前言

kotlin使用CameraX实现录制视频
实现效果：
录制视频，点击对焦，录制完成后在手机相册中即可找到录制的视频
在这里插入图片描述

一、添加依赖

包括camerax的依赖自身和用于权限申请的permissionx依赖
camerax自身依赖可以在官方文档中查阅最新版本

// CameraX core library using the camera2 implementation
    def camerax_version = "1.2.0-alpha02" //1.2.0-alpha02
// The following line is optional, as the core library is included indirectly by camera-camera2
    implementation "androidx.camera:camera-core:${camerax_version}"
    implementation "androidx.camera:camera-camera2:${camerax_version}"
// If you want to additionally use the CameraX Lifecycle library
    implementation "androidx.camera:camera-lifecycle:${camerax_version}"
// If you want to additionally use the CameraX VideoCapture library
    implementation "androidx.camera:camera-video:${camerax_version}"
// If you want to additionally use the CameraX View class
    implementation "androidx.camera:camera-view:${camerax_version}"
// If you want to additionally add CameraX ML Kit Vision Integration
    implementation "androidx.camera:camera-mlkit-vision:${camerax_version}"
// If you want to additionally use the CameraX Extensions library
    implementation "androidx.camera:camera-extensions:${camerax_version}"
//权限请求 支持Androidx
    implementation 'com.guolindev.permissionx:permissionx:1.6.4'

二、权限申请

1.Manifest配置文件中

代码如下（示例）：

<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" /> <!-- 摄像头权限 -->
    <uses-permission android:name="android.permission.CAMERA" /> <!-- 具备摄像头 -->
    <uses-feature android:name="android.hardware.camera.any" /> <!-- 存储图像或者视频权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <!-- 录制音频权限 -->
    <uses-permission android:name="android.permission.RECORD_AUDIO" />

这里若需要读取相册中的文件进行上传等操作时需要在application中添加：

android:requestLegacyExternalStorage="true"

2.Activity中动态申请权限

代码如下（示例）：

//权限申请
        PermissionX.init(this).permissions(
            Manifest.permission.CAMERA,
            Manifest.permission.WRITE_EXTERNAL_STORAGE,
            Manifest.permission.READ_EXTERNAL_STORAGE,
            Manifest.permission.RECORD_AUDIO)
            .request{ allGranted, deniedList, _ ->
                if(allGranted){
                    //若权限申请成功
                    //启动预览
                    setUpCamera( binding.previewView )

                    //按键监听事件
                    listener()
                }
                else{
                    Toast.makeText(this," You denied ${deniedList}", Toast.LENGTH_SHORT).show()
                }
            }

这里使用的viewBinding进行的布局绑定binding.previewView即为布局文件中的预览控件

3.布局文件

主要是PreviewView用以相机预览

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbarvideo"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:background="@color/colorPrimary"
        app:layout_collapseMode="pin">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="25dp"
            android:text="录制视频">

        </TextView>
    </androidx.appcompat.widget.Toolbar>


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

    <ImageView
        android:id="@+id/recording"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:src="@drawable/start"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true"
        android:foreground="?android:attr/selectableItemBackground"/>


</RelativeLayout>

三、功能实现

1.预览

setUpCamera函数具体实现

private fun setUpCamera(previewView: PreviewView) {

        val camerProviderFuture : ListenableFuture<ProcessCameraProvider> =
            ProcessCameraProvider.getInstance(this)
        camerProviderFuture.addListener({
            try {
                //绑定相机生命周期
                cameraProvider = camerProviderFuture.get()
                bindPreview(cameraProvider, previewView)
            }catch (e: Exception){
                e.printStackTrace()
            }
        }, ContextCompat.getMainExecutor(this))

    }
    @SuppressLint("RestrictedApi")
    private fun bindPreview(
        cameraProvider: ProcessCameraProvider,
        previewView: PreviewView)
    {
        //重新绑定前取消绑定用例
        cameraProvider.unbindAll()

        //设置预览
        preview = Preview.Builder().build()

        videoCapture = VideoCapture.Builder()
            .setVideoFrameRate(25)
            .setBitRate(3*1024*1024)
            .build()

        camera = cameraProvider.bindToLifecycle(
            this,
            CameraSelector.DEFAULT_BACK_CAMERA, preview, videoCapture
        )
        preview?.setSurfaceProvider(previewView.surfaceProvider)

    }

2.录制

oncreate()中添加监听事件

binding.recording.setOnClickListener {
            //开始录制

            if(!inRecording){
                startRecording()
                inRecording = true
                binding.recording.setImageResource(R.drawable.stop)
            }else{
                videoCapture?.stopRecording() //这里为结束录制方法
                binding.recording.setImageResource(R.drawable.start)
                inRecording = false
            }
        }

startRecording函数实现

@SuppressLint("RestrictedApi", "MissingPermission")
    private fun startRecording(){
        val contentValues = ContentValues()
        contentValues.put(
            MediaStore.MediaColumns.DISPLAY_NAME,
            RECORDED_FILE_NAME+"_"+System.currentTimeMillis()
        )
        contentValues.put(MediaStore.MediaColumns.MIME_TYPE,RECORDED_FILE_NAME_END)

        val outputFileOptions = VideoCapture.OutputFileOptions.Builder(
            contentResolver,
            MediaStore.Video.Media.EXTERNAL_CONTENT_URI, contentValues
        ).build()
        videoCapture?.startRecording(
            outputFileOptions,
            ContextCompat.getMainExecutor(this),
            object : VideoCapture.OnVideoSavedCallback{
                override fun onVideoSaved(outputFileResults: VideoCapture.OutputFileResults) {
                    val proj = arrayOf(MediaStore.Images.Media.DATA)
                    val actualimagecursor = managedQuery(outputFileResults.savedUri, proj, null, null, null)
                    val actual_image_column_index = actualimagecursor.getColumnIndexOrThrow(
                        MediaStore.Images.Media.DATA);
                    actualimagecursor.moveToFirst();
                    val img_path = actualimagecursor.getString(actual_image_column_index);
                    Log.i("TAG", "视频路径: " + img_path);

                    Log.i("TAG", "视频保存成功: ${outputFileResults.savedUri}")
                }

                override fun onError(videoCaptureError: Int, message: String, cause: Throwable?) {
                    Log.i("TAG", "出现异常 cause:$cause")
                }
            }
        )
    }

2.对焦功能(附加)

添加监听事件

//点击对焦
        binding.previewView.setOnTouchListener { view , event ->
            val action = FocusMeteringAction.Builder(
                binding.previewView.meteringPointFactory.createPoint(event.x, event.y)
            ).build();

            showTapView(event.x.toInt(), event.y.toInt())
            camera?.cameraControl?.startFocusAndMetering((action))

            true
        }

showTapView函数实现

//显示对焦图标
    private fun showTapView( x:Int, y:Int ) {
        val popupWindow = PopupWindow(
            100,
            100

        )

        val imageView = ImageView(this)
        imageView.setImageResource(R.drawable.ic_focus_view)

        popupWindow.contentView = imageView
        popupWindow.showAsDropDown(binding.previewView, x,y)
        binding.previewView.postDelayed({popupWindow.dismiss()}, 600)
        binding.previewView.playSoundEffect(SoundEffectConstants.CLICK)

    }