Trying to navigate from one page to another page by using
await Navigation.PushAsync(new Page2());
But getting,
System.InvalidOperationException: PushAsync is not supported globally on Android, please use a NavigationPage.
new NavigationPage(new Page2());
And
MainPage = new NavigationPage(new App6.Views.SplashPage());
Also not working
Your Application.MainPage page should be a NavigationPage in order to support PushAsync navigation method.
Example:
// In App.cs
MainPage = new NavigationPage(new MyContentPage());
// Elsewhere in your solution with respect to corner cases
await Navigation.PushAsync(new MyContentPage2);
Official documentation has nice examples and a good read.
Related
I need to route pages A -> B -> C -> D, once I got into D, I need to use the navigation button back to page D -> A. I am trying to implement this scenario IOS and Android in Xamarin Forms.
Please help
Your case use the Navigation.PopToRootAsync ();
Navigation.PopToRootAsync (); This method pops all but the RootPage off the navigation stack, therefore making the root page of the application the active page.
Navigation.PopAsync (); This causes the Page2Xaml instance to be removed from the navigation stack, with the new topmost page becoming the active page.
The following doc explains well about Xamarin.Forms Navigation.
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/navigation/hierarchical
Inside the "D" page override the "OnBackButtonPressed" and inside the function iterate trough the pages you no longer need and remove them one by one.
Pseudo code:
protected override bool OnBackButtonPressed()
{
foreach (var page in Navigation.NavigationStack)
{
//find the pages you want to remove
Navigation.RemovePage(PageYouFound);
}
//Set new page
return base.OnBackButtonPressed();
}
You can oveeride OnBackButtonPressed Event and use Navigation.PopToRootAsync
protected override bool OnBackButtonPressed()
{
Navigation.PopToRootAsync();
return base.OnBackButtonPressed();
}
Does anyone know how a navigation drawer similar to the one in the Sonos app can be implemented? I have checked both Android and iOS versions of the app and see that the navigation drawer has been implemented in the same way for both platforms.
The two key things that I like and want to implement are:
the slide out drawer is below the navigation bar. When it slides out, the navigation bar is still visible
it appears as if it is the drawer that slides out, rather than the detail view moving to the right. I've noticed that the default master detail page slides out in a different way and it's not what we want.
Have a look at the images below so see I mean.
thanks
Although not technically a good practice, if you put a MasterDetailPage into a NavigationPage, it will slide out like in the above pictures. Here's how you do that:
In the App.cs constructor or your app's OnStart() method:
MainPage = new NavigationPage(new MyMasterDetailPage()) {
Title = "Your Title"
};
Create a new MasterDetailPage called MyMasterDetailPage.
In the constructor, add the following code:
Detail = new HomePage();
Master = new MenuPage()
{
Title = "Menu"
};
You then need to create a ContentPage for both HomePage and MenuPage.
One issue that you will run into if you use this method, is that if you don't call MyMasterDetailPage as the first page upon opening the app, the three horizontal bars on the NavigationBar won't appear, which will make it hard for users to tell there is a drawer. So if you need users to go to a login page or another page before your MasterDetailPage, you may want to find another implementation.
I navigate forward using Frame.Navigate but when I press the hardware back key on my phone I end up on the start screen and not the page I just visited.
What might be wrong?
The reason behind your problem is, you are creating a Blank Page. If you're creating a blank page, you should define what the app has to do when the back button is fired.
Better, consider adding "Basic page". It will have backstack by nature. If you are navigating from the MainPage to the Basic Page and when you pressed back button at the Basic Page it will back to the MainPage.
I hope this could solve your problem!
If you want to use Blank Page in your application, you need to use like this on your page where you wanna override back button:
add this in your header:
using Windows.Phone.UI.Input;
and then in your constructor:
HardwareButtons.BackPressed += HardwareButtons_BackPressed;
add this anywhere in your code:
void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
HardwareButtons.BackPressed -= HardwareButtons_BackPressed;
this.Frame.Navigate(typeof(MainPage));
e.Handled = true;
}
You've probably forgotten to use the NavigationHelper included in the template of the universal app.
You should use it like this on every page:
NavigationHelper _navigationHelper;
public LoginPage()
{
this.InitializeComponent();
_navigationHelper = new NavigationHelper(this);
}
In a Hub view App with subItems Pages, my question is when I navigate to a sub item detail Page and then use command navigate goback, the view always returns to pageroot hub section01.
How can I return the MainHub Page to the original calling section that went to the sub page in the first place?
My research has been fruitless. I don't think snaps are my answer but hey any advice is appreciated.
I apologize if this is a very simple question but...
Thx.
Ok. Thanks for the answers. After looking at this problem for three days I have found a solution but not quite an answer.
this.NavigationCacheMode = Windows.UI.Xaml.Navigation.NavigationCacheMode.Enabled;
By enabling Navigation Caching the page will return to it's sender position. However I still desire to return to the Hub root page to a specific section. If anyone still has info on how to achieve this I would be grateful.
Seasons Greetings.
Well the newbie here has also discovered the MyHub.ScrollToSection(MyHub.Sections[0]);
This allows you to navigate directly to a section thereby bringing it into the current view.
