopenCamera();
        switchCameraButton.setImageResource(R.drawable.ic_camera_back);
    }
}

public void reopenCamera() {
    if (mTextureView.isAvailable()) {
        openCamera(mTextureView.getWidth(), mTextureView.getHeight());
    } else {
        mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
    }
}

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