Error:Execution failed for task ':app:buildNative'. ＆ gt; A problem occurred'x/x/x/'NDK build' error resolution

The background of the story is like this   The function of the project to scan the license plate number , I found one on the Internet demo（ There are N Much of the .so and ram、x86、.h 、.cpp、.mk And so on ）, Import android studio This error is reported when running ,  Then go and see yourself ndk route    That's right! , And then over the wall googole After reading the relevant 66 Bar result   It's still useless .

Finally, I had no choice but to see Local my ndk-build This thing , Two files with similar names were found ,  One is

ndk-build.cmd

The other is

ndk-build

and Stack Overflow There is a very good answer on it   as follows ：

It seems to distinguish , If it is windows The system will use tape .cmd Suffixed files run （ Don't android studio Can't you distinguish yourself ？ doubt ....）;

Finally, I put my own project build.gradle The file is changed to this    as follows ：

task buildNative(type: Exec, description: 'Compile JNI source via NDK') {
    def ndkDir = android.ndkDirectory
    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
        commandLine "$ndkDir/ndk-build.cmd",
                '-C', file('src/main/jni').absolutePath, // Change src/main/jni the relative path to your jni source
                '-j', Runtime.runtime.availableProcessors(),
                'all',
                'NDK_DEBUG=0'
    } else {
        commandLine "$ndkDir/ndk-build",
                '-C', file('src/main/jni').absolutePath, // Change src/main/jni the relative path to your jni source
                '-j', Runtime.runtime.availableProcessors(),
                'all',
                'NDK_DEBUG=0'
    }

}

Pay attention to is if Inside Os You need to import a class ：

import org.apache.tools.ant.taskdefs.condition.Os

This is written in build.gradle Just the first few lines of the file ...

And then   compile 、 function    2 Minutes later   ok   No more mistakes    Problem solving ！