I'm trying to find an answer to the same question. This is what I've found so far. I welcome any better solutions.
Option 1
Enable caching for the page. Note that this must be set in the page constructor or XAML. This will increase memory usage but will improve performance of your app when you navigate back to a cached page.
this.NavigationCacheMode = Windows.UI.Xaml.Navigation.NavigationCacheMode.Enabled;
More information here: http://msdn.microsoft.com/en-us/library/windows/apps/xaml/windows.ui.xaml.controls.page.navigationcachemode.aspx
Option 2
Manually save a controls state between page navigations. The example below is using the NavigationHelper class which is added to a new Windows Store project by default.
private void OnNavigationHelperSaveState(obj sender, SaveStateEventArgs e)
{
e.PageState["SelectedSection"] = this.MainHub.SectionsInView;
}
private void OnNavigationHelperLoadState(obj sender, LoadStateEventArgs e)
{
if (e.PageState != null)
{
var sections = e.PageState["SelectedSection"] as IList<HubSection>;
if (sections != null && sections.Any())
{
this.MainHub.ScrollToSection(sections[0]);
}
}
}
More information here: http://msdn.microsoft.com/en-gb/library/windows/apps/hh986968.aspx
you could get the Hub's descendant scrollviewer and register to scrollchanged events, store the scrollOffsets and restore them as soon as the user navigates back to the page by applying the values to the hub's scrollviewer.
I guess you would have to register to the hub's loaded event to get the descending scrollviewer (you can use an Extension method from WinRt XAML Toolkit that allows you to get the descendants by Type (e.g. Scrollviewer)
greetings!
you can delete un back stack with this :
if(this.Frame.CanGoBack)
{
this.Frame.BackStack.RemoveAt(0);
}
Have you tried what i suggested?
Unforunately Hub can't be extended to do this and access it's Scrollviewer so you have to do this with an attached Property or plainly in your page.cs .
First you register an handler for the Loaded event of your hub. In the handler you get the descending scrollviewer (with the help of WINRT XAML Toolkit maybe) and register for it's ViewChanged Event.
You store the paremeters you like somewhere they don't get deleted on page navigation and restore and attach them to the scrollviewer on backwards-navigation.
I can give you example code in the afternoon.
Greetings
It's not a ridiculous request. Try this:
public static class Concurrency
{
public static HubSection GotoSection { get; set; }
}
public class MainPage : Page
{
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (Concurrency.GotoSection != null)
MainHub.ScrollToSection(Concurrency.GotoSection);
Concurrency.GotoSection = null;
base.OnNavigatedTo(e);
}
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
Concurrency.GotoSection = MainHub.SectionsInView.First();
base.OnNavigatedFrom(e);
}
}
The reason this.NavigationCacheMode = Windows.UI.Xaml.Navigation.NavigationCacheMode.Enabled; may not be the correct solution is because you might want your hub to be refreshed. If the detail page resulted in an edit (or especially a delete) a back navigation would show stale data, and subject your app to un unexpected state if the user interacts with dead data.
Best of luck!
Enable cache mode on your page at initialization
public MainHubPage()
{
. .......
this.NavigationCacheMode = NavigationCacheMode.Enabled;
.......
}
You need to add Loaded method to Page constructor.
MainHub.Loaded += async (s, e) => await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
//here you can scroll
MainHub.ScrollToSection(Loyaltysection);
});
I am creating a silver light application using Navigation app template. It is for internal use and hence uses windows authenticatoin. There is a dashboard page which shows couple of records filtered by logged in users id. To get the user id (which is an int) I call a web service by overriding the GetAuthenticatedUser and pass the username (from IPrincipal). This service takes some time to return the details.
When I navigate to dashboard app, it renders completely with no data because the user service is a async operation and I am not able to make the rendering wait till my GetAuthenticatedUser finishes completely. So I created a Login page which just shows a progress bar till I get the user object and then navigate to dashboard. If someone tries to access the dashboard directly by using the URL, i want them to navigate back to Login page.
So in the dashboard constructor I added the following code
if (!UserService.Current.User.IsAuthenticated)
{
MessageBox.Show("Navigating away");
Frame objContainer = this.Parent as Frame;
objContainer.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
Thogh I get the message box prompt, it does not actually take me to Login page but stays in dashboard page. I also tried putting this code in OnNavigatedTo override with no luck.
I also tried using NavigationService instead of Frame as below, with no luck
if (!UserService.Current.User.IsAuthenticated)
{
MessageBox.Show("Navigating away");
this.NavigationService.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
it still does not work. Does anyone know how to make some page accessible only if I have fully valid user object? if they try to access the restricted page without this, I want them to be able to redirected to Login page, how can this be achieved?
I am using Silverlight 3 Beta
Shreedhar
I finally found a way around this. In the Constructo i Hooked up the Loaded event handler and in the event handler I am navigating to a different page and it works fine now.
public Dashboard()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Dashboard_Loaded);
}
void Dashboard_Loaded(object sender, RoutedEventArgs e)
{
if (!UserService.Current.User.IsAuthenticated)
{
Frame objContainer = this.Parent as Frame;
if (objContainer != null)
{
objContainer.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
}
}
This piece of code works just fine!
Shreedhar