error: undefined reference to `ANativeWindow_fromSurface`

[SamuelYeh]

hello.
I am a beginner of Qt,
I was trying to use Qt to make an Android application and used GStreamer(not QtGStreamer) to stream video through RTSP.
But when I used

QPlatformNativeInterface *nativeInterface = QApplication::platformNativeInterface();
    jobject activity = (jobject)nativeInterface->nativeResourceForIntegration("QtActivity");
    QAndroidJniEnvironment * qjniEnv;
    JNIEnv * jniEnv;
    JavaVM * jvm = qjniEnv->javaVM();
    jvm->GetEnv(reinterpret_cast<void**>(&qjniEnv), JNI_VERSION_1_6);
    jvm->AttachCurrentThread(&jniEnv,NULL);

    jint r_id_content = QAndroidJniObject::getStaticField<jint>("android/R$id", "content");

    QAndroidJniObject view = ((QAndroidJniObject) activity).callObjectMethod("findViewById", "(I)Landroid/view/View;", r_id_content);
    if (view.isValid()) {
        QAndroidJniObject child1 = view.callObjectMethod("getChildAt", "(I)Landroid/view/View;", 0);
        QAndroidJniObject child2 = child1.callObjectMethod("getChildAt", "(I)Landroid/view/View;", 0);
        if (child2.isValid()) {
            QAndroidJniObject sHolder = child2.callObjectMethod("getHolder","()Landroid/view/SurfaceHolder;");
            if (sHolder.isValid()) {
                QAndroidJniObject theSurface = sHolder.callObjectMethod("getSurface","()Landroid/view/Surface;");
                if (theSurface.isValid()) {
                    ANativeWindow* awindow = ANativeWindow_fromSurface(jniEnv, theSurface.object());
                    qDebug() << "This is a ANativeWindow " << awindow;
                }
            }
        } else {
            qDebug() << "Views are not loaded yet or you are not in the Qt UI Thread";
        }
    }

to get the ANativeWindow,
It got an error: undefined reference to 'ANativeWindow_fromSurface'

I have added QT += androidextras in .pro and
#include<android/native_window.h>
#include<android/native_window_jni.h>
in .cpp file, I don't know what else should I do.

Is there anyone can help me to solve this problem?
Thanks.

[Ferni]

I found a similar java code vulkan post and I had no problem. After added the right includes everything worked fine.

[SamuelYeh]

Thanks for your reply,
but I thought that my problem occurred when linking the "android/native_window_jni.h" or something else.
Should I check my Android NDK?

[Ferni]

Hi @SamuelYeh , I didn't read your reply before. I think that you didn't add something like this in your .pro. I think that the error comes because you are not linking with libandroid.

LIBS += -L/opt/android-ndk-r12b/platforms/android-19/arch-arm/usr/lib -landroid