问在qml中单击两次后退按钮退出应用程序？

EN

Keys.onBackPressed: {
    timer.pressBack()
}
Timer{
    id: timer
    
    property bool backPressed: false
    repeat: false
    interval: 200//ms
    onTriggered: backPressed = false
    function pressBack(){
        if(backPressed){
            timer.stop()
            backPressed = false
            // leave application
            // your code
            leaveApp()
        }
        else{
            backPressed = true
            timer.start()
        }
    }
}