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java 如何实现拍照

2026-03-25 05:41:12Java

使用 Android Camera API 实现拍照

在 Android 应用中实现拍照功能，可以通过 Camera API 或 CameraX 库来完成。以下是两种常见方法的实现步骤。

使用 Camera API

添加权限 在 AndroidManifest.xml 中添加相机和存储权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

检查权限 在 Activity 中动态请求权限：

if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) 
 != PackageManager.PERMISSION_GRANTED) {
 ActivityCompat.requestPermissions(this, 
     new String[]{Manifest.permission.CAMERA}, 
     REQUEST_CAMERA_PERMISSION);
}

打开相机 使用 Camera.open() 获取相机实例：
```
Camera camera = Camera.open();
```

设置预览 将相机预览绑定到 SurfaceView：

Camera.Parameters params = camera.getParameters();
camera.setParameters(params);
camera.setPreviewDisplay(surfaceHolder);
camera.startPreview();

拍照并保存 调用 takePicture() 方法：

camera.takePicture(null, null, new Camera.PictureCallback() {
 @Override
 public void onPictureTaken(byte[] data, Camera camera) {
     File pictureFile = new File(Environment.getExternalStorageDirectory(), "photo.jpg");
     try {
         FileOutputStream fos = new FileOutputStream(pictureFile);
         fos.write(data);
         fos.close();
     } catch (IOException e) {
         e.printStackTrace();
     }
 }
});

使用 CameraX 库

添加依赖 在 build.gradle 中添加 CameraX 依赖：

java 如何实现拍照

implementation "androidx.camera:camera-core:1.0.0"
implementation "androidx.camera:camera-camera2:1.0.0"
implementation "androidx.camera:camera-lifecycle:1.0.0"
implementation "androidx.camera:camera-view:1.0.0"

配置预览 创建 PreviewView 并绑定生命周期：


PreviewView previewView = findViewById(R.id.previewView);
ListenableFuture<ProcessCameraProvider> cameraProviderFuture = 
 ProcessCameraProvider.getInstance(this);

cameraProviderFuture.addListener(() -> { try { ProcessCameraProvider cameraProvider = cameraProviderFuture.get(); Preview preview = new Preview.Builder().build(); preview.setSurfaceProvider(previewView.getSurfaceProvider());

    CameraSelector cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA;
    cameraProvider.unbindAll();
    cameraProvider.bindToLifecycle(
        this, cameraSelector, preview);
} catch (Exception e) {
    e.printStackTrace();
}

}, ContextCompat.getMainExecutor(this));


3. 拍照实现
创建 `ImageCapture` 实例并调用 `takePicture()`：
```java
ImageCapture imageCapture = new ImageCapture.Builder()
    .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
    .build();

cameraProvider.bindToLifecycle(
    this, cameraSelector, preview, imageCapture);

imageCapture.takePicture(
    ContextCompat.getMainExecutor(this),
    new ImageCapture.OnImageCapturedCallback() {
        @Override
        public void onCaptureSuccess(ImageProxy image) {
            // 处理拍照结果
            super.onCaptureSuccess(image);
        }
    });