Here's explanation of my method

Add this line in desktop file

MimeType=x-maemo-urischeme/randomName;

Now suppose a url, randomName:helloWorld is called, ur app in exec will be called with helloWorld as argument.

you can enter the url in browser and check, or use Qt.openUrlExternally method from qml also.
Also feeditems url, if set similarly, will invoke ur app