Google Analytics – How can I change or overwrite UTM parameters for a pageview?

We have implemented a chat support service on our website that connects users to various pages on our website. Links in this bot are provided with a UTM parameter to identify that the user has traversed the bot to get to other pages. The content of this bot is loaded into an iframe and therefore can not be easily changed.

When a user comes to this site, their UTM parameters are stored in a session variable to keep it for further page views. A user clicking a link in the chat bot may already have some of these UTM parameters.

When a user clicks on a link in this bot, he can then check if additional parameters are stored in that session variable and may attach or overwrite it before sending the pageview.

I've found this documentation that lets you set and push campaign variables through analytics.js. However, I fear that multiple page views will be recorded every time this happens.

Dart – Flutter – Error while using PageView & ListView

I'm trying to make a PageView, PageController, and ListView merry-go-round of these scrolling, horizontally scrollable maps with fluttering. But it triggered this exception …

══╡ EXCEPTION BY RENDERING LIBRARY ╞═════════════════════════════════════════ ═ ═══════════════
I / Flutter (17678): The following statement was raised during performResize ():
I / Flutter (17678): Horizontal viewport received an unrestricted height.
I / Flutter (17678): The viewports are expanded in the transverse axis to fill their container and restrict child element matching
I / flutter (17678): its extension in the transverse axis. In this case, an unlimited amount was assigned to a horizontal viewport
I / flutter (17678): vertical space in which to expand.

Can someone help me to fix the problem?

I want to put this merry-go-round in a background-filled wallpaper, transform the class, and hide the transition.

void initState () {
super.initState ();
Controller = PageController (
Start page: 0,
keepPage: true,

Create Widget (BuildContext Context) {

return AnimatedBuilder (
Builder: (BuildContext Context, widget child) {
back scaffold (
body: ListView (Children: [
new stack (
Children: [
new AspectRatio (...),
new transformation (...),
New ListView.builder (
itemCount: 3,
scrollDirection: Axis.horizontal,
Padding: EdgeInsets.symmetric (vertical: 16.0),
itemBuilder: (BuildContext context, int index) {
if (index% 3 == 0) {
return _buildCarousel (context, index ~ / 3);
} else {
return divider ();
Widget _buildCarousel (BuildContext Context, int carouselIndex) {
Return the column (
mainAxisSize: MainAxisSize.min,
Children: [
Text ("carousel $ carouselIndex"),
SizedBox (
// You can use an aspect ratio for tablet support here
Height: 200,0
child: PageView.builder (
// Save this controller in a state to save the scroll position of the carousel
Controller: PageController (viewportFraction: 0.8),
itemBuilder: (BuildContext Context, int itemIndex) {
return _buildCarouselItem (context, carouselIndex, itemIndex);
Widget _buildCarouselItem (
BuildContext context, int carouselIndex, int itemIndex) {
Return padding (
Padding: EdgeInsets.symmetric (horizontal: 4.0),
Child: Container (
Decoration: BoxDecoration (
Color: Colors.grey,
borderRadius: BorderRadius.all (Radius.circular (4.0)),

What is Google Pageview?