Is there any problem using StreamBuilder for a single set of data that is fetched from database in my app?
Stream builder is to continuously get data. Even if its a single data or multiple entries if the app needs to fetch data continuously then its good to use Stream builder. Btw fetching single entry will not affect the performance of the app to a great extent. So you should be good to go with Stream builder
https://api.flutter.dev/flutter/widgets/StreamBuilder-class.html
In general terms, no, it is not a problem nor does it greatly effect the performance of the app.
But as always, it depends on more factors. Let for instance say you have a ListView with a bunch of Card in it. And in each Card you have 10 Text-widgets. If you now have a StreamBuilder for each of those Text-widget, and each StreamBuilder does separate requests to your database, and each query is timeconsuming... then yes; it is not optimal. But if it in the end will effect the performance is still hard to say. You'd have to test :) Don't optimize before you need to.
Related
I am writing a SwiftUI app that uses a single Task(priority: .low) to do lots of HTTP requests as a low priority whose results are displayed in a Table.
There's several hundreds of MBs of data being aggregated to display totals, averages etc.
Thing is, I am only creating one Task, but this is causing my UI to hang. Why is this? I think I must have a fundamental misunderstanding around how tasks are created and how they relate to processes and threads.
I am using Mongo's Realm to store the data having become frustrated with Core Data. Does anyone have any experience of agonisingly slow apps using Realm?
There is far too much code to post, but all the HTTP requests are being made using URLSession's async methods. These data are being transformed and saved in my Realm. In any case, I certainly wouldn't expect this to cause the UI to hang! What might be going on?
I know it's tough to triage without code, but as I say there is a lot of it. I’m just after general guidance really, rather than a fix for a very specific issue.
So i have a situation where i make an request from the server for one widget.
The widget is at the home page, lets take the worst case where the data is huge and the request take time.
Should i change the widget to stateless and make a provider which i will initialize before i run the app with all the initial data?
Should i contain all the data of the widgets at home page and deliver theme as props, i miss understood the concept of managing the state here, I'm coming from vue and i try to write my first app and I'm struggling how to structure my data through the routes.
I would like if some one explain or give a good source that show how to initialize data from third party
before the home page reload.
Which approach is better getting all the app data before the app reload or request data every time from db with cash
You might have seen this approach in other apps as well which is to show a splash screen until the data has been loaded and ready to be shown. This approach is mostly used by apps which got large data to load at the start. You could achieve this in your initState like the following.
#override
void initState() {
loadData();
splashTimer = Timer(Duration(seconds: 4), () {
_goToHome();
});
super.initState();
}
State management in flutter is a topic with hot debate, there is no best approach, but using one for sure is better than nothing. However there are exceptions to this, sometime adding a state management to a simple part of the app is not recommended. Regarding your case, it can be done without a full state management solution, by using a FutureBuilder for example. Or it can be also done with Provider, BloC, Redux...
As a naïve general rule, if the state is to be passed down the widget tree more than 1 or 2 levels, you should probably start looking for a state management solution depending on the use case. As I already have said, there is no one best state management solution.
Also, it is ok to use more than one as long as you know what you are doing but in general as a best practice it is not recommended to use more than one.
Regarding the second part of the question, it totally depends on the nature of the data and it's size. If the data is big and it is a small possibility that the user will be using all of it, it is better to load it on demand, also loading all the data upfront will increase the cost on the backend side.
However getting the data upfront, makes the experience more seamless to the user (Not waiting while using the app, but he will have to wait a little extra when the app is first loading).
So as you see it is a balance. Also it is good for the server and the app to do some type of caching since it helps reduce the work on the server side and decrease the bandwidth usage on the phone.
An example for caching images you can use Cached Network Image Link, example from flutter cookbook Link.
So I am using the provider architecture, more specifically, the StreamProvider, to get a list of documents
in a collection called 'Timeline Posts'. One of my goals is to minimize firestore reads and hence costs, so my question is:
If I set listen=false, I know this prevents my UI from updating when there's an update in the documents but does it also prevent firestore from reading that update and charging it as one read. Because I know everytime a document is updated and you're using stream, it counts as a read.
So does listen=false affect both my UI in flutter and the firestore read
From reading the documentation it will still read the changes in the stream. You could switch to a FutureProvider in order to prevent this from happening. If you share your code I would be happy to help you make that switch. A future is something you only would like to read one time and a stream is used for tracking real-time changes.
Why not use Futures instead? I generally use Futures instead of Stream for the situation you are describing.
I ask you a quwstion because i Need to develop an application with background synchronization. I tried to look around but i didn't find something usefull. My requirement Is to do background fetch of datas from apis and save them to database. One sunchronization can be heavy(12k inserits). It this process block UI?
The user could continue to use app while synchronizing.
Thank you
For heavy read/write, you can use https://pub.dev/packages/hive instead of sqlite
Hive have better performance than sqlite
You need to use a dedicated isolate to perform heavy calculations, for that you can use compute
final data = await compute(callback, arguments);
Documentation:
https://api.flutter.dev/flutter/foundation/compute.html
Example:
Flutter- compute method
I want to make all my inherited pages persistent using flutter but I don't know how does anyone know how to accomplish this?
Given the fact that this cannot be answered properly without seeing your implementation, here is what a lot of developers do:
If you application is simple, store each state as a key-value pair. Then store that value and key inside shared preferences.
You would simply need to:
Add shared_preferences: "<newest version>" to pubspec.yaml
Synchronously update the key-value pair in-memory using prefs.setInt('currentState', value);. This persists the data to the disk.
Read your state data suing final counter = prefs.getInt('currentState') ?? 0; and accordingly update your setState method:
Now, this does infact assume that you have a simple application with simple states. If you have more complicated states and actions, then you should consider things like the BLOC pattern in order to organize your app in a way that enables a larger amount of control.