XAMARIN: How to FindViewById ??? (Resource not Found)

Question

I'm getting a resource not found error when I try to do this:

    TabWidget tabz = FindViewById<TabWidget>(Resource.Id.tabs);

compiler doesn't see the TabWidget even when it's clearly labeled by id in my Main.axml file

Error CS0117 'Resource.Id' does not contain a definition for 'tabs'

Here's my full code:

<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp">
<TabWidget
    android:id="@android:id/tabs"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:visibility="visible" />
<FrameLayout
    android:id="@android:id/tabcontent"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="5dp" />
</LinearLayout>

EDIT, sorry, this is the full code... I don't know why I didn't copy this last time. The above example is missing TabHost

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TabHost
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:minWidth="25px"
        android:minHeight="25px"
        android:id="@+id/tabHost1">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:id="@+id/linearLayout1">
            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
        </LinearLayout>
    </TabHost>

</LinearLayout>

How can I force the compiler to recognize my tabs id? I've tried rebuilding the resource.designer.cs .. putting the declaration of TabWidget inside all of the activities... nothing works. My C# can't see the TabWidget

full project can be found here:

https://github.com/hexag0d/BitChute_Mobile_Android_a2

I also tried this and it didn't work Xamarin Android Resource file not found

thanks, in advance

Answer 1

About the questions in your comment:

1,

that is very good advice, but one note is that when SetContentView(localLayout); is used inside an activity that already has a content view, it crashes the app.

The app crashed because localLayout in SetContentView(localLayout) is a LinearLayout but a TabWidget needs a TabHost. So you can directly use:

SetContentView(Resource.Layout.Main);

where Main.xaml is like:

<?xml version="1.0" encoding="utf-8"?>

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:theme="@style/MyTheme">

   <LinearLayout
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="5dp">

    <TabWidget
        android:id="@android:id/tabs"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.0"
        android:visibility="visible" />
    <FrameLayout
        android:id="@android:id/tabcontent"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="5dp" />
    </LinearLayout>
</TabHost>

2,

LinearLayout localLayout = FindViewById(Resource.Layout.Main); View whichYouWantToUse_findViewById = LayoutInflater.Inflate(Resource.Layout.Main, null); TextView tv = FindViewById(Resource.Id.textView169); TabHost _tabHost = (TabHost)whichYouWantToUse_findViewById.FindViewById(Resource.Id.tabhost); ' still can't see the tabhost ... I'm losing my mind here

The reason why you cannot see the tabhost is, firt, TabHost is FrameLayout, not LinearLayout, second, Resource.Id.tabhost should be Android.Resource.Id.TabHost. So I edited your code to :

    FrameLayout localLayout = FindViewById<FrameLayout>(Resource.Layout.Main);
    whichYouWantToUse_findViewById = LayoutInflater.Inflate(Resource.Layout.Main, null);
    //TextView tv = FindViewById<TextView>(Resource.Id.textView1);
    TabHost _tabHost = (TabHost)whichYouWantToUse_findViewById.FindViewById(Android.Resource.Id.TabHost);

3,

So the interesting thing is if I change tabhost to tahost ala android:id="@+id/tahost" the resource appears in the designer but when I change to android:id="@+id/tabhost" the resource disappears.. very strange..

The id of TabHost need always be @android:id/tabhost", it cannot be modified to tahost or any others.

So the code in the onCreat Method is like this:

    base.OnCreate(bundle);

    SetContentView(Resource.Layout.Main);
    View whichYouWantToUse_findViewById = LayoutInflater.Inflate(Resource.Layout.layout1, null);
    TextView textInAnotherLayout = (TextView)whichYouWantToUse_findViewById.FindViewById(Resource.Id.textView1);
    textInAnotherLayout.Text = "Yeah";

    TabHost tabHost = FindViewById<TabHost>(Android.Resource.Id.TabHost);
    TabWidget tabWidget = tabHost.TabWidget;
    var tabContent = tabHost.TabContentView;

    FrameLayout localLayout = FindViewById<FrameLayout>(Resource.Layout.Main);
    whichYouWantToUse_findViewById = LayoutInflater.Inflate(Resource.Layout.Main, null);
    TabHost _tabHost = (TabHost)whichYouWantToUse_findViewById.FindViewById(Android.Resource.Id.TabHost);

The following is the old answer.

---

Answer modified: The way to get TabHost and TabWidget in Activity:

TabHost tabHost = this.TabHost;
TabWidget tabWidget = tabHost.TabWidget;

The way to use one resource from one XAML file in the activity for another:

    LinearLayout localLayout = FindViewById<LinearLayout>(Resource.Layout.Main);
    SetContentView(localLayout);
    View whichYouWantToUse_findViewById = LayoutInflater.Inflate(Resource.Layout.layout1, null);
    Button button1 = (Button)whichYouWantToUse_findViewById.FindViewById(Resource.Id.button1);

I download your project and fixed this problem by modifying the property of >android:id

Answer 2

The issue is not with the visual studio compiler but the way that you have declared the id for your View,

If you check this blog by James White you will see how Id and the Layout Attributes actually work in Android,

The Right way of declaring the Id would be something like this android:id="@+id/tabs" whereas what you are doing is this android:id="@android:id/tabs"

Hence, When you do add them and try to find it using Resource.Id.tabs, There is nothing available in Id by the name tabs as it was never added by the Xamarin ResourceDesginer.cs file.

So the end result should actually be something like this :

  <TabHost
    android:id="@+id/tabhost"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"></TabWidget>

        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:id="@+id/tab1"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#ffc916"
                android:orientation="vertical">
        </LinearLayout>
        </FrameLayout>
    </LinearLayout>
  </TabHost>

Also, note that I have replaced all the fill_parent's with match_parent's the reason behind it being that fill parent is now obsolete or you can say replaced (After API-8) and hence must not be used, which can be found here.

Update:

I have updated the way tab host works, Also updated the XML above and I am adding a reference link where you can find the right way of using both the TabHost and TabWidget, Also a good SO example for the same.