Why is the navigation stack private in Flutter? I am curious as to why the Flutter authors decided to make it hidden as a design choice.
For those interested, the navigation history is referenced as '_history' within NavigtorState.
class NavigatorState extends State<Navigator> with TickerProviderStateMixin, RestorationMixin {
late GlobalKey<OverlayState> _overlayKey;
List<_RouteEntry> _history = <_RouteEntry>[];
final _HistoryProperty _serializableHistory = _HistoryProperty();
Side notes (looking for a response to above question):
Right now I am making a navigation observer that keeps track of the navigation stack using a queue. When push, pop, or remove are called, I update my queue accordingly. I solely use this to keep track of the depth of the navigation stack. This stack depth, combined with WillPopScope allows for me to fine tune when I want a user to be able to pop or not. Without getting into too much detail, I want my selected tab to not be popable to the root route (route: '/'). By knowing the depth is of length 1, I can use WillPopScope to stop a user from popping.
This circles me back to the original question; is keeping track of the stack a bad design choice for Flutter?
I have found limit resources as to WHY the flutter devs chose to make it private.
My one thought is to prevent users from manually editing the history. So why not allow for a public function such as getHistoryLength()?
Many thanks,
-Flutter Newbie
Related
I am building a flutter app. I have a place in the app where you can make infinite loops with
GoRouter.of(context).push(...);
I mean you can navigate to Screen A and then to B and then to A. There are many screens and many possible loops but I want to protect the user from the most obvious one, the A>B>A>B type.
(I don't care about greater loops like A>B>C>A>B>C and alikes)
To do that, I want to check the navigation stack top element and if the element is the same where we would go with a push, I would do a pop.
Problem is that I can't find anything on Google...
Tried:
Googling it, checking API docs, reading IntelliSense
EDIT:
There is a big set of screens and can't know the previous location solely based on the current one.
Use GoRouter.of(context).location
GoRouter.of(context).location gives you the current location
Example:
Route A has route path /routeA
Route B has route path /routeB
GoRouter.of(context).location will return either /routeA or /routeB
Based on which you can make decision to pop() or push() page
I'm trying to make a Gym app. You can add a workout by pressing the + on the appbar, and this takes you to a new screen where you can add the information about all the exercises and the workout name. When you press the check button, it goes back to the main screen where it displays all the workout that you've created, so that if you tap on a list tile it displays all the exercises.
My problem is that I don't know how to pass all the information about the exercises back to the main page. The only thing that I pass back is the workout name. My idea was to pass a Map<String workoutName, List> so that in the main page I have everything that I need. What do you think about it?
P.S. Rn I'm not storing anything in LocalStorage yet, mainly because I don't know what to store I was thinking about storing the Map<String workoutName, List> But I'm a fresh dev on Flutter so there may be easier solutions.
There are many ways to do this. Because of the inevitable growth of your requirements, I suggest going with the most common way to both pass variables and control your state. Meaning: when your variables change, when you return to your original screen, the screen also rebuilds to show your new information. Riverpod has become the successor to the previously Flutter team recommended State Management solution.
I suggest finding a nice, popular tutorial on Riverpod, perhaps building an app entirely with the video to give yourself a good start.
I'm writing a Flutter app and planning to use GetX for state management (amongst other things). The common design pattern seems to be to use one dart file per view (screen) and for each view to have its own associated controller file.
However, what is the best approach when you have state that isn't just used within a single screen, but instead needs to be shared across screens? It seems wrong to import controllers from one view into the view or controller for another screen. Is there a better way?
Thanks
You can use GetxService: https://pub.flutter-io.cn/documentation/get_state_manager/latest/get_state_manager/GetxService-class.html
As it says: Unlike GetxController, which serves to control events on each of its pages, GetxService is not automatically disposed (nor can be removed with Get.delete()). It is ideal for situations where, once started, that service will remain in memory, such as Auth control for example. Only way to remove it is Get.reset().
I want to implement navigating a tree structure like it is done in e.g. the WinRT file picker. I then want to be able to drop this behavior as part of any page.
My current attempt, is to try and register a secondary FrameAdapter/INavigationService in the container and use that for a frame that is different from the app root frame. So far, I could not get it to work.
My motivation behind that, is, that I do not want to reimplement sth. that the INavigationService already provides.
Basic structure:
ShellView that represents the general app layout (header, footer, navigation) and is currently an OneActive conductor.
Frame control (x:Name="ActiveItem") on the ShellView inside which the hierarchical navigation should occur
The chosen conductor has no relevance yet, since I'll probably have to nest the FrameControl inside another view later to really set up a MDI interface. I'll will want to have multiple screens that should be able to hierarchically navigate
I could not find a CM WP7 example of such a scenario
Can you help me out here?
My problems so far:
How do I access the container from a view code-behind without resorting to using the Application.Current. I figured, it is in the code-behind where I would want to setup the secondary FrameAdapter, since it is here that I have access to the FrameControl
How do I setup the INavigationService so that the initial loading by CM (populating the ActiveItem) is registered with it. There does not seem to be a navigation event for this initial display of the ActiveItem.
Many thanks in advance,
Tobias
PS: I have cross-posted to the Caliburn Micro discussions (Discussion over at CodePlex CM)
In the iPhone application I'm developing, I have a need to return the user to the previous screen they were using when, for instance, the application was interrupted by, say, a phone call.
The application is driven by a navigation controller, and the user may be several layers deep into the application. As such, I think that I need to traverse the navigation controller logic to bring the user to the point that they were previously at, with all return navigation logic n place.
I'm comfortable that I can force the application to navigate down to the required level through code, but I would like to hide the screen switching and animations that would occur while this is going on, thus presenting the user with (apparently) a direct path to their last used screen, rather than showing them the underlying navigation that's occurred.
Could somebody please point me to some method of suppressing the intermediate displays?
Does anyone have other methods to perform this sort of task?
Thanks in advance for all suggestions.
I suggest you take a look at the Three20 project which contains a feature called "URL-based navigation", which might help you, since you only should to store the URL of the current visible view controller, and restore it when the app resumes after the phone call:
TTNavigationCenter is for those grizzled old web developers like myself who want to organize their app by "pages" which can be displayed by visiting a URL.
Your view controllers can simply register URL patterns that they handle, and when those URLs are visited the controllers will be created and displayed. You can also register generic actions that are called when a URL is visited.
TTNavigationCenter also persists and restores the full path of navigation controllers and modal view controllers, so your users can quite the app and come back exactly where they left off.
(source: Three20 Github project)