Qml context object is null on app shutdown

Question

This is my code. I get those errors in the console every time I quit the application. Properties work just fine during execution, but I get this annoying warning every time.

qrc:/search.qml:17: TypeError: Cannot read property 'isConnected' of null
qrc:/search.qml:18: TypeError: Cannot read property 'scanStatus' of null
qrc:/search.qml:19: TypeError: Cannot read property 'device' of null

#main.cpp

Utility u;
view->rootContext()->setContextProperty("utility", &u);

#search.qml

property bool connected : utility.isConnected
property bool scanRunning : utility.scanStatus
property var searchedDevice : utility.device

Answer 1

Make sure your Utility object is not destroyed after your QML engine: create it before the engine if both are created on the stack. No need to check if utility is null with this solution.

Answer 2

You have to verify that utility is not null:

property bool connected : utility ? utility.isConnected : false
property bool scanRunning : utility ? utility.scanStatus : false
property var searchedDevice : utility ? utility.device : null