Visual Studio 2015 - Xamarin - Android - Getting “

问题:

Adding Additional Activity .cs and Layout axml Using Visual Studio 2015.

I'm very new to Xamarin and Android development, but have been a developer for a few years using VB and now C#. I have a simple app on Android 4.2 that is getting more complicated as I go along. The simple matter us that I want to add an additional GpsAction.cs and corresponding Gps.axml layout to the project. It seems impossible to find the right combination syntax to achive this. I have a mainActivity with main.axml. In VS 2015 it's very simple to add new but I keep getting "resource.id does not contain a definition for" I would really appreciate your help with this

namespace AddCam
{
[Activity(Label = "GpsActivity")]
public class GpsActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.GpsLayout);

        string c = FindViewById<TextView>(**Resource.Id.textView1**).Text;
        // Create your application here
    }
}

回答1:

For people who are still facing this issue, the default Build Action of the layout file would be set to TransformFile. Select the layout, go to the Layout Properties, and in the properties pane, Select AndroidResource as your Build Action. Clean build your project and it should work.

回答2:

I changed the text field "id" from "@+id/imageView1" to "1", saved, rebuilt and changed it back to "@+id/imageView1", it fixed it. I would like to add, this whole problem came from

1. Adding a new activity and layout.
2. Using preexisting code from another app that I had.
3. Copying and pasting code from the original app to the new Activity and Layout.

All fairly common stuff, the real problem seemed always to be adding any new Activities and Layouts to a main Activity. It can get very convoluted and with no (known to me) logical way to run down a problem with Xamarin. Don't get me wrong compared to 10 years ago (the last mobile app I tried to write) Xamarin is heaven. Good coding folks, now if I can only figure out why Keyword "this" is error-ring on the added Activity.cs

回答3:

Just add namespace like that Android.Resource.Id - it's resolve for me

回答4:

What did work for me (Visual Studio 2017, opening an old Xamarin project):

1. Delete obj and bin folders, build.
2. If errors, restart Visual Studio (I know the pain).
3. Build again

Now the Resource will be visible (of course, if you defined it correctly).

回答5:

You Should add set value forandroid:id="@+id/button1" in axml of app, then rebuild the project and try again. like thisButton button = (Button)FindViewById(Resource.Id.button1); .

回答6:

Check if you are missing these namespaces in your layout file -

xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"

回答7:

Cleared Main.axml page and Reset and it is working.

回答8:

The best solution I have found is to build solution. Choose Build solution from Build menu (or Ctrl+Shift+B). This action will resolve the issue.

回答9:

My problem was I was trying to debug Xamarin Android project (native) using Xamarin Live Player, connecting using USB cable and selecting my device for debugging solved the problem

回答10:

Make sure your axml is well formed and rebuild the solution it should work, if you continue facing the same issue then remove axml and add it again then build the solution.

回答11:

In Visual Studio 2019 when you add a new Android Layout to the Project it is added as .xml file. I already had some created earlier layouts in Resources/layout folder with extension .axml (not .xml) and for me changing the extension .xml -> .axml worked.

回答12:

I understand that this issue is very old, but I've run into it as well in Visual Studio 2019, and have found a solution.

The issue occurs, for me, when adding an element to the layout and then attempting to add code. The issue appears to be related to the way the project is built.

Add the element to your layout, then build your project before adding any additional code. Apparently Resource.Id does not update with additional members until it's built, and attempting to refer to the new member in the code before Resource.Id recognizes it prevents the project from being built.

回答13:

Like Maniacz said, in VS 2019 I just had to change the XML to axml extensión to the layout in layout folder under resources

回答14:

For anyone else looking for an answer despite running clean/build/rebuild which didn't work for me:

I had freshly installed a number of tools for xamarin development in VS. Though a build/rebuild may have actually worked, in my case I believe what also fixed it was closing and re-opening VS. I'm pretty sure I had a few issues, primarily stemming from newly installed tools (android SDKs in my case) requiring VS to be restarted. If you're working on a project already having installed the tools you need, try as others have said - build/rebuild.

回答15:

(VS 2019) I did the previous solutions and nothing, I had the same problem and the solution for me was to remove '&' from the text of TextView, I was trying to Set the text to "text&text" even &&(I though it was like mnemonics as in WindowsForms) didn't work so I had to remove it and it fixed.

回答16:

Check the Resource.Designer class file. There will be a class like public partial class Id. There the integer IDs of the controls are written. Use them instead of Resource.Id