I'm developing right now an iOS mobile application using Flash Builder and last SDK.
i'm using a viewNavigator and handle gestureswipe event to push and pop views on it.
It seems that there is a noticeable delay between the gesture and the effective swipe animation. I think that this is because Flex create a new instance of the view each time your push it, so is there a way to effectively manage a view cache and/or force the view to be reused between push/pop (and so without crippling the memory management on a mobile device..)
View has destructionPolicy. default "auto" means to create it every time
Related
I am implementing Prism in a new Xamarin Forms App. I have been using Rg.Plugins.Popup in the app before converting to Prism.
What are the limitation on the Prism Dialogs vs Prism.Plugin.Popups?
What are some examples when you would use one over the other?
Thank you!
Rg.Plugins.Popup is a popular plugin for Xamarin.Forms which accesses the native functionality to provide a "Modal Popup" which traditionally has not been achievable with Xamarin.Forms.
Dialogs in Prism 7.2
If you're using Prism 7.2 you'll find that the DialogService locates the currently displayed page and then "reparent's the content". Or in other words it takes the content of the active Content Page and places it as the root child of an AbsoluteLayout, placing a mask layer and finally your dialog on top. As a result of this approach you'll notice that any navigation bars for instance on the NavigationPage or TabbedPage, or a MasterDetailPage's menu will remain accessible to the user.
While in some regard both the PopupPage and Dialog may look very similar as you can probably tell there is some significant divergence there.
Dialogs in Prism 8
If you're using Prism 8.0 you'll see that we have updated to the latest Xamarin.Forms and as a result we are able to take advantage of a new feature in Xamarin.Forms which allows you to present a Modal Page with a Transparent background. This in effect allows you to replicate the effect of a PopupPage with either some benefits or drawbacks depending on how you look at it.
With Rg.Plugins.Popups you have the ability to push a PopupPage on top of whatever page is currently displayed from anywhere in the app
With Xamarin.Forms page's that have been pushed Modally they are part of your active Navigation Stack
Using the a traditional page with a transparent background and Modal Navigation you in effect have replicated the appearance of what you get with a PopupPage
Limitations
Prism.Plugin.Popups has the benefit of being integrated into the Navigation Service. As such you can inject the Navigation Service into the ViewModel of a PopupPage, and the PopupPage will be dismissed when you navigate away from it to another non PopupPage.
Dialogs are not part of the Navigation Stack tracked by Prism's Navigation Service. Navigation in Xamarin.Forms is dependent on navigating FROM a specific page. Since Prism's NavigationService doesn't know about the Dialog you will need to dismiss the dialog before navigating.
Other Key Differences
Besides what I've mentioned so far the only real difference is that Rg.Plugins.Popup gives you some added animations which honestly I've seen very few people using.
I need to scroll to top the main Interface Controller of an Apple Watch app programmatically after each launch specially if users has left the app after scrolling it down.
EDIT:
This is now possible in watchOS 4. Just use the scrollToObject:atScrollPosition:animated: method.
Unfortunately, this isn't currently possible. WatchKit only provides a method to scroll to the top of a WKInterfaceTable, not an entire interface controller.
The only workaround I've found is to hide every element in the interface controller. This doesn't just hide the element, it completely removes it from the controller. Then when you unhide everything, you'll be back at the top of your content.
I have a Xamarin.Forms page with a map containing numerous pins. I've built a custom iOS renderer to change the image of the displayed pin.
Once I assign the GetViewForAnnotation delegate, my Xamarin.Forms class no longer receives the "Clicked" event. I can access it through the custom renderer, I do believe, but what I want to do when the user taps the title of the pin is push another Xamarin.Forms page to the navigation stack, and I don't know how to give control back to my Xamarin.Forms app from within my Xamarin.iOS app.
I have a feeling I'll need this type of logic in a few other places... where I need to handle a CustomRenderer event but then pass control back to the Xamarin.Forms app for navigation or other purposes.
So I have a couple directions I'd like to go:
1 - More straightforward - get my "Clicked" event to fire in the Xamarin.Forms app when the map's pin is clicked, even though the iOS app is handling the creation of the pin via a CustomRenderer
2 - More advanced and customizable - pass control back to my Xamarin.Forms app (maybe raise an event related to the Renderer level?)
I'd prefer at this time to just get my Clicked event back, but I'm guessing that may not work once I assign the GetViewForAnnotation event in the CustomRenderer.
From what I read, you can detect the annotation click within your renderer.
Within your renderer in the OnElementChanged you can get access to the View in the Xamarin.Forms PCL it relates to.
A few possibilities to consider going forward:-
a) Use MessagingCenter to convey messaging between interests (see
here).
b) Use the standard event raising, i.e. public event
EventHandler<someEventArgs> OnSomeEvent through your View in your
PCL.
c) Use an ICommand approach on your View in your PCL if your
more MVVM orientated, and invoke this way instead.
Once you have your notification back through your View / Page, depending on where your doing things, you can then do a normal navigation based on the information you have been given from your platform-specific renderer in the PCL.
I’m working on an application for Android and iOS, which requires a certain flexibility for one or two views. That’s why we created & implemented a service that translated a basic list of objects into a user interface for both iOS & Android. But now that Xamarin.Forms is released, we decided to replace our service by the one Xamarin provides. I did succeed in creating the views with Xamarin.Forms, resulting in better looking & smoother running pages. But my problem lies in the navigation of it. Here is a little drawing on what I would like to achieve:
I would like my app to start an activity that starts with a custom fragment. After clicking a button on this fragment, I would like the page I created with the Xamarin.Forms api to be added to my current navigation stack! Once the user is finished with the Xamarin.Forms page, it navigates to a second custom fragment, all that without breaking the navigation cycle. Does anybody have an idea on how I can achieve this?
For the iOS developpers: replace Activity with NavigationController & Fragment with ViewController
Take a look at CarouselPage for Xamarin.Forms' own approach. It doesn't look like that's what you need but you can also look at its source code and maybe make a custom renderer yourself.
You may also want to take a look at MVVM
As for the easier/hackier way you'd want to make a button on each page and when the button is tapped execute Navigation.PushModalAsync(nextPage) - there won't be a "< Back" button any more, you may need to implement that yourself if you need it.
If by your meaning of 'current navigation stack' is for using the native Navigation of each platform, then remember that you don't have to use Xamarin.Forms' Navigation Model and functions such like PushAsync.
If you prefer to do Navigation with code specific to each platform then you can do this the same as normal. Just create your stub pages in each platform specific project and set the Xamarin.Forms content for each page from the shared project.
From each platform specific stub page (Activity / UIView / PhoneApplicationPage) you could then execute an Action<> call setting on the shared Xamarin.Forms page to help with the navigation, or alternatively, hook into a custom-event that is raised from the Xamarin.Forms** page back to the platform specific stub page to allow you to do navigation from there.
Like Sten mentioned there won't be any 'Back' button so you will most likely have to do that yourself.
I want to make an application which shows you the schedule for your school.
It should mainly display the current day and allow you to scroll left and right for switching to the day before or the day after the current selected day.
There should also be a settings view.
I'm new to making iOS apps, so which Xcode template should I use?
I think Page-Based Application seems to fit the most, however is this right?
I don't want the page curl transition, just a normal scrolling transition.
I typically start with a Tabbed Application or Master Detail view, but normally just a Tabbed Application and put in a tableview wrapped in a navigation controller. The tabs allow me to structure out different sections of the app and using table views gives you the nice slide in of new views.
Hope that makes sense.