Global Variable Keeps Changing

[mcalistor]

I use a global variable as a size multiplier for most of my controls.  On each screen is a slider (scale of 50 to 100) that defaults to this value, and On Change, updates the value of the global variable to the Slider Value * 100.  This worked for a while, but recently, it started resetting to the minimum value of my sliders (50), but only on certain screens, shrinking all the controls down to their minimum size of 50%.  This makes it a little difficult to use on a mobile device.  So to workaround this bug, I started passing the current value of the size multiplier as a parameter to all the screens that were exhibiting the problem and using the passed parameter to reset the global variable to its proper value; but now, even simple actions like changing a dropdown menu seem to reset the global variable to .5.  If I navigate back, reset the slider to another value, and navigate to the suspect screen again, the global variable behaves like it should.

The issue doesn't manifest itself when I'm editing, only when using the published version.  Doesn't matter if it's on a phone, desktop, Android, IOS, the Windows App.  Seems to be a runtime bug.

BTW, this would be a whole lot easier if my app would auto scale between a small phone screen an HD monitor, but for now, it's the only way I can make the app usable on a desktop and mobile device. 

[Pranav_Shroti]

Hi,

I can relate to what you are saying. I have observed it myself, espically when using number type global variables, I get garbage values or some other values but not the one I am trying to set.

In my case it mostly happens when I am testing my app in edit mode. I found a workaround by closing the app, clearing the browser history then opening and publishing the app again. Plus I always run the app from All app list page --> Play.

Hope this helps,

Pranav

[mcalistor]

Maybe using an external data source, a collection, or even a persistent control be a workaround? Unfortunately, using an external data source means having to tie it each user, mucho overhead.

[Pranav_Shroti]

I have not personally tried this, however if you create a string global variable and then before using it convert it into number, perhaps that will do the trick.

Hope this helps,

Pranav

[mcalistor]

I was going to try to implement this, but then I realized how many hundreds of controls that are tied to this variable.  Can't imagine how long it would take to convert all the numbers from to/from text datatype.  Instead, going to remove the slider control from all screens but the home screen and see if that helps. 

[mcalistor · Accepted solution]

Update, I removed all slider controls that can modify the variable, except the one on the main screen, problem solved.  Apparently having too many controls that can modify a global variable is a problem.

[HEATFreight]

@mcalistor I'm noticing that a boolean value –which can get modified by several sliders and other buttons– is getting reset due to the OnChange property of one or more of the sliders!

It's been tough figuring out a boolean logic (or otherwise) which is capable of doing what I want. These are price sliders which change the thousandths or hundredths places in the dollar amounts of various inputs. These inputs are all in pairs where the bottom layer is a text input box and the top layer is a label controlled by the sliders. If the user clicks the label once, it becomes hidden, thus revealing the manual text input box. The user clicks this box and begins typing a price manually. Or they can use the sliders and the label will become visible again and automatically update as the slider is moved. Not only that, but another dollar amount input which depends on the first price input as well as another price input is calculated by taking the difference of the two. And this calculation can also be reversed, where the user would click the top layer (dollar value label) of the previously calculated value, thus hiding the label and unhiding the manual input. The user can then manually input that amount and cause the first value we mentioned to be calculated instead of manually typed or slider controlled.

And on top of all that, each of the three dollar values must also default to a value extracted from some JSON data within the record in question. Thus there are three options for how to arrive at a value to be displayed: A) use the value from the record, B) manually input a value with keyboard, or C) use sliders to set price without keyboard.

But because manipulating the sliders must trigger the logic of unhiding the top layer of the label-input pair (so that the slider value will update live in the label, which I could not figure out how to do with the input, thus the label-input pair), the first time the user navigates to that form after opening the app, the sliders initialize and that must trigger their OnChange property, and thus a boolean which needs to be TRUE is reset to FALSE.

I have wracked my brain trying to sort out how to achieve the flexible functionality I want without this annoying peculiarity. Not gonna be able to train users to close and reopen the record which they are editing in the event that the price is displayed wrong as a result of this slider-OnChange-wrong-boolean bug. They freak out and ask me why their prices aren't saving. And I tell them "Close and reopen it. Nothing has changed. Only the way it was displayed to you is wrong. The data you previously input was saved, and will be visible upon reopening the record."

So now that I know for sure it's the slider OnChange property tripping on first time that screen loads, I should be able to workaround, albeit with substantial changes to the logic. It's worth noting: I have the setting to delay calculating hidden fields enabled (Enhanced performance for hidden controls), meaning logic doesn't get evaluated until the underlying element is visible. I think maybe this causes the Slider.OnChange properties to trigger upon the first load of that particular screen.