Android Camera开发实现可复用的相机组件

Android Camera开发实现可复用的相机组件攻略

简介

在本攻略中，我们将详细讲解如何开发一个可复用的相机组件，用于在Android应用中实现相机功能。我们将使用Android Camera2 API来实现这个组件。

步骤

步骤一：添加依赖

首先，我们需要在项目的build.gradle文件中添加以下依赖：

dependencies {
    implementation 'androidx.camera:camera-camera2:1.0.0'
    implementation 'androidx.camera:camera-lifecycle:1.0.0'
    implementation 'androidx.camera:camera-view:1.0.0-alpha25'
}

步骤二：创建相机预览布局

在布局文件中，我们需要创建一个用于显示相机预览的SurfaceView或TextureView。例如，我们可以创建一个名为camera_preview.xml的布局文件：

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

步骤三：初始化相机

在Activity或Fragment中，我们需要初始化相机并将预览视图与相机绑定。以下是一个示例代码：

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()

        val cameraSelector = CameraSelector.Builder()
            .requireLensFacing(CameraSelector.LENS_FACING_BACK)
            .build()

        val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
        preview.setSurfaceProvider(previewView.createSurfaceProvider(camera.cameraInfo))
    }, ContextCompat.getMainExecutor(this))
}

步骤四：处理相机权限

在AndroidManifest.xml文件中，确保已添加相机权限：

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

并在运行时请求相机权限：

private val REQUEST_CAMERA_PERMISSION = 1

private fun requestCameraPermission() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
        != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.CAMERA),
            REQUEST_CAMERA_PERMISSION)
    } else {
        startCamera()
    }
}

override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>,
    grantResults: IntArray) {
    if (requestCode == REQUEST_CAMERA_PERMISSION) {
        if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            startCamera()
        } else {
            Toast.makeText(this, \"Camera permission denied\", Toast.LENGTH_SHORT).show()
        }
    }
}

示例一：拍照功能

以下是一个示例代码，演示如何实现拍照功能：

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) {
                Toast.makeText(this@MainActivity, \"Photo saved\", Toast.LENGTH_SHORT).show()
            }

            override fun onError(exception: ImageCaptureException) {
                Toast.makeText(this@MainActivity, \"Photo capture failed\", Toast.LENGTH_SHORT).show()
            }
        })
}

示例二：录制视频功能

以下是一个示例代码，演示如何实现录制视频功能：

private lateinit var videoCapture: VideoCapture

private fun startRecording() {
    val videoCapture = VideoCapture.Builder()
        .build()

    val outputFile = File(externalMediaDirs.first(), \"video.mp4\")
    val outputOptions = VideoCapture.OutputFileOptions.Builder(outputFile).build()

    videoCapture.startRecording(outputOptions, ContextCompat.getMainExecutor(this),
        object : VideoCapture.OnVideoSavedCallback {
            override fun onVideoSaved(outputFileResults: VideoCapture.OutputFileResults) {
                Toast.makeText(this@MainActivity, \"Video saved\", Toast.LENGTH_SHORT).show()
            }

            override fun onError(videoCaptureError: Int, message: String, cause: Throwable?) {
                Toast.makeText(this@MainActivity, \"Video recording failed\", Toast.LENGTH_SHORT).show()
            }
        })
}

private fun stopRecording() {
    videoCapture.stopRecording()
}

结论

通过按照以上步骤，您可以开发一个可复用的相机组件，并实现拍照和录制视频功能。请根据您的需求进行相应的定制和扩展。

希望本攻略对您有所帮助！