以下是使用Android Camera2 API在4:3的宽高比下进行预览和捕获，但宽度大于高度的代码示例：

首先，在XML布局文件中添加一个TextureView来显示相机预览：

然后，在Activity或Fragment中获取TextureView并设置其宽高比：

private TextureView textureView;
private int previewWidth = 0;
private int previewHeight = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    textureView = findViewById(R.id.textureView);
    textureView.setSurfaceTextureListener(surfaceTextureListener);
}

private TextureView.SurfaceTextureListener surfaceTextureListener = new TextureView.SurfaceTextureListener() {
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int width, int height) {
        // 设置预览宽高比为4:3
        previewWidth = width;
        previewHeight = height * 4 / 3;
        
        // 打开相机并开始预览
        openCamera(previewWidth, previewHeight);
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int width, int height) {
        // 更新预览宽高
        previewWidth = width;
        previewHeight = height * 4 / 3;
        
        // 重新配置相机预览大小
        configureTransform(width, height);
    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        // 释放相机资源
        closeCamera();
        return true;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
        // 相机预览帧可用时触发
    }
};

接下来，使用CameraManager打开相机并创建一个CaptureSession进行预览和捕获：

private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSession;
private CaptureRequest.Builder captureRequestBuilder;

private void openCamera(int width, int height) {
    CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    String cameraId = null;
    
    try {
        // 获取可用的相机列表
        String[] cameraIds = cameraManager.getCameraIdList();
        
        // 遍历相机列表，找到后置摄像头
        for (String id : cameraIds) {
            CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(id);
            if (characteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_BACK) {
                cameraId = id;
                break;
            }
        }
        
        // 打开相机
        cameraManager.openCamera(cameraId, cameraStateCallback, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private CameraDevice.StateCallback cameraStateCallback = new CameraDevice.StateCallback() {
    @Override
    public void onOpened(@NonNull CameraDevice camera) {
        cameraDevice = camera;
        
        // 创建预览会话
        createCameraPreviewSession();
    }

    @Override
    public void onDisconnected(@NonNull CameraDevice camera) {
        cameraDevice.close();
        cameraDevice = null;
    }

    @Override
    public void onError(@NonNull CameraDevice camera, int error) {
        cameraDevice.close();
        cameraDevice = null;
    }
};

private void createCameraPreviewSession() {
    try {
        SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
        surfaceTexture.setDefaultBufferSize(previewWidth, previewHeight);
        
        Surface previewSurface = new Surface(surfaceTexture);
        
        captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        captureRequestBuilder.addTarget(previewSurface);
        
        cameraDevice.createCaptureSession(Arrays.asList(previewSurface), captureSessionStateCallback, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private CameraCaptureSession.StateCallback captureSessionStateCallback = new CameraCaptureSession.StateCallback() {
    @Override
    public void onConfigured(@NonNull CameraCaptureSession session) {
        if (cameraDevice == null) {
            return;
        }
        
        cameraCaptureSession = session;
        
        try {
            captureRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
            
            cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), captureSessionCapture