带有示例的UVCCamera，如何在Android Studio中导入？

Question

我想使用 USB 摄像头（UVC）在 Android Studio（Windows）中工作。我在使用 USB 摄像头库“ libuvccamera”时遇到了问题。我想知道如何解决这些问题或者获取另一种在应用程序中查看 USB 摄像头的方法。让我更好地解释一下发生了什么：

我使用 CameraFi 应用程序（https://www.camerafi.com/apps/）测试了 USB 摄像头，并且 Android 系统可以识别它（并正常工作）。

在搜索如何在 Android Studio 中使用 UVC（USB）摄像头后，我发现可以使用此库：https://github.com/saki4510t/UVCCamera。

下载此库+示例后，我尝试使用 Android Studio 打开（只需打开 builg.gradle），代码看起来不错，但是当我尝试运行 usbCameraTest0（或任何其他示例）时，构建失败，错误信息如下：

FAILURE: Build failed with an exception.

What went wrong: Execution failed for task ':libuvccamera:ndkBuild'. A problem occurred starting process 'command 'null/ndk-build.cmd''

尝试： 使用 --stacktrace 选项运行以获取堆栈跟踪。使用 --info 或 --debug 选项获取更多日志输出。使用 --scan 获取完整的洞察力。 获取更多帮助：https://help.gradle.org

BUILD FAILED in 2s 14 actionable tasks: 7 executed, 7 up-to-date => 如果使用 --stacktrace 选项运行，则会显示：

FAILURE: Build failed with an exception.

What went wrong: Execution failed for task ':libuvccamera:ndkBuild'. A problem occurred starting process 'command 'null/ndk-build.cmd''

异常信息为： org.gradle.api.tasks.TaskExecutionException: 任务执行失败，具体为：':libuvccamera:ndkBuild'。 at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:166) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:163) at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:191) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:156) at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62) at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108) at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67) at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46) at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:94) at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46) at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:95) at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57) at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56) at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:77) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52) at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416) at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406) at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165) at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250) at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158) at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102) at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52) at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:43) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:355) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:343) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:336) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:322) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:134) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:129) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:202) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:193) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:129) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64) at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48) at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56) 产生该异常的原因是： org.gradle.process.internal.ExecException: 启动进程 'command 'null/ndk-build.cmd'' 失败。 at org.gradle.process.internal.DefaultExecHandle.execExceptionFor(DefaultExecHandle.java:237) at org.gradle.process.internal.DefaultExecHandle.setEndStateInfo(DefaultExecHandle.java:214) at org.gradle.process.internal.DefaultExecHandle.failed(DefaultExecHandle.java:364) at org.gradle.process.internal.ExecHandleRunner.run(ExecHandleRunner.java:87) at org.gradle.internal.operations.CurrentBuildOperationPreservingRunnable.run(CurrentBuildOperationPreservingRunnable.java:42) ... 3 more net.rubygrapefruit.platform.NativeException: 无法启动 'null/ndk-build.cmd'。 at net.rubygrapefruit.platform.internal.DefaultProcessLauncher.start(DefaultProcessLauncher.java:27) at net.rubygrapefruit.platform.internal.WindowsProcessLauncher.start(WindowsProcessLauncher.java:22) at net.rubygrapefruit.platform.internal.WrapperProcessLauncher.start(WrapperProcessLauncher.java:36) at org.gradle.process.internal.ExecHandleRunner.startProcess(ExecHandleRunner.java:98) at org.gradle.process.internal.ExecHandleRunner.run(ExecHandleRunner.java:71) ... 4 more java.io.IOException: 在目录

• 在https://help.gradle.org获取更多帮助

构建失败，用时2秒。16项任务中有3项已完成，13项是最新的。

- Ana

Answer 1

我曾经遇到过同样的问题。我在local.properties文件中添加了SDK和NDK路径。这是自述文件指令中的第5步。

sdk.dir=/home/username/Android/Sdk
ndk.dir=/home/username/Android/Sdk/ndk-bundle

我正在使用Ubuntu 16.04，Windows路径不同。

希望这可以帮到你。谢谢。

- jeranio

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这个解决方案不起作用。请给我建议另一个解决方案。 - Abhijit Rajmane

启动进程时出现问题，命令为'null/ndk-build.cmd'。这告诉我NDK路径未设置。 - jeranio

Answer 2

设置此路径

sdk.dir=/home/username/Android/Sdk ndk.dir=/home/username/Android/Sdk/ndk-bundle

取消注释

NDK_TOOLCHAIN_VERSION := 4.9

under UVCCamera\libuvccamera\src\main\jni\Application.mk

- Mahicodex

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目前你的回答不够清晰。请编辑并添加更多细节，以帮助其他人理解它如何回答所提出的问题。你可以在帮助中心找到有关如何撰写好答案的更多信息。 - Community

Answer 3

看起来有点老了，但在我的情况下，在Android Studio（Windows）上使用3.3.3版本构建会失败，并出现与您相同的错误。

在更改local.properties文件后：

    # header note.
    #Fri Mar 31 14:42:53 HOVT 2023
    sdk.dir=D\:\\Programs\\AndroidSDK

到

    # header note.
    #Fri Mar 31 14:42:53 HOVT 2023
    sdk.dir=D\:\\Programs\\AndroidSDK
    ndk.dir=D\:\\Programs\\AndroidSDK\\ndk\\21.4.7075529

修复了问题，我现在可以运行应用程序。

注意：

1. 更正路径并检查文件夹AndroidSDK\\ndk中的NDK版本

2. 您不必在\libuvc\src\main\jni\Application.mk中注释# NDK_TOOLCHAIN_VERSION := 4.9，因为在此版本中已经注释掉了

- Cemn1