ndk 17.0.4找不到文件異常

Caused by: java.io.IOException: error=2, No such file or directory

本着嚐鮮的心態，最近把Android studio升級到了Android Studio 3.1.2，升級之後項目突然不能正常編譯運行了，報:

:app:transformNativeLibsWithStripDebugSymbolForDebug

Caused by: java.io.IOException: error=2, No such file or directory

詳細報錯信息：

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformNativeLibsWithStripDebugSymbolForDebug'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:63)
    at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:88)
    at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
    at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:124)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:80)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:105)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:99)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:625)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:580)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:99)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.gradle.process.internal.ExecException: A problem occurred starting process 'command '/Users/yang/Library/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64/bin/mips64el-linux-android-strip''
    at org.gradle.process.internal.DefaultExecHandle.execExceptionFor(DefaultExecHandle.java:220)
    at org.gradle.process.internal.DefaultExecHandle.setEndStateInfo(DefaultExecHandle.java:204)
    at org.gradle.process.internal.DefaultExecHandle.failed(DefaultExecHandle.java:340)
    at org.gradle.process.internal.ExecHandleRunner.run(ExecHandleRunner.java:86)
    at org.gradle.internal.operations.BuildOperationIdentifierPreservingRunnable.run(BuildOperationIdentifierPreservingRunnable.java:39)
    ... 6 more
Caused by: net.rubygrapefruit.platform.NativeException: Could not start '/Users/yang/Library/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64/bin/mips64el-linux-android-strip'
    at net.rubygrapefruit.platform.internal.DefaultProcessLauncher.start(DefaultProcessLauncher.java:27)
    at net.rubygrapefruit.platform.internal.WrapperProcessLauncher.start(WrapperProcessLauncher.java:36)
    at org.gradle.process.internal.ExecHandleRunner.run(ExecHandleRunner.java:68)
    ... 7 more
Caused by: java.io.IOException: Cannot run program "/Users/yang/Library/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64/bin/mips64el-linux-android-strip" (in directory "/Users/yang/AndroidStudioProjects/VPOS/app"): error=2, No such file or directory
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
    at net.rubygrapefruit.platform.internal.DefaultProcessLauncher.start(DefaultProcessLauncher.java:25)
    ... 9 more
Caused by: java.io.IOException: error=2, No such file or directory
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:247)
    at java.lang.ProcessImpl.start(ProcessImpl.java:134)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
    ... 10 more

問題分析：

看最後一段報錯信息：

Caused by: java.io.IOException: error=2, No such file or directory
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:247)
    at java.lang.ProcessImpl.start(ProcessImpl.java:134)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
    ... 10 more

java IO異常，找不到文件或者目錄。一般報這種問題，都是缺少文件。既然是缺少文件，那我們向上看，看看缺少哪些文件或者目錄，找到了這個路徑：

/Users/yang/Library/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64/bin/mips64el-linux-android-strip

我們根據這個路徑，去看看是不是真的缺少這個文件或者目錄：

/Users/yang/Library/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64/

上面這個目錄下缺少文件，只到了.../prebuilt/darwin-x86_64/這個層級，缺少.../prebuilt/darwin-x86_64/bin/mips64el-linux-android-strip

這個目錄是ndk預編譯的一種工具鏈，用來預編譯以mips CPU指令集的so文件。

我們看到Android SDK中ndk的版本爲17.0.4754217，最新的。我們猜測Google是在新版本的NDK中刪去了對mips指令集CPU預編譯的支持。

我們找一下老版本的NDK文件，看看該目錄下是不是有完整的mips工具鏈文件，從這裏下載老版本NDK文件： 
https://developer.android.com/ndk/downloads/older_releases

我們下載上一個版本16b，下載解壓後，到相同路徑下去看，文件都是齊全的：

至此我們找到了問題的原因，Google在新版本17.0.4754217的NDK中，刪去了對mips指令集CPU預編譯的支持，在預編譯具有mips的so文件的項目時，就會報缺少文件或者目錄的錯誤。

解決辦法：

第一種：

這種方法最簡單，在gradle文件中配置打包參數，打包時排除/mips64/和/mips/文件下的所有so文件。

android {

    ...

    packagingOptions {
        exclude 'lib/mips64/*.so'
        exclude 'lib/mips/*.so'
    }
}

第二種：

刪除/mips64/和/mips/文件下的所有so文件

第三種：

將SDK中的NDK回退到16b版本，去這裏下載16b版本的ndk文件 
https://developer.android.com/ndk/downloads/older_releases

解壓之後，替換掉原來SDK中的ndk-bundle文件，即.../Android/sdk/ndk-bundle/

或者將解壓後的.../prebuilt/darwin-x86_64/，複製過去，這樣17版本的ndk也具有了預編譯mips so文件的能力

參考：

https://stackoverflow.com/questions/50253566/after-using-android-studio-3-1-2-it-showing-error-2-no-such-file-or-directory

https://stackoverflow.com/questions/50300179/gradle-build-fails-following-update-of-android-studio-to-3-1-2