For the future generations of humanity:

QJniObject toast = QJniObject::callStaticObjectMethod( "android/widget/Toast", "makeText", "(Landroid/content/Context;Ljava/lang/CharSequence;I)" "Landroid/widget/Toast;", QNativeInterface::QAndroidApplication::context(), displayText.object<jstring>(), timeout ); if (toast.isValid()) { qDebug() << "Toast is valid"; toast.callMethod<void>("show"); } else { qDebug() << "Toast JNI object not valid"; }