How do I toggle between ContentPage and MainActivity Fragment

Question

How do I toggle between ContentPage and MainActivity Fragment

Universal Camera 276

I have a ContentPage showing a Map

from my MainActivity I start a Camera Fragment

    public void BackgroundCameraSetUp()  
    {  
        SetContentView(Resource.Layout.activity_camera);  
        if (null == BundleSavedInstanceState)  
        {  
            BundleSavedInstanceState = this;  
            FragmentManager.BeginTransaction()  
                .Replace(Resource.Id.container, CameraFragment.newInstance())  
                .Commit();  
        }  
    }

my activity_camera in Android

while I am on my ContentPage showing the Map I can launch my MainActivity Camera Fragment successfully.

What I am struggling with is once I am in my Camera Fragment how do I Navigate back to my Map in ContentPage?

I tried without success

            App.Current.MainPage.Navigation.PopModalAsync(new MainPage());

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-11-08T09:12:04.54+00:00

You could try to use App.Current.MainPage = new MainPage() to navigate to the MainPage.

Would it be helpful for you?

If it doesn't work, for further investigation, could you please provide more detailed information about the steps for reproducing this issue or minimal sample?
Universal Camera 276 Reputation points

2022-11-08T16:57:56.223+00:00
Thank you!

I actually converted the following link to Xamarin.Forms

https://github.com/xamarin/monodroid-samples/blob/main/android5.0/Camera2VideoSample/Camera2VideoSample/Camera2VideoFragment.cs

in my App.cs

MainPage = new CameraPage();

CameraPage() has the Map as a ContentPage with Buttons which loads upon launch of the Application. User can push one of the button to launch Camera Fragment per sample above.

This all works great!

var j = App.Current.MainPage.Navigation.ModalStack.Count;

always shows 0 therefore PopModalAsync() is useless????

I just don't know how to toggle between Map and Camera!

Everything works but I just dont
Universal Camera 276 Reputation points

2022-11-09T16:41:44.593+00:00

Thank you @Yonglun Liu (Shanghai Wicresoft Co,.Ltd.)

The conversion was not easy, but I had to rewrite some aspects but now It works great. I can capture videos etc. I can navigate on the map also. This is why I didn't pose the problem in general terms.

Are you saying that android:id="@+id/container" creates a Fragment that cannot be navigated away from? If so, should I rewrite without container. Frankly I don't know why a container was used since there is only one fragment being used.

Supposing there was no container how would you toggle between a Fragment and ContentPage?
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-11-11T03:06:46.077+00:00

In Android, the main role of Fragment is to act as a reusable UI component in Activity.

A Fragment represents a reusable portion of your app's UI. A fragment defines and manages its own layout, has its own lifecycle, and can handle its own input events. Fragments cannot live on their own--they must be hosted by an activity or another fragment. The fragment’s view hierarchy becomes part of, or attaches to, the host’s view hierarchy.

Using ContentView as a reusable UI in Xamarin.Forms is more recommended.

The Xamarin.Forms ContentView class is a type of Layout that contains a single child element and is typically used to create custom, reusable controls. The ContentView class inherits from TemplatedView. This article, and associated sample, explain how to create a custom CardView control based on the ContentView class.

In your scenario, you call a Fragment in your page, which is equivalent to replacing the UI of the current page with ContentView in Xamarin.Forms, because Xamarin.Forms has only one MainActivity.

Therefore, your page has not actually made page jumps, which is why your navigation is not effective.

1 answer

Your answer

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-11-08T09:12:04.54+00:00

You could try to use App.Current.MainPage = new MainPage() to navigate to the MainPage.

Would it be helpful for you?

If it doesn't work, for further investigation, could you please provide more detailed information about the steps for reproducing this issue or minimal sample?
Universal Camera 276 Reputation points

2022-11-08T16:57:56.223+00:00

Thank you!

I actually converted the following link to Xamarin.Forms

https://github.com/xamarin/monodroid-samples/blob/main/android5.0/Camera2VideoSample/Camera2VideoSample/Camera2VideoFragment.cs

in my App.cs

MainPage = new CameraPage();

CameraPage() has the Map as a ContentPage with Buttons which loads upon launch of the Application. User can push one of the button to launch Camera Fragment per sample above.

This all works great!

var j = App.Current.MainPage.Navigation.ModalStack.Count;

always shows 0 therefore PopModalAsync() is useless????

I just don't know how to toggle between Map and Camera!

Everything works but I just dont
Universal Camera 276 Reputation points

2022-11-09T16:41:44.593+00:00

Thank you @Yonglun Liu (Shanghai Wicresoft Co,.Ltd.)

The conversion was not easy, but I had to rewrite some aspects but now It works great. I can capture videos etc. I can navigate on the map also. This is why I didn't pose the problem in general terms.

Are you saying that android:id="@+id/container" creates a Fragment that cannot be navigated away from? If so, should I rewrite without container. Frankly I don't know why a container was used since there is only one fragment being used.

Supposing there was no container how would you toggle between a Fragment and ContentPage?
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-11-11T03:06:46.077+00:00

In Android, the main role of Fragment is to act as a reusable UI component in Activity.

A Fragment represents a reusable portion of your app's UI. A fragment defines and manages its own layout, has its own lifecycle, and can handle its own input events. Fragments cannot live on their own--they must be hosted by an activity or another fragment. The fragment’s view hierarchy becomes part of, or attaches to, the host’s view hierarchy.

Using ContentView as a reusable UI in Xamarin.Forms is more recommended.

The Xamarin.Forms ContentView class is a type of Layout that contains a single child element and is typically used to create custom, reusable controls. The ContentView class inherits from TemplatedView. This article, and associated sample, explain how to create a custom CardView control based on the ContentView class.

In your scenario, you call a Fragment in your page, which is equivalent to replacing the UI of the current page with ContentView in Xamarin.Forms, because Xamarin.Forms has only one MainActivity.

Therefore, your page has not actually made page jumps, which is why your navigation is not effective.

Answer 1

Hello,

It is not recommended to use CameraFragement in Xamarin.Forms, as a matter of fact, using any Android Fragment in Forms is not recommended in Xamarin.Forms.

You could refer to the following documentation and sample about how to use CameraView in Xamarin.Forms.

Best Regards,

Alec Liu.

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Share via

How do I toggle between ContentPage and MainActivity Fragment

1 answer

Your answer