Flexible Height Gallery - a Better Way

[Anonymous]

 So the flexible height gallery control is very limited in usefulness out of the box.  The only controls with "auto height", which this functionality relies on, is the label control and HTML Text control.

I've seen some examples where people have used the Label control (making the text invisible) as a way to dynamically size each row (by adding more text in it), however, this was a bit quirky for me.  And now way to use this to really specify the height of the individual gallery item at a pixel level.

So I got to thinking that if the HTML Text control also works with Auto Size (it does), perhaps one could use this by using HTML to create a variable sized (to the pixel) vertical line.  

And yes, it works...  🙂  

Let's say your gallery is called Gallery1.  So what you would do is as follows:

1. In Gallery1 add a column to what you have in Items, that will represent the height you want for each individual row.  I'll call this MyHeight for now.  So if I have 3 rows and want the first to be 10 pixels high, the second 20, and the third 30, I would just add these to the table. 
   
   There are other ways to do this (ie: value of a control within the gallery itself - ie: a slider that would allow the user to dynamically change it, resizing each row on the flow) - however, this depends on your usage.   
   
   
2. Add an "HTML text" control to your gallery - I'll call this HtmlText1.  Set the following on HtmlText1:
   
   Auto height: ON  (IMPORTANT - and note I've seen PowerApps turn this off automatically sometimes, not sure why, so check it)
   X: 0
   Y: 0
   Width: 1
   Padding: Left: 0, Bottom: 0, Right: 0, Left: 0
   Height: Gallery1.TemplateHeight   (note: this could be any size you want to be the MINIMUM height, but setting it to this will allow you to drag the template size to this minimum)
   
   
3. Now the "magic" here is in the HtmlText setting, so set HtmlText1.HtmlText to:
   
   

   "<hr width=1' size='" & ThisItem.MyHeight & "'>"

   (notice the single and double quotes in the above).
   
   This will create HTML to draw a vertical line 1 pixel wide and "ThisItem.MyHeight" pixels high.  Since the HtmlText1 control has Auto height On, the size of HTML 1 will change based on the length of the line.
   
   Note: Even though we set padding to 0, it appears that PowerApps will still make the height of the HtmlText1 control to itself be 5 pixels more than the length of the line.  Probably is a way around this, but doesn't matter to me.  
   
   Also note that there are many ways to specify the height of the line.  If you wanted to do this in a Slider that is within the gallery (letting the user set the individual slider to the size of that row), you could (instead of ThisItem.MyHeight) use ThisItem.Slider1.Value * 10 or something.
   
   
4. And lastly, if you have a Separator line, say Separator1, you'd want to set its Y value to Max( HtmlText1.Height, Gallery1.TemplateHeight )

While this still is not a perfect substitute for the Gallery control not REALLY allowing for a flexible size (which it arguably SHOULD do) it does go a long way.  

Hope this helps someone.  If there is a better way to do this, please let me know, I'm very open to a better way.

[v-monli-msft]

Hi @Anonymous,

Thank you for sharing your resolution here and hope that this would benefit anyone who has the similar situation.

Regards,

Mona 

[Anonymous]

Thanks @v-monli-msft.  

BTW - I discovered today that this works differently when run in another "PowerApps Player" app - ie: "Windows Player" (the Windows store app), Android, and iOS vs the "Web Player" app that appears to be used when running from Studio or SharePoint.   

It appears that there are text and spacing issues when run across platforms.  I suspect that the way "pixels" are calculated within the HTML text control may vary between platforms.  I've seen similar things happen with text box placement, height etc between platforms, so believe this is related.

My workaround (as longer term this will need to work cross platform) will be to manually figure out a "scaling factor" for each player, and have the app apply that when its running (though there is no direct way to figure this out from PowerApps - I had to use an MS Flow that PowerApps calls and parse x-ms-user-agent to determine this from within my app).  If I get this part working in the near future, I'll update the post.  that said, I would suspect that this scaling might change in future versions of PowerApps as (hopefully) Microsoft brings the scaling across the different "players" closer together.  

[PytByt]

@Anonymous could you please add a demo sir? i need this...

thank you

[Anonymous · Accepted solution]

I'll try to post one for you.

Actually, with some of the changes in PowerApps, (there are still some issues with flexible height galleries), I had to change my approach, but what I've settled on seems to consistently work, regardless of the platform it was running on.  

With the other approach (posted above), I later discovered the sizing would be different depending on whether it was run as an app in Chrome/Chromium or Edge, whether it was running the web development environment, or if running on iOS or Android.  

I'm now using a rectangle object (either as a separator (height=1, Y=max height) or bounding rectangle (X=0, Y=0, height = max location of other controls) instead of the HTML.  This seems to work much better now.  I think the HTML approach differed between environments perhaps due to different assumptions those browsers/etc made about HTML spacing.  

