Android实现手机拍照功能

Android实现手机拍照功能攻略

1. 添加权限和依赖项

首先，在AndroidManifest.xml文件中添加相机权限：

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

然后，在app的build.gradle文件中添加相机依赖项：

implementation 'androidx.camera:camera-camera2:1.0.0'
implementation 'androidx.camera:camera-lifecycle:1.0.0'
implementation 'androidx.camera:camera-view:1.0.0-alpha24'

2. 创建相机预览界面

在布局文件中，添加一个PreviewView来显示相机预览：

<androidx.camera.view.PreviewView
    android:id=\"@+id/previewView\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"match_parent\" />

3. 初始化相机

在Activity或Fragment中，初始化相机并将其与PreviewView关联起来：

private lateinit var cameraProvider: ProcessCameraProvider
private lateinit var preview: Preview

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
    cameraProviderFuture.addListener({
        cameraProvider = cameraProviderFuture.get()

        preview = Preview.Builder().build()
        preview.setSurfaceProvider(previewView.createSurfaceProvider())

        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
        val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
    }, ContextCompat.getMainExecutor(this))
}

4. 拍照

添加一个按钮或其他触发拍照的UI元素，并在点击事件中执行拍照操作：

private lateinit var imageCapture: ImageCapture

private fun takePhoto() {
    val imageCapture = ImageCapture.Builder().build()

    val outputFile = File(externalMediaDirs.first(), \"photo.jpg\")
    val outputOptions = ImageCapture.OutputFileOptions.Builder(outputFile).build()

    imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this),
        object : ImageCapture.OnImageSavedCallback {
            override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
                // 图片保存成功后的处理逻辑
            }

            override fun onError(exception: ImageCaptureException) {
                // 拍照出错时的处理逻辑
            }
        })
}

示例说明

示例1：拍照并显示预览

class MainActivity : AppCompatActivity() {
    private lateinit var cameraProvider: ProcessCameraProvider
    private lateinit var preview: Preview

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val previewView = findViewById<PreviewView>(R.id.previewView)

        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener({
            cameraProvider = cameraProviderFuture.get()

            preview = Preview.Builder().build()
            preview.setSurfaceProvider(previewView.createSurfaceProvider())

            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
            val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
        }, ContextCompat.getMainExecutor(this))
    }

    fun takePhoto(view: View) {
        val imageCapture = ImageCapture.Builder().build()

        val outputFile = File(externalMediaDirs.first(), \"photo.jpg\")
        val outputOptions = ImageCapture.OutputFileOptions.Builder(outputFile).build()

        imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this),
            object : ImageCapture.OnImageSavedCallback {
                override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
                    // 图片保存成功后的处理逻辑
                }

                override fun onError(exception: ImageCaptureException) {
                    // 拍照出错时的处理逻辑
                }
            })
    }
}

示例2：自定义拍照界面

<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"match_parent\">

    <androidx.camera.view.PreviewView
        android:id=\"@+id/previewView\"
        android:layout_width=\"match_parent\"
        android:layout_height=\"match_parent\" />

    <Button
        android:id=\"@+id/captureButton\"
        android:layout_width=\"wrap_content\"
        android:layout_height=\"wrap_content\"
        android:layout_alignParentBottom=\"true\"
        android:layout_centerHorizontal=\"true\"
        android:layout_marginBottom=\"16dp\"
        android:text=\"拍照\"
        android:onClick=\"takePhoto\" />
</RelativeLayout>

class MainActivity : AppCompatActivity() {
    private lateinit var cameraProvider: ProcessCameraProvider
    private lateinit var preview: Preview

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val previewView = findViewById<PreviewView>(R.id.previewView)

        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener({
            cameraProvider = cameraProviderFuture.get()

            preview = Preview.Builder().build()
            preview.setSurfaceProvider(previewView.createSurfaceProvider())

            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
            val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
        }, ContextCompat.getMainExecutor(this))
    }

    fun takePhoto(view: View) {
        val imageCapture = ImageCapture.Builder().build()

        val outputFile = File(externalMediaDirs.first(), \"photo.jpg\")
        val outputOptions = ImageCapture.OutputFileOptions.Builder(outputFile).build()

        imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this),
            object : ImageCapture.OnImageSavedCallback {
                override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
                    // 图片保存成功后的处理逻辑
                }

                override fun onError(exception: ImageCaptureException) {
                    // 拍照出错时的处理逻辑
                }
            })
    }
}

以上是实现Android手机拍照功能的完整攻略，其中包含了两个示例说明。你可以根据自己的需求选择其中一种方式来实现。