Adding tabs dynamically in tabhost from database - xamarin.android

Question

I try to add tabs in tabhost dynamically from data which I extract from database. But usually I get exceptions. I want to use this tabhost in activity.
This is my code :
Main.cs
[Activity (Label = "Main",Theme = "#style/Theme.Splash")]
public class Main : Activity
{
TabHost tabHost;
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
SetContentView (Resource.Layout.activity_main);
tabHost = FindViewById<TabHost>(Resource.Id.tabHost1);
LocalActivityManager localActMgr = new LocalActivityManager(this, false);
localActMgr.DispatchCreate(bundle);
CSList<CategoriesArticlesConfig> categories = CategoriesArticlesConfig.List();
tabHost.Setup(localActMgr);
foreach (CategoriesArticlesConfig categorie in categories)
{
Intent i = new Intent();
i.SetFlags(ActivityFlags.NewTask);
i.PutExtra("CategorieID", categorie.CategorieArticlesConfigID);
i.SetClass(this, typeof(AfficheArticlesTab));
TabHost.TabSpec tab = tabHost.NewTabSpec("tab_"+categorie.CategorieArticlesConfigID);
tab.SetIndicator(""+categorie.Nom, Resources.GetDrawable(Android.Resource.Drawable.IcInputAdd));
tab.SetContent(i);
tabHost.AddTab(tab);
}
}
}
AfficheArticlesTab.cs
class AfficheArticlesTab : Activity
{
public AfficheArticlesTab() { }
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.activity_configuration);
GridView gridView = FindViewById<GridView>(Resource.Id.gv_item_articles_gridview_articles_tab_main_activity);
LayoutInflater layoutInflater = (LayoutInflater)GetSystemService(Context.LayoutInflaterService);
View view = layoutInflater.Inflate(Resource.Layout.gridview_articles_tab, null);
int CategorieID = Intent.Extras.GetInt("CategorieID");
CategoriesArticlesConfig categorie = CategoriesArticlesConfig.ReadFirst("CategorieArticlesID="+CategorieID);
gridView.Adapter = new ListArticleConfigAdapter(this,categorie.ArticlesConfig.ToList<ArticlesConfig>());
}
}
activity_main.axml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:minWidth="25px"
android:minHeight="25px"
android:background="#drawