android camerax怎样处理视频录制

Android CameraX 是一个用于处理相机功能的库，它提供了一种简单的方法来集成相机功能到您的应用程序中。要使用 CameraX 处理视频录制，您需要遵循以下步骤：

1. 添加依赖项

在您的项目的 build.gradle 文件中添加 CameraX 和 CameraX LiveData 依赖项：

dependencies {
    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'
    implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.1'
}

2. 配置 CameraX

在您的 Activity 或 Fragment 中，配置 CameraX 并设置预览和录制回调：

import android.Manifest
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.ImageProxy
import androidx.camera.core.VideoCapture
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {

    private lateinit var cameraProviderFuture: ProcessCameraProvider
    private lateinit var preview: Preview
    private lateinit var videoCapture: VideoCapture
    private lateinit var imageAnalyzer: ImageAnalysis

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

        // 检查权限
        if (hasPermissions()) {
            // 获取 CameraProvider
            cameraProviderFuture = ProcessCameraProvider.getInstance(this)
            cameraProviderFuture.addListener({
                val cameraProvider = cameraProviderFuture.get()
                bindPreviewAndRecord(cameraProvider)
            }, ContextCompat.getMainExecutor(this))
        }
    }

    private fun hasPermissions(): Boolean {
        return ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED &&
                ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED
    }

    private fun bindPreviewAndRecord(cameraProvider: ProcessCameraProvider) {
        // 创建预览
        preview = Preview.Builder().build()

        // 创建视频录制器
        videoCapture = VideoCapture.Builder().build()

        // 创建图像分析器
        imageAnalyzer = ImageAnalysis.Builder()
            .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
            .build()
            .also {
                it.setAnalyzer(CoroutineScope(Dispatchers.Default), ImageAnalyzer())
            }

        // 设置摄像头选择器
        val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()

        // 绑定预览和视频录制器到 CameraProvider
        cameraProvider.unbindAll()
        cameraProvider.bindToLifecycle(this, cameraSelector, preview, videoCapture, imageAnalyzer)
    }

    private inner class ImageAnalyzer : ImageAnalysis.Analyzer {
        override fun analyze(imageProxy: ImageProxy) {
            // 处理图像数据，例如识别物体、人脸等
            val mediaImage = imageProxy.image
            if (mediaImage != null) {
                // 在这里处理图像数据
            }
            imageProxy.close()
        }
    }
}

3. 开始和停止录制

在您的 Activity 或 Fragment 中，添加开始和停止录制的逻辑：

private var isRecording = false

private fun startRecording() {
    isRecording = true
    videoCapture.startRecording(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, object : VideoCapture.OnVideoSavedCallback {
        override fun onVideoSaved(outputFile: MediaStore.ImagesAndVideos.MediaFile) {
            // 视频已保存
        }

        override fun onError(exc: Exception) {
            // 处理错误
        }
    })
}

private fun stopRecording() {
    isRecording = false
    videoCapture.stopRecording()
}

现在，您已经成功地使用 CameraX 处理了视频录制。请注意，这是一个简化的示例，您可能需要根据您的需求进行调整。