Android中CameraX的基本使用(Kotlin实现)
Andoird中拍照、录像是很常见的功能，但是系统相机的Api目前发生了很大的变化，有Camera1、Camera2、CameraX三个api,每个api的使用和方法都不一样，如果做过相机开发的小伙伴应该会很头疼这三个api在不同安卓系统手机的适配，由于目前的App有一部分工作涉及到这部分，所以总结了一下，目前由基础到深入慢慢总结.
一.简介：（官方介绍如下）
CameraX 是一个 Jetpack 支持库，旨在帮助您简化相机应用的开发工作。它提供一致且易用的 API 接口，适用于大多数 Android 设备，并可向后兼容至 Android 5.0（API 级别 21）。
具体内容可以参考官网介绍，网站地址为：
CameraX 概览 | Android 开发者 | Android Developers
二.优势：（参考官网）
易用性
图 1.CameraX 以 Android 5.0（API 级别 21）及更高版本为目标平台，涵盖了大多数 Android 设备
CameraX 引入了多个用例，使您可以专注于需要完成的任务，而无需花时间处理不同设备之间的细微差别。一些基本用例如下所示：
预览：在屏幕上显示图像
图像分析：无缝访问缓冲区中的图像以便在算法中使用，例如将其传入 MLKit
图片拍摄：保存优质图片
这些用例适用于搭载 Android 5.0（API 级别 21）或更高版本的所有设备，从而确保了同样的代码适用于市场中的大多数设备。
三.实战代码如下：
1.项目引入CameraX的依赖如下：
在项目的build.gradle导入如下配置：
// CameraX 核心库使用 camera2 实现
implementation "androidx.camera:camera-camera2:1.0.0-beta07"
// 可以使用CameraView
implementation "androidx.camera:camera-view:1.0.0-alpha14"
// 可以使用供应商扩展
implementation "androidx.camera:camera-extensions:1.0.0-alpha14"
//camerax的生命周期库
implementation "androidx.camera:camera-lifecycle:1.0.0-beta07"
2.项目的Application:
/**
* @auth: njb
* @date: 2021/10/20 16:19
* @desc: 描述
*/
public class MyApp extends Application {
public static MyApp app = null;
@Override
public void onCreate() {
super.onCreate();
app = this;
}
public static MyApp getInstance(){
return app;
}
}
3.MainActivity代码如下：
项目的主要3个功能方法：
3.1、拍照方法:startCamera()
/**
* 开始拍照
*/
private fun startCamera() {
cameraExecutor = Executors.newSingleThreadExecutor()
val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
cameraProviderFuture.addListener(Runnable {
cameraProvider = cameraProviderFuture.get()//获取相机信息
//预览配置
preview = Preview.Builder()
.build()
.also {
it.setSurfaceProvider(viewFinder.createSurfaceProvider())
}
imageCamera = ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build()
videoCapture = VideoCapture.Builder()//录像用例配置
// .setTargetAspectRatio(AspectRatio.RATIO_16_9) //设置高宽比
// .setTargetRotation(viewFinder.display.rotation)//设置旋转角度
// .setAudioRecordSource(AudioSource.MIC)//设置音频源麦克风
.build()
try {
cameraProvider?.unbindAll()//先解绑所有用例
camera = cameraProvider?.bindToLifecycle(
this,
cameraSelector,
preview,
imageCamera,
videoCapture
)//绑定用例
} catch (exc: Exception) {
Log.e(TAG, "Use case binding failed", exc)
}
}, ContextCompat.getMainExecutor(this))
}
3.2、录像方法：takeVideo()
/**
* 开始录像
*/
@SuppressLint("RestrictedApi", "ClickableViewAccessibility")
private fun takeVideo() {
val mDateFormat = SimpleDateFormat(FILENAME_FORMAT, Locale.US)
//视频保存路径
val file = File(FileUtils.getVideoName(), mDateFormat.format(Date()) + ".mp4")
//开始录像
videoCapture?.startRecording(
file,
Executors.newSingleThreadExecutor(),
object : OnVideoSavedCallback {
override fun onVideoSaved(@NonNull file: File) {
//保存视频成功回调，会在停止录制时被调用
ToastUtils.shortToast(" 录像成功 $file.absolutePath")
}
override fun onError(videoCaptureError: Int, message: String, cause: Throwable?) {
//保存失败的回调，可能在开始或结束录制时被调用
Log.e("", "onError: $message")
ToastUtils.shortToast(" 录像失败 $message")
}
})
btnVideo.setOnClickListener {
videoCapture?.stopRecording()//停止录制
//preview?.clear()//清除预览
btnVideo.text = "Start Video"
btnVideo.setOnClickListener {
btnVideo.text = "Stop Video"
takeVideo()
}
Log.d("path", file.path)
}
}
3.3、切换前后置摄像头方法:
3.4、完整代码如下：
package com.example.cameraxapp
import android.Manifest
import android.annotation.SuppressLint
import android.content.pm.PackageManager
import android.net.Uri
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import androidx.annotation.NonNull
import androidx.appcompat.app.AppCompatActivity
import androidx.camera.core.*
