Titanium JIRA Archive
Titanium SDK/CLI (TIMOB)

[TIMOB-23215] Windows: Data binding: Using attribute in ListItem that is not in data crashes view

GitHub Issuen/a
TypeBug
PriorityHigh
StatusClosed
ResolutionDuplicate
Resolution Date2016-04-26T14:53:33.000+0000
Affected Version/sn/a
Fix Version/sn/a
ComponentsWindows
Labelswindows
ReporterRene Pot
AssigneeKota Iguchi
Created2016-04-14T16:07:46.000+0000
Updated2017-03-21T23:14:00.000+0000

Description

I have a ListView with Data Binding set up. I have a transform function attached to the binding of a ListSection. But if my transform function doesn't return data the ListItem expects, it crashes the view/window or throws an error which is unusable (unknown error). So for example 
<ListItem myLabel:text="{labelText}" />
But transform doesn't give the variable labelText, or (not 100% confirmed yet) it returns null/empty result. In this case it goes wrong. Happens with Alloy coupled with 5.2.0 and 5.2.1 and 5.3.0

Comments

  1. Kota Iguchi 2016-04-15

    Maybe related to TIMOB23216 but [~topener] could you give us a sample code so we can reproduce the issue on our side?
  2. Rene Pot 2016-04-15

    Hi, the example in the description is already basically what the problem is. Data provided in transform but not used in ListItem is fine, but data to-be-used in the ListItem that is not provided from the transform crashes the view
  3. Kota Iguchi 2016-04-17

    [~topener] Could you confirm what kind of value labelText variable have? I think you are guessing it was empty or null?
  4. Rene Pot 2016-04-17

    The data property was missing. Neither null or empty.
  5. Kota Iguchi 2016-04-17

    Hmm I can not reproduce this. I think you mean doTransform returns object but it doesn't have required property, is that right? For example let say we have doTransform like below: 
       function doTransform(model) {
   	return [];
   }
    and then try to bind the missing property ListItem title: 
       <Alloy>
       <Collection id='info' src="info" />
   	<Window class="container">
       <ListView id="list">
           <ListSection id="section" dataCollection="info" dataTransform="doTransform">
               <ListItem title="{title}" />
           </ListSection>
       </ListView>
   	</Window>
   </Alloy>
    It just shows empty List (as expected) and it does not throw "unknown exception". Did I miss something in this case?
  6. Rene Pot 2016-04-17

    I had troubles with this, but for me it never returned an empty array or object. I guess it should return something like this 
       function doTransform(model) {
   	return {
               test: "text",
               showTitle: false
           };
   }
    and keep the listview the same
  7. Kota Iguchi 2016-04-17

    [~topener] Yeah, I tried something like that too but app doesn't crash for me... Now I'm guessing that doTransform contains wrong property that causes ListView crash. Could you dump the actual value? Or at least can you provide a property names? 
       function doTransform(model) {
       Ti.API.info(JSON.stringify(model));
       return {
           test: 'text',
           showTitle: false
       };
   }
  8. Rene Pot 2016-04-22

    Figured it out... turned out to be either null or undefined. I was trying to get() a property on a model that didn't exist. Although getting a non-existing property from a model didn't crash anything, trying to insert it in the view did. So that is the actual bug report
  9. Kota Iguchi 2016-04-25

    Glad to hear you figure it out...Could you provide a simple sample code that reproduce the issue [~topener] ? From what you described, I would imagine like this: 
       var book = Alloy.createModel('book', {title:'Green Eggs and Ham', author:'Dr. Seuss'});
   var unknown_prop = book.get('unknown_prop');
   book.save(); // crash??
  10. Rene Pot 2016-04-25

    Hi, this has nothing to do with models and saving them. It has to do with DataBinding in a ListView. 
        function transform(model){
        return {
           text: model.get('unknown_prop')
       };
    }
    And that property is used in the xml 
        <ListItem myLabel:text="{text}" />
  11. Kota Iguchi 2016-04-26

    I still can't reproduce this but I'm trying in various way. Just in case, which version of alloy are you using? Alloy prior to 1.8.1 had a issue around model binding (TIMOB-20577) so make sure you use Alloy 1.8.1 or 1.9.x. (alloy --version)
  12. Rene Pot 2016-04-26

    Can confirm, behaves better with 1.8.# and crashes with 1.7.#
  13. Kota Iguchi 2016-04-26

    Awesome, so you mean crash is fixed in 1.8.x? I think I found a potential workaround for a View crash with alloy on my side...adding setTimeout on updating model (save) makes View stable for me. I know this is dirty workaround but just in case, hope this works for you too. 
        function updateStatus() {
      setTimeout(function () {
        var todo = todos.get(id);
        todo.set({
             done: todo.get("done") ? 0 : 1,
             date_completed: moment().unix()
         }).save();
      }, 500);
    }
  14. Rene Pot 2016-04-26

    Yeah correct, apologies for that!
  15. Kota Iguchi 2016-04-26

    Awesome! Resolving this ticket as duplicate of TIMOB-20577.
  16. Lee Morris 2017-03-21

    Closing ticket as duplicate with reference to the above comments and links.

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