跳到主要内容

相机开发

问题​

iOS 相机开发的核心 API 和流程？

答案​

AVCaptureSession​

拍照实现​

import AVFoundation

class CameraManager: NSObject {
    private let session = AVCaptureSession()
    private let photoOutput = AVCapturePhotoOutput()

    func setupCamera() {
        session.sessionPreset = .photo

        guard let camera = AVCaptureDevice.default(.builtInWideAngleCamera,
                                                    for: .video,
                                                    position: .back),
              let input = try? AVCaptureDeviceInput(device: camera) else { return }

        if session.canAddInput(input) { session.addInput(input) }
        if session.canAddOutput(photoOutput) { session.addOutput(photoOutput) }

        // 启动
        DispatchQueue.global(qos: .userInitiated).async {
            self.session.startRunning()
        }
    }

    func capturePhoto() {
        let settings = AVCapturePhotoSettings()
        settings.flashMode = .auto
        photoOutput.capturePhoto(with: settings, delegate: self)
    }
}

extension CameraManager: AVCapturePhotoCaptureDelegate {
    func photoOutput(_ output: AVCapturePhotoOutput,
                     didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
        guard let data = photo.fileDataRepresentation() else { return }
        let image = UIImage(data: data)
        // 使用图片
    }
}
权限

相机和麦克风需要在 Info.plist 声明 NSCameraUsageDescription 和 NSMicrophoneUsageDescription，并在代码中请求授权。

常见面试问题​

Q1: 前后摄像头切换怎么实现？​

答案：移除当前 input，创建新的 AVCaptureDeviceInput（切换 .front / .back），重新添加到 session。需要在 beginConfiguration() / commitConfiguration() 之间操作。

相关链接​