import androidx.camera.core.VideoCapture.OnVideoSavedCallback
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import com.example.cameraxapp.utils.FileUtils
import com.example.cameraxapp.utils.ToastUtils
import kotlinx.android.synthetic.main.activity_main.*
import java.io.File
import java.text.SimpleDateFormat
import java.util.*
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
class MainActivity : AppCompatActivity() {
private var imageCamera: ImageCapture? = null
private lateinit var cameraExecutor: ExecutorService
var videoCapture: VideoCapture? = null//录像用例
var cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA//当前相机
var preview: Preview? = null//预览对象
var cameraProvider: ProcessCameraProvider? = null//相机信息
var camera: Camera? = null//相机对象
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initPermission()
}
private fun initPermission() {
if (allPermissionsGranted()) {
// ImageCapture
startCamera()
} else {
ActivityCompat.requestPermissions(
this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS
)
}
btnCameraCapture.setOnClickListener {
takePhoto()
}
btnVideo.setOnClickListener {
btnVideo.text = "Stop Video"
takeVideo()
}
btnSwitch.setOnClickListener {
cameraSelector = if (cameraSelector == CameraSelector.DEFAULT_BACK_CAMERA) {
CameraSelector.DEFAULT_FRONT_CAMERA
} else {
CameraSelector.DEFAULT_BACK_CAMERA
}
startCamera()
}
}
private fun takePhoto() {
val imageCapture = imageCamera ?: return
val mDateFormat = SimpleDateFormat("yyyyMMddHHmmss", Locale.US)
val file =
File(FileUtils.getImageFileName(), mDateFormat.format(Date()).toString() + ".jpg")
val outputOptions = ImageCapture.OutputFileOptions.Builder(file).build()
imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this),
object : ImageCapture.OnImageSavedCallback {
override fun onError(exc: ImageCaptureException) {
Log.e(TAG, "Photo capture failed: ${exc.message}", exc)
ToastUtils.shortToast(" 拍照失败 ${exc.message}")
}
override fun onImageSaved(output: ImageCapture.OutputFileResults) {
val savedUri = Uri.fromFile(file)
val msg = "Photo capture succeeded: $savedUri"
ToastUtils.shortToast(" 拍照成功 $savedUri")
Log.d(TAG, msg)
}
})
}
/**
* 开始录像
*/
@SuppressLint("RestrictedApi", "ClickableViewAccessibility")
private fun takeVideo() {
val mDateFormat = SimpleDateFormat(FILENAME_FORMAT, Locale.US)
//视频保存路径
val file = File(FileUtils.getVideoName(), mDateFormat.format(Date()) + ".mp4")
//开始录像
videoCapture?.startRecording(
file,
Executors.newSingleThreadExecutor(),
object : OnVideoSavedCallback {
override fun onVideoSaved(@NonNull file: File) {
//保存视频成功回调，会在停止录制时被调用
ToastUtils.shortToast(" 录像成功 $file.absolutePath")
}
override fun onError(videoCaptureError: Int, message: String, cause: Throwable?) {
//保存失败的回调，可能在开始或结束录制时被调用
Log.e("", "onError: $message")
ToastUtils.shortToast(" 录像失败 $message")
}
})
btnVideo.setOnClickListener {
videoCapture?.stopRecording()//停止录制
//preview?.clear()//清除预览
btnVideo.text = "Start Video"
btnVideo.setOnClickListener {
btnVideo.text = "Stop Video"
takeVideo()
}
Log.d("path", file.path)
}
}
/**
* 开始拍照
*/
private fun startCamera() {
cameraExecutor = Executors.newSingleThreadExecutor()
val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
cameraProviderFuture.addListener(Runnable {
cameraProvider = cameraProviderFuture.get()//获取相机信息
//预览配置
preview = Preview.Builder()
.build()
.also {
it.setSurfaceProvider(viewFinder.createSurfaceProvider())
}
imageCamera = ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build()
videoCapture = VideoCapture.Builder()//录像用例配置
