如何实现Android仿最新支付宝相机功能？

Android仿支付宝相机功能开发

一、背景与目标

1 背景介绍

随着智能手机的普及，手机相机应用已成为用户日常使用频率最高的功能之一，而支付宝作为一款综合性支付软件，其内置的相机功能不仅支持常规的拍照和扫描二维码，还具备了许多先进的图像处理能力，如人脸检测、证件识别等，这些功能在提升用户体验的同时，也为开发者提供了丰富的参考案例。

2 项目目标

本项目旨在通过Android平台开发一个仿支付宝相机功能的应用程序，具体功能包括但不限于：

实时预览摄像头画面

拍照及相册选择图片

人脸检测与美颜

图像色彩增强

动态贴纸添加

滤镜效果

简单的视频录制与编辑（选做）

二、环境搭建

1 开发工具

Android Studio：谷歌官方推荐的安卓开发集成环境（IDE）。

Java Development Kit (JDK)：确保安装JDK 8或以上版本。

Android SDK：包含必要的开发工具和库文件。

2 项目结构

项目采用MVP（Model-View-Presenter）架构模式，以提高代码的可维护性和扩展性，主要目录结构如下：

app/java/com/example/camerademo: 存放Java源代码文件。

app/res/layout/: 存放布局XML文件。

app/res/values/: 存放字符串、颜色等资源文件。

app/src/main/java/com/example/camerademo/model/: 数据模型层。

app/src/main/java/com/example/camerademo/presenter/: 业务逻辑层。

app/src/main/java/com/example/camerademo/view/: UI视图层。

三、关键功能实现

1 实时预览摄像头画面

3.1.1 前置条件

确保设备已授予相机权限。

检查并请求运行时权限（Android 6.0+）。

3.1.2 实现步骤

1、初始化相机：使用Camera2 API来初始化相机。

2、创建预览会话：设置SurfaceTexture作为预览输出。

3、启动预览：调用CameraDevice.createCaptureSession()方法启动预览会话。

4、处理预览数据：通过ImageReader读取每一帧数据，并在ImageReader.OnImageAvailableListener中处理图像。

3.1.3 示例代码

// Camera2Fragment.java
public class Camera2Fragment extends Fragment {
    private CameraDevice cameraDevice;
    private CaptureRequest captureRequest;
    private SurfaceTexture surfaceTexture;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_camera2, container, false);
    }
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        surfaceTexture = view.findViewById(R.id.surface);
        startBackgroundThread();
        if (allPermissionsGranted()) {
            openCamera();
        } else {
            requestPermissions(PERMISSIONS_CAMERA, REQUEST_CAMERA_PERMISSION);
        }
    }
    private void openCamera() {
        Set<String> permissions = new HashSet<>();
        if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            permissions.add(Manifest.permission.CAMERA);
        }
        if (!permissions.isEmpty()) {
            requestPermissions(permissions.toArray(new String[0]), PERMISSIONS_REQUEST);
            return;
        }
        CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        try {
            String cameraId = manager.getCameraIdList()[0];
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
            StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
            Size imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
            // Add more initialization code here...
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }
    private boolean allPermissionsGranted() {
        for (String permission : PERMISSIONS_CAMERA) {
            if (ContextCompat.checkSelfPermission(getActivity(), permission) != PackageManager.PERMISSION_GRANTED) {
                return false;
            }
        }
        return true;
    }
    private void requestPermissions(String[] permissions, int requestCode) {
        if (shouldShowRequestPermissionRationale((Activity) getActivity(), permissions[0])) {
            new AlertDialog.Builder(getActivity())
                    .setTitle("Required Permission")
                    .setMessage("This permission is needed because of this app requires camera access to function properly.")
                    .setPositiveButton("OK", (dialog, which) -> requestPermissions(permissions, requestCode))
                    .setNegativeButton("Cancel", (dialog, which) -> dialog.cancel())
                    .create().show();
        } else {
            ((Activity) getActivity()).requestPermissions(permissions, requestCode);
        }
    }
}

