@SteffT wrote:
Hi everyone,
we have an existing cordova app, that we want to migrate to ionic. We did some progress, but faced performance issues when migrating a list of items. This list can hold several hundred items. When the list is being displayed the app freezes for serveral seconds. When searching for a cause, we found that the template containing the list was 'executed' multiple times: we added expressions that output console.log and these log entries were written 5-9 times (the number seems to be constant for a certain app).
We created a test app from the Tabs-started sample and changed only one template and its controller:
<ion-view view-title="Account">
<ion-content>
<span>{{Logging('rendering view')}}</span>
<ion-list ng-repeat="item in items">
<ion-item>
{{item}}
<span>{{Logging('rendering '+item)}}</span>
</ion-item>
</ion-list>
</ion-content>
</ion-view>Our app actually uses ion-list within another ion-list since we are grouping items, but i believe this is less important here.
Logging simply does a console log:
$scope.Logging = function(text)
{
console.log(new Date()+ ' : ' +text);
}Opening the view with a list of 3 items outputs the following on the console:
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering view
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 1
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 2
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 3
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering view
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 1
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 2
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 3
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering view
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 1
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 2
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 3
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering view
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 1
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 2
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 3
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering view
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 1
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 2
Wed Aug 03 2016 22:12:30 GMT+0200 (CEST) : rendering Item 3
I would have expected to see 'render view' once and each 'render item 1' once. But instead it is 'executed' multiple times.For a list of several hundred items that results is a severer performance decrease. Like mentioned this is working without significant delay in a cordova jquery app.
Has someone experienced something similar and found a solution, are we doing something wrong or has anyone an idea what we could try to improve the performance?Many thanks!
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