// .setTargetAspectRatio(AspectRatio.RATIO_16_9) //设置高宽比
// .setTargetRotation(viewFinder.display.rotation)//设置旋转角度
// .setAudioRecordSource(AudioSource.MIC)//设置音频源麦克风
.build()
try {
cameraProvider?.unbindAll()//先解绑所有用例
camera = cameraProvider?.bindToLifecycle(
this,
cameraSelector,
preview,
imageCamera,
videoCapture
)//绑定用例
} catch (exc: Exception) {
Log.e(TAG, "Use case binding failed", exc)
}
}, ContextCompat.getMainExecutor(this))
}
override fun onRequestPermissionsResult(
requestCode: Int, permissions: Array<String>, grantResults:
IntArray
) {
if (requestCode == REQUEST_CODE_PERMISSIONS) {
if (allPermissionsGranted()) {
startCamera()
} else {
Toast.makeText(
this,
"Permissions not granted by the user.",
Toast.LENGTH_SHORT
).show()
finish()
}
}
}
private fun allPermissionsGranted() = REQUIRED_PERMISSIONS.all {
ContextCompat.checkSelfPermission(baseContext, it) == PackageManager.PERMISSION_GRANTED
}
override fun onDestroy() {
super.onDestroy()
cameraExecutor.shutdown()
}
companion object {
private const val TAG = "CameraXBasic"
private const val FILENAME_FORMAT = "yyyy-MM-dd-HH-mm-ss-SSS"
private const val REQUEST_CODE_PERMISSIONS = 10
private val REQUIRED_PERMISSIONS = arrayOf(
Manifest.permission.CAMERA,
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.RECORD_AUDIO
)
}
}
4.项目封装的文件工具类：
/**
* @auth: njb
* @date: 2021/10/20 17:47
* @desc: 文件工具类
*/
object FileUtils {
/**
* 获取视频文件路径
*/
fun getVideoName(): String {
val videoPath = Environment.getExternalStorageDirectory().toString() + "/CameraX"
val dir = File(videoPath)
if (!dir.exists() && !dir.mkdirs()) {
ToastUtils.shortToast("Trip")
}
return videoPath
}
/**
* 获取图片文件路径
*/
fun getImageFileName(): String {
val imagePath = Environment.getExternalStorageDirectory().toString() + "/images"
val dir = File(imagePath)
if (!dir.exists() && !dir.mkdirs()) {
ToastUtils.shortToast("Trip")
}
return imagePath
}
}
5.项目的ToastUtils工具类代码：
package com.example.cameraxapp.utils;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.Gravity;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.StringRes;
import com.example.cameraxapp.app.MyApp;
import org.jetbrains.annotations.NotNull;
import java.lang.reflect.Field;
/**
* toast工具类
*/
public final class ToastUtils {
private static final String TAG = "ToastUtil";
private static Toast mToast;
private static Field sField_TN;
private static Field sField_TN_Handler;
private static boolean sIsHookFieldInit = false;
private static final String FIELD_NAME_TN = "mTN";
private static final String FIELD_NAME_HANDLER = "mHandler";
private static void showToast(final Context context, final CharSequence text,
final int duration, final boolean isShowCenterFlag) {
ToastRunnable toastRunnable = new ToastRunnable(context, text, duration, isShowCenterFlag);
if (context instanceof Activity) {
final Activity activity = (Activity) context;
if (!activity.isFinishing()) {
activity.runOnUiThread(toastRunnable);
}
} else {
Handler handler = new Handler(context.getMainLooper());
handler.post(toastRunnable);
}
}
public static void shortToast(Context context, CharSequence text) {
showToast(context, text, Toast.LENGTH_SHORT, false);
}
public static void longToast(Context context, CharSequence text) {
showToast(context, text, Toast.LENGTH_LONG, false);
}
public static void shortToast(String msg) {
showToast(MyApp.getInstance(), msg, Toast.LENGTH_SHORT, false);
}
public static void shortToast(@StringRes int resId) {
showToast(MyApp.getInstance(), MyApp.getInstance().getText(resId),
Toast.LENGTH_SHORT, false);
}
public static void centerShortToast(@NonNull String msg) {
showToast(MyApp.getInstance(), msg, Toast.LENGTH_SHORT, true);
}
public static void centerShortToast(@StringRes int resId) {
showToast(MyApp.getInstance(), MyApp.getInstance().getText(resId),
Toast.LENGTH_SHORT, true);
}
public static void cancelToast() {
Looper looper = Looper.getMainLooper();
if (looper.getThread() == Thread.currentThread()) {
mToast.cancel();
} else {
new Handler(looper).post(() -> mToast.cancel());
}
}
private static void hookToast(Toast toast) {
try {
if (!sIsHookFieldInit) {
sField_TN = Toast.class.getDeclaredField(FIELD_NAME_TN);
sField_TN.setAccessible(true);
sField_TN_Handler = sField_TN.getType().getDeclaredField(FIELD_NAME_HANDLER);
sField_TN_Handler.setAccessible(true);
sIsHookFieldInit = true;
}
Object tn = sField_TN.get(toast);
Handler originHandler = (Handler) sField_TN_Handler.get(tn);
sField_TN_Handler.set(tn, new SafelyHandlerWrapper(originHandler));
} catch (Exception e) {
Log.e(TAG, "Hook toast exception=" + e);
}
}
private static class ToastRunnable implements Runnable {
private Context context;
private CharSequence text;
private int duration;
private boolean isShowCenter;
public ToastRunnable(Context context, CharSequence text, int duration, boolean isShowCenter) {
this.context = context;
this.text = text;
this.duration = duration;
this.isShowCenter = isShowCenter;
}
@Override
@SuppressLint("ShowToast")
public void run() {
if (mToast == null) {
mToast = Toast.makeText(context, text, duration);
} else {
mToast.setText(text);
if (isShowCenter) {
mToast.setGravity(Gravity.CENTER, 0, 0);
}
mToast.setDuration(duration);
}
hookToast(mToast);
mToast.show();
}
}
private static class SafelyHandlerWrapper extends Handler {
private Handler originHandler;
public SafelyHandlerWrapper(Handler originHandler) {
this.originHandler = originHandler;
}
@Override
public void dispatchMessage(@NotNull Message msg) {
try {
super.dispatchMessage(msg);
} catch (Exception e) {
Log.e(TAG, "Catch system toast exception:" + e);
}
}
@Override
public void handleMessage(@NotNull Message msg) {
if (originHandler != null) {
originHandler.handleMessage(msg);
}
}
}
}
6.项目的Manifest代码如下：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.cameraxapp">
<uses-feature android:name="android.hardware.camera.any" />
<uses-permission android:name="android.permission.CAMERA"/>
<!--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" />
<application
android:name=".app.MyApp"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:requestLegacyExternalStorage="true"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true"
tools:replace="android:authorities">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
</provider>
</application>
</manifest>
7.运行效果如下图：可以看到拍照、录像，切换摄像头都是正常的
四、遇到的问题如下：
1.拍照成功但后台打印日志图片文件写入失败。
2.在Android 10及以上系统提示读写文件失败。
3.录像后屏幕黑屏，预览失败。
五、解决方法如下：
1.拍照成功，图片文件写入失败，根据以前项目的经验没有配置FileProvider。
2.在项目的res目录下配置file_paths
file_paths代码如下:
3.在manifest配置FileProvider，代码如下：
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true"
tools:replace="android:authorities">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
</provider>
4.Android10读写文件权限适配如下：
在AndroidManifest的application中设置android:requestLegacyExternalStorage="true"。
5.解决录像后屏幕黑屏，预览失败的方法：由于我在录像成功后主动调用了清除预览的方法，所以导致黑屏，预览失败，注销此方法即可。
6.以上就是今天的CameraXApi的使用，测试了小米、华为、三星、google、oppo、vivo等几款主流机型，Android 9、Android 10的系统，后面有机型会适配Android 11，主逻辑全部使用的是kotlin,实现了预览、拍照、录像、切换前后置摄像头等功能，当然本文没有仔细展开讲解和Camera1、Camera2的区别，因为这块内容很多，所以后面有时间整理一下，本文还有很多不足之处，望大家谅解，有问题及时提出，共同学习进步。
最后，项目的源码如下：