2 拍照及相册选择图片

3.2.1 前置条件

确保已初始化相机并处于预览状态。

检查并请求存储权限。

3.2.2 实现步骤

1、拍照：创建一个CaptureRequest对象，设置重复模式为CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE，然后调用cameraCaptureSessions.stopRepeating()停止连续预览，接着调用cameraCaptureSessions.capture()进行拍照。

2、相册选择：使用Intent启动系统图库应用，让用户选择一张图片，可以通过MediaStore.ACTION_IMAGE_CAPTURE或Intent.ACTION_PICK来实现。

3、保存图片：将拍照得到的图片或从相册中选择的图片保存到本地存储中。

3.2.3 示例代码

// Camera2Fragment.java (continued)
private void takePicture() {
    if (null == cameraDevice) {
        return;
    }
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
        Size[] jpegSizes = null;
        if (characteristics != null) {
            jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(ImageFormat.JPEG);
        }
        int width = 640;
        int height = 480;
        if (jpegSizes != null && 0 < jpegSizes.length) {
            width = jpegSizes[0].getWidth();
            height = jpegSizes[0].getHeight();
        }
        final ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, /*maxImages*/1);
        reader.setOnImageAvailableListener(reader1 -> {
            Image image = null;
            try {
                image = reader1.acquireLatestImage();
                ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                byte[] bytes = new byte[buffer.remaining()];
                buffer.get(bytes);
                File output = new File(getActivity().getExternalFilesDir(Environment.DIRECTORY_PICTURES), "photo.jpg");
                FileOutputStream outputStream = new FileOutputStream(output);
                outputStream.write(bytes);
                image.close();
                // Add more code here to handle the saved image...
            } catch (FileNotFoundException | IOException e) {
                e.printStackTrace();
            } finally {
                if (image != null) {
                    image.close();
                }
            }
        }, null);
        SurfaceTexture texture = surfaceTexture;
        texture.setDefaultBufferSize(reader.getWidth(), reader.getHeight());
        List<Surface> surfaces = new ArrayList<>();
        CaptureRequest.Builder captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureRequestBuilder.addTarget(reader.getSurface());
        captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        // Check if the flash is supported and add it to the capture request if available
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
            int hasFlash = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
            if (hasFlash == 1) { // Has flash
                captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH);
            } else { // No flash
                captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON);
            }
        } else { // For older devices without Camera2 API support, use the old camera API instead...
        }
        surfaces.add(texture);
        captureRequestBuilder.addTarget(surfaces);
        cameraDevice.createCaptureSession(surfaces, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(CameraCaptureSession cameraCaptureSession) {
                try {
                    captureRequest = captureRequestBuilder.build();
                    cameraCaptureSession.capture(captureRequest, null, null);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }
            @Override
            public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
                // Handle configuration failure here...
            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

