通过camera2接口使用音量按钮进行摄像机变焦

// 获取相机设备
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
String cameraId = cameraManager.getCameraIdList()[0];
cameraManager.openCamera(cameraId, new CameraDevice.StateCallback() {
    @Override
    public void onOpened(@NonNull CameraDevice camera) {
        // 创建预览会话
        List<Surface> surfaces = new ArrayList<>();
        surfaces.add(previewSurface);
        camera.createCaptureSession(surfaces, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession session) {
                // 设置参数和配置
                CaptureRequest.Builder requestBuilder = camera.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
                requestBuilder.addTarget(previewSurface);
                session.setRepeatingRequest(requestBuilder.build(), null, null);
                
                // 监听音量按钮事件
                VolumeShutter volumeShutter = new VolumeShutter();
                volumeShutter.setOnVolumeButtonEventListener(new VolumeShutter.OnVolumeButtonEventListener() {
                    @Override
                    public void onVolumeButtonEvent() {
                        // 处理音量按钮事件
                        int zoomLevel = calculateZoomLevel(); // 计算变焦级别
                        requestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomLevel);
                        session.setRepeatingRequest(requestBuilder.build(), null, null);
                    }
                });
            }
            
            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession session) {
                // 配置失败处理
            }
        }, null);
    }
    
    @Override
    public void onDisconnected(@NonNull CameraDevice camera) {
        // 相机断开处理
    }
    
    @Override
    public void onError(@NonNull CameraDevice camera, int error) {
        // 相机错误处理
    }
});