Hello,
Have you cloned and copied the toolkit repo? Once you have a copy of the toolkit on your machine you need to do the following (example for a C++ application, QML follows a similar pattern):
1. Include the toolkit in .Pro
# path of the toolkit relative to the sample
TOOLKIT_PRI_PATH = $$PWD/../../../arcgis-runtime-toolkit-qt
exists($$TOOLKIT_PRI_PATH/uitools/toolkitqml.pri) {
include($$TOOLKIT_PRI_PATH/uitools/toolkitcpp.pri)
} else {
error(TOOLKIT_PRI_PATH is missing which is required to build this application.)
}
2. Include toolkit in main.cpp
#include "Esri/ArcGISRuntime/Toolkit/register.h"
3. Register the component in main
Esri::ArcGISRuntime::Toolkit::registerComponents(*(view.engine()));