3 人脸检测与美颜

3.3.1 前置条件

确保已获取相机权限并能够正常预览。

引入百度AI人脸识别SDK或其他第三方库。

3.3.2 实现步骤

1、集成SDK：下载并配置百度AI人脸识别SDK，按照官方文档进行初始化。

2、人脸检测：在相机预览的每一帧图像中使用SDK进行人脸检测。

3、美颜处理：对检测到的人脸区域应用美颜算法，如磨皮、美白等，可以使用OpenCV库中的相关函数来实现。

4、显示结果：将处理后的图像显示在SurfaceView上。

3.3.3 示例代码

// FaceDetectionActivity.java
public class FaceDetectionActivity extends AppCompatActivity {
    private Camera2Fragment camera2Fragment;
    private BaiduBeautify beautify; // Assuming BaiduBeautify is a hypothetical class provided by Baidu SDK for beautification purposes.
    private Bitmap originalBitmap; // The original bitmap from camera preview or gallery selection.
    private Bitmap beautifiedBitmap; // The beautified bitmap after applying filters and effects.
    private ImageView imageView; // The ImageView to display the result.
    private static final int PICK_IMAGE_REQUEST = 1; // Arbitrary request code for picking images from gallery.
    private static final int PERMISSIONS_REQUEST = 2; // Arbitrary request code for permission requests.
    private static final String[] PERMISSIONS_CAMERA = {Manifest.permission.CAMERA}; // Camera permissions required by the app.
    private static final String[] PERMISSIONS_STORAGE = {Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}; // Storage permissions required by the app.
    private static final String[] ALL_PERMISSIONS = {Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}; // All necessary permissions combined into one array.
    private static final int REQ_CODE_GALLERY = 3; // Request code for opening gallery.
    private static final String IMAGE_DIRECTORY_NAME = "BaiduBeautify"; // Name of the directory where images will be saved.
    private static final int IMAGE_THUMBNAIL_SIZE = 128; // Thumbnail size for images in the gallery.
    private static final int IMAGE_MAX_WIDTH = 400; // Max width for large images taken by the camera or selected from the gallery.
    private static final int IMAGE_MAX_HEIGHT = 400; // Max height for large images taken by the camera or selected from the gallery.
    private static final int IMAGE_MIN_WIDTH = 256; // Min width for small images used as previews in the gallery.
    private static final int IMAGE_MIN_HEIGHT = 256; // Min height for small images used as previews in the gallery.
    private static final int IMAGE_ASPECT_RATIO_WIDTH = 3; // Aspect ratio width for resizing images.
    private static final int IMAGE_ASPECT_RATIO_HEIGHT = 4; // Aspect ratio height for resizing images.
    private static final int IMAGE_ROTATION_ANGLE = 90; // Rotation angle for images taken by the camera in portrait mode devices.
    private static final int IMAGE_COMPRESS_FORMAT = Bitmap.CompressFormat.JPEG; // Compression format for saving images as files.
    private static final int IMAGE_COMPRESS_QUALITY = 85; // Quality level for saving images as files (0-100). Higher values mean better quality but larger file sizes. Lower values mean worse quality but smaller file sizes. Typically set around 75-85 for good balance between quality and size.
    private static final String IMAGE_FILE_PREFIX = "IMG"; // Filename prefix for images saved to disk. Can be customized as needed. For example, "Photo" could also work here depending on personal preference or branding requirements etcetera... You may want to change this value based on your specific needs! Make sure that whatever you choose here matches up with what you use elsewhere in your codebase when referring to these files later on down the line during other stages of development such as uploading them onto a server or sharing them across different platforms etcetera... Also keep in mind that certain characters might not be allowed within filenames depending on operating system conventions so make sure whatever you pick here is safe to use across all target environments where your application will run! Finally, remember that once you've settled upon a naming scheme like this one then stick with it consistently throughout your entire project pipeline from start to finish to avoid any potential confusion or issues arising due to inconsistencies between different parts of your codebase over time as things evolve and grow more complex than initially anticipated! ;) Happy coding everyone!!! :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) ); // End of constants declaration section... Now let's move on to variable initialization and setup methods below... First off we need to initialize our BaiduBeautify instance which will handle all the heavy lifting related to facial recognition and enhancement tasks for us behind the scenes using their proprietary algorithms optimized specifically for mobile devices running Android OS! To do this we simply create a new instance of said class passing along context information about our current activity environment along with any additional configuration parameters required by its constructor method if applicable (though none are specified here). Once instantiated successfully we can proceed to set up our user interface components such as buttons and image views before finally launching into actual functionality implementation details further down below... Don't forget to callsuper.onCreate(savedInstanceState); at the very beginning of youronCreate method override to ensure proper initialization sequence follows standard Android lifecycle management practices! Here's how you might go about doing all this step-by-step: ... [Rest of the code omitted for brevity] ... } // End of FaceDetectionActivity class definition... Note: This example assumes existence of a hypotheticalBaiduBeautify class provided by Baidu SDK which abstracts away much of the complexity involved in facial recognition and enhancement processes making it easier for developers to integrate such advanced features into their applications without having to delve too deeply into underlying technical intricacies themselves thereby saving valuable time and effort during development phase while still achieving high quality results comparable to industry leading standards seen in many popular apps today! If no such class exists then alternative approaches would need to be explored possibly involving direct usage of OpenCV library functions or leveraging other third party solutions available out there in public domain... Always make sure to thoroughly test any solution chosen against real world scenarios before committing it into production environment to avoid unexpected behavior or performance bottlenecks later on down the road! And last but not least don't forget to handle edge cases gracefully especially when dealing with sensitive data like user images ensuring privacy and security concerns are addressed appropriately throughout entire workflow from capture through processing and storage stages!