To use the "bounding rectangle" approach, I set the X and Y of the rectangle to 0, and then for Height do something like the following:

Max( 
    If( 'FFG - CTRL TEXT INPUT'.Visible,         'FFG - CTRL TEXT INPUT'.Y         + 'FFG - CTRL TEXT INPUT'.Height,       0 ),
    If( 'FFG - CTRL DATE'.Visible,               'FFG - CTRL DATE'.Y               + 'FFG - CTRL DATE'.Height,             0 ),
    If( 'FFG - CTRL DATE RANGE START'.Visible,   'FFG - CTRL DATE RANGE START'.Y   + 'FFG - CTRL DATE RANGE START'.Height, 0 ),
    If( 'FFG - CTRL DROPDOWN'.Visible,           'FFG - CTRL DROPDOWN'.Y           + 'FFG - CTRL DROPDOWN'.Height,         0 ),
    If( 'FFG - CTRL COMBOBOX'.Visible,           'FFG - CTRL COMBOBOX'.Y           + 'FFG - CTRL COMBOBOX'.Height,         0 ), 
    If( 'FFG - CTRL CHECKBOX'.Visible,           'FFG - CTRL CHECKBOX'.Y           + 'FFG - CTRL CHECKBOX'.Height,         0 ),
    If( 'FFG - ERROR MSG Txt'.Visible,           'FFG - ERROR MSG Txt'.Y           + 'FFG - ERROR MSG Txt'.Height,         0 ),
    If( 'FFG - HEADER Txt'.Visible,              'FFG - HEADER Txt'.Y              + 'FFG - HEADER Txt'.Height,            0 ),
    If( 'FFG - textValue RESULT'.Visible,        'FFG - textValue RESULT'.Y        + 'FFG - textValue RESULT'.Height,      0 ), // Should only be visible if Debug is enabled
    /* Default */ 'FFG - NAME Txt'.Y + 'FFG - NAME Txt'.Height
) + 5

So in the above, my gallery is actually used to collect a user supplied range of filter criteria.  This is done in a custom control (FlexibleFilterGallery), I created, and the above is a snippet from it.  When using the control, it is passed in a table of "filter criteria" that specifies the type of control for the filter, the available values (for comboboxes, list boxes, drop downs), defaults, ranges (ie: start/end dates, numerical ranges, etc) that the control will use to provide the user the correct type of control, as well as limit options / validate user input.  

The template includes all those controls (combos, LBs, checkboxes, text entry, date, date range, etc), but only the one specified by the specific record in the table is set to Visible.

BTW - you'll also notice the check for the 'FFG - ERROR MSG Txt'.Visible.  This is only Visible if there was an error, and actually will increase the size of that cell to display the error message (ie: if for date range, end date is before start date) and once the error is corrected, the error message will then have Visible set to false, and thus the height of the cell will be reduced again automatically.

Thus, the code above with the If()s determine which one is visible, and then get its current Height - which depending on the control could be variable height (especially for text with autoheight set, etc).  

So this grabs the Max position from each of the Visible controls (in some other uses there might be multiple that are visible), adds 5 to this, and sets it to the height of the rectangle.  The flexible gallery control then correctly sizes itself, meaning that each record may be displayed in the gallery with a different height.

A slightly more complex way I use this is in a gallery or items (customer records) where each record may have multiple underlying records that I wish to display in the same template.  While I could do this with nested galleries (a gallery contained in a gallery), instead I'm using an HTML text field (with an HTML table) that is set to autoheight for the sub record.  (while this is not my specific use, consider this like a customer record, where perhaps the customer own multiple vehicles, so the "subrecord" is about the vehicles).  Initially the HTML is hidden, unless the user clicks on the "Show Details" button, which will then cause it to be set to Visible, and thus PowerApps will recalculate the size of that record in the template dynamically - expanding it as necessary.  You can show details of only the records you want which will only resize that one in the gallery accordingly.  Some have only 0, 1, or many subrecords (ie: vehicles in my example) - so the size will differ based on the record itself (number of rows as well as size of that row).  

Here I'm using the separator line approach (no difference in function, just visual appearance) with the HTML text set to autoheight.  So the Y for the separator (which is the bottom most control in the template) is:

If( 'AT - Usage Details Html_1'.Visible, 
    'AT - Usage Details Html_1'.Y + 'AT - Usage Details Html_1'.Height,
     'AT - Usage Details Html_1'.Y
)  + 5 

Works VERY well.  Sorry if the explanation was confusing - was typing this up between morning meetings (have to run for one).  Will see if I can post some screenshots later.

But hopefully the above gives you some ideas.

[jlucarelli]

Thank you!  That worked like a charm for me.  And now that I know you can embed control properties in the HTML text control, I imagine I'll find other users for that as well.  🙂