Hi, there!
I testing screen which contains GridView with items inside. The GridView is built dynamically based on the data stored in the database. Then in tests I manually add one item to database, after that I want to call setState() for showing and checking it. But I have no idea how to do that. Is it real?
Thank you in advance!
I think you don't need to use setState() in this case. Use StreamBuilder to show GridView based on data from firebase. Here's a video of how to implement it https://www.youtube.com/watch?v=MkKEWHfy99Y
Related
i have a page named displayData . On it there is a button if i click on it it shows DraggableScrollableSheet normally it has a button done when i click on it the icon of the page on the bakground (DisplayData) must change .i used a variable in a setState but it doesn't work it's true on the DraggableScrollableSheet but always false in display data
any help !
for this type of cases, there are several solutions, I recommend the use of providers, in this way with the use of 'extends ChangeNotifier' you will be able to detect the changes made without having to use the setState and you will be able to call from any class (or page ) the variables you need
you can use callback methods from on widget to another, if you have much complicated scenario then I suggest using state management libraries like Provider, RiverPod or Bloc.
also
Could you share your code here
How can it update a list view elements without doing pull-to-refresh
If I'm adding an element in a dialog window or from an Api, how to add/update the list view elements automatically.
Should I use StreamBuilder?
Use state management pub like Getx, or something with adlistener.
Yes you can use stream builder and you can also use setstate
setState(() { });
StreamBuilder Widget builds itself based on the latest snapshot of interaction with a Stream. Thus the state of the app changes whenever new elements are added in the list as long as the connection status is active.
You can also use the combination of ListView Builder and setState method, though the state of the app needs to change whenever a new element is added. Earlier StreamBuilder widget was updating the state of the app. Various methods like adding a button to the screen, which can help the user manually change the state; can be used depending on the use case.
You can read more about it from the official docs: setState method
StreamBuilder
This answer is not exactly about updating listView, but updating a widget(PiChart). As listview is also a widget, the implementation will be the same to update without refreshing.
In this method, I am using streamBuilder to update the widget. so need not refresh the app to update the data.
https://stackoverflow.com/a/69800324/13577765
Summary: Planning to show readonly data array in a ListView widget. Data comes in using a Provider. Is it possible to not rebuild the entire ListView every time, and just append a new Tile to it?
Details: The ListView data set coming in is similar to log entries--it's static and only the last item is coming in. Rebuilding the entire ListView every time seems a bit wasteful. Is it possible to have it in such a way that it would append new Tile widgets on incoming data instead?
Please provide some sample code or your code. For now from this question I'll suggest you to take a look on AnimatedList.
So, I need to build custom pages with custom widgets in Flutter, save these pages in memory and recall the custom widgets and their children in the future.
Saving variables is not a problem, as you can use sqlite or json or firebase.
But how can you save an entire page in Flutter??
How can I achieve this?
Please help!
I am trying to build a page that shows a hierarchy of data. The top of the page is built by passed in data. But the dependencies need to query a db and post their results.
For example Team A has players. Under the heading of team A I want to show a list of players on the team. But if I try to add a streamBuilder as a part of screen, I get all sorts of nasty message about some part of the build process not having a height. Its seems that streamBuilder only works as the highest level widget.
So there must be an alternative for building those widgets, can anyone point me to an example of that being used?
An alternative to a StreamBuilder is FutureBuilder - where you can use a Future callback instead of a Stream to fetch a data snapshot for the children Widgets inside it.
However, if you're getting "unbounded height" errors, this is usually thrown by children Widgets with undefined height inside a ListView or Scrollable widget. You'll be needing to set a height for those List items to fix that error.