BarcodeScanning.getClient()空指针异常问题求助

运行条码扫描功能时程序崩溃，抛出如下NullPointerException错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.mlkit.vision.barcode.internal.BarcodeScannerImpl com.google.mlkit.vision.barcode.internal.zze.zzb(com.google.mlkit.vision.barcode.BarcodeScannerOptions)' on a null object reference
                                                                                                    at com.google.mlkit.vision.barcode.BarcodeScanning.getClient(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.1.0:3)
                                                                                                    at pk.caltex.chevron.ScannerActivity.bindAnalyseUseCase(ScannerActivity.kt:180)
                                                                                                    at pk.caltex.chevron.ScannerActivity.bindCameraUseCases(ScannerActivity.kt:128)
                                                                                                    at pk.caltex.chevron.ScannerActivity.access$bindCameraUseCases(ScannerActivity.kt:45)
                                                                                                    at pk.caltex.chevron.ScannerActivity$setupCamera$1.invoke(ScannerActivity.kt:115)
                                                                                                    at pk.caltex.chevron.ScannerActivity$setupCamera$1.invoke(ScannerActivity.kt:112)
                                                                                                    at pk.caltex.chevron.ScannerActivity.setupCamera$lambda$0(ScannerActivity.kt:112)
                                                                                                    at pk.caltex.chevron.ScannerActivity.$r8$lambda$888cEQUj2f0zqrTZxCdbhbRUXAM(Unknown Source:0)
                                                                                                    at pk.caltex.chevron.ScannerActivity$$ExternalSyntheticLambda1.onChanged(Unknown Source:2)
                                                                                                    at androidx.lifecycle.LiveData.considerNotify(LiveData.java:133)
                                                                                                    at androidx.lifecycle.LiveData.dispatchingValue(LiveData.java:151)
                                                                                                    at androidx.lifecycle.LiveData.setValue(LiveData.java:309)
                                                                                                    at androidx.lifecycle.MutableLiveData.setValue(MutableLiveData.java:50)
                                                                                                    at pk.caltex.chevron.CameraXViewModel._get_processCameraProvider_$lambda$0(CameraXViewModel.kt:24)
                                                                                                    at pk.caltex.chevron.CameraXViewModel.$r8$lambda$f983IYe2OCbdRYR-WixR3PHO3jU(Unknown Source:0)
                                                                                                    at pk.caltex.chevron.CameraXViewModel$$ExternalSyntheticLambda0.run(Unknown Source:4)
                                                                                                    at android.os.Handler.handleCallback(Handler.java:873)
                                                                                                    at android.os.Handler.dispatchMessage(Handler.java:99)
                                                                                                    at android.os.Looper.loop(Looper.java:226)
                                                                                                    at android.app.ActivityThread.main(ActivityThread.java:7191)
                                                                                                    at java.lang.reflect.Method.invoke(Native Method)
                                                                                                    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:499)
                                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:942)

已尝试升级、降级所有库，独立示例程序可正常运行，也查阅了Google问题追踪器等相关资源。

排查方向 #

• 检查初始化时机：确保调用BarcodeScanning.getClient()前，ML Kit内部组件已完成初始化。错误栈显示调用发生在LiveData的onChanged回调中，需确认此时ML Kit的初始化流程是否已完成，避免过早触发扫描客户端创建。
• 核对依赖配置：对比示例项目的依赖清单，确认play-services-mlkit-barcode-scanning及相关基础库是否完整引入，无版本冲突或遗漏。
• 检查混淆规则：若项目开启混淆，需确保ML Kit内部类（如com.google.mlkit.vision.barcode.internal.zze）未被混淆，可在proguard-rules.pro中添加保留规则：

  -keep class com.google.mlkit.vision.barcode.internal.** { *; }
  

• 清理构建缓存：执行./gradlew clean后重新构建项目，排除缓存导致的依赖加载异常。
• 对比项目配置：将当前项目的模块级build.gradle、AndroidManifest.xml与示例项目逐一对比，排查权限声明、CameraX配置、ML Kit初始化流程的差异。

内容的提问来源于stack exchange，提问作者Hasnain