Back button functionality and multiple times statement execution in Component.onCompleted

Rambo

Hi,
I am developing an app which is for now mainly for Android. There are 1-2 points that I want to discuss, which are as follows:

Back button functionality in app

For this I have searched and tried many things I have like two main screen in app containing sub components in it. When I am trying to switch from second screen to first screen using Keys.onReleased button click handler on second screen, it is actually not going inside handler. Here is code snippet
@Item {
id: student_home_page;
focus: true

// ///////////////////////////////////////////////////////////////

Keys.onReleased: {
console.log("TEST for Back ");
if (event.key == Qt.Key_Back) {
console.log("BAck Button HAndled");
event.accepted = true;
}
}
}@

So could anyone guide me what I am doing wrong I tried to override onBackPressed in android too but did not work.

Sometimes when I push or pop between two pages the statements in Component.onCompleted executes more then once usually three times. This is causing serious performance issues as I am processing some json strings there. So I research about it and found something but I need to resolved for sure. so Any suggestions on this too.

searched link that I found "Fast Forwarding ":http://qt-project.org/doc/qt-4.8/qdeclarativestates.html#state-fast-forwarding

Thanks in adavnce