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jni调用java方法,该方法将自定义java接口作为参数

更新时间:2023-12-04 08:10:58

首先你需要构建一个可以在TagCallback兼容基类中包装本机C ++函数指针的类:

Well firstly you'll need to build a class that can wrap the native C++ function pointer in a TagCallback compatible base class:

public class NativeTagCallback : TagCallback
{
    protected long      cppCallbackPtr;

    public NativeTagCallback( long callbackPtr )
    {
        cppCallbackPtr = callbackPtr;
    }

    public native void NativeCallback( long callbackPtr, int arg0, String arg1, Set<String> arg2 );

    public void callback(int arg0, String arg1, Set<String> arg2) 
    {
        NativeCallback( cppCallbackPtr, arg0, arg2, arg2 );
    }
}

本机代码定义如下:

extern "C" jvoid Java_com_wrapper_NativeTagCallback_NativeCallback( JNIEnv* pEnv, jobject jCaller, jlong cppCallbackPtr, jint arg0, jstring arg1, jobject arg2 )
{
    MyCallback cppCallback = (MyCallback)cppCallbackPtr;
    const char* pCString = pEnv->GetStringUTFChars( arg1, 0);
    string arg1Str( pCString );
    pEnv->ReleaseStringUTFChars( arg1, pCString );

    set< string > arg2Set = ConvertJavaSetToCPPSet( arg2 );  // Perform your java to CPP set conversion here.

    cppCallbackPtr( (int)arg0, arg1Str, arg2Set );
}

然后你将创建相关的类并将其从C ++传递给你的函数as如下:

Then you would create the relevant class and pass it to your function from C++ as follows:

void MyCpp::setTags(set<string> tags, MyCallback callback)
{
    extern __thread JNIEnv* gpEnv;

    // Get the setTags function.
    jclass      jWrapperClass                   = gpEnv->FindClass( "com/wrapper/cocoswrapper" ); // Insert the correct class name here.    
    jmethodID   jWrapperSetTag                  = gpEnv->GetStaticMethodID( jWrapperClass, "setTags", "(Landroid/content/Context;Ljava/util/Set;Lcom/wrapper/TagCallback)V;" );

    // Get the TagCallback related function
    jclass      jNativeTagCallbackClass         = gpEnv->FindClass( "com/wrapper/NativeTagCallback" );
    jclass      jNativeTagCallbackConstructor   = gpEnv->GetMethodID( jNativeTagCallbackClass, "<init>", "(J)V" );
    jobject     jNativeTagCallbackObject        = gpEnv->NewObject( jNativeTagCallbackClass, jNativeTagCallbackConstructor, (jlong)callback)

    // Make function call.
    gpEnv->CallStaticVoidMethod( jWrapperClass, jWrapperSetTag, jAndroidContext, tags.GetJNIObject(), jNativeTagCallbackObject );
}