android - 从ndk中的不同线程调用Java方法

Question

我正在尝试使用android的NDK从c++中的分离线程中调用java静态方法。

到目前为止，我已经:

    JNIEnv *env =AttachJava();

    jclass cls2 = env->FindClass("com/actvt/showdown/pluggin/Utils");  // try to find the class
    //jmethodID mid2 = env->GetStaticMethodID(cls2, "AddSound", "(Landroid/app/Activity;Ljava/lang/String;I)V");  // find method
    jmethodID mid = env->GetStaticMethodID(cls2, "addFrame", "(Landroid/app/Activity;JIIII)V");  // find method
    jclass dataClass = env->FindClass("android/app/Activity");
    jobject javaClassRef =  env->AllocObject(dataClass);
    env->CallStaticVoidMethod(cls2, mid,javaClassRef,(long)frame,0,footageIndex,frameNumber,width,height);

我将这个线程附加到jvm上，其名称为AttachJava wich:

 JNIEnv* Wrapper::AttachJava()
{
    JNIEnv* myNewEnv;
    JavaVMAttachArgs args;
    args.version = JNI_VERSION_1_6; // choose your JNI version
    args.name = nullptr; // you might want to give the java thread a name
    args.group = nullptr; // you might want to assign the java thread to a ThreadGroup
    Wrapper::jvm->AttachCurrentThread(&myNewEnv, &args);
    return myNewEnv;
}

而且我在运行时遇到以下错误:

06-14 10:04:31.548 32423-484/com.learnopengles.airhockey A/art: art/runtime/java_vm_ext.cc:470] JNI DETECTED ERROR IN APPLICATION: JNI GetStaticMethodID called with pending exception java.lang.ClassNotFoundException: Didn't find class "com.actvt.showdown.pluggin.Utils" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/system/lib, /vendor/lib, /system/lib, /vendor/lib]]
06-14 10:04:31.548 32423-484/com.learnopengles.airhockey A/art: art/runtime/java_vm_ext.cc:470]   at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:56)
06-14 10:04:31.548 32423-484/com.learnopengles.airhockey A/art: art/runtime/java_vm_ext.cc:470]   at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:380)
06-14 10:04:31.548 32423-484/com.learnopengles.airhockey A/art: art/runtime/java_vm_ext.cc:470]   at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)

如果您还有其他需要，我随时为您服务

问候，

Answer 1

解决我的问题的方法是，在启动线程之前，请在ndk调用开始时保留对我在不同线程中所需的所有类的引用，然后在这些线程中使用它们。我也可以将它们作为参数提供给线程。

找到了要去pskink并根据此文档:https://developer.android.com/training/articles/perf-jni.html#faq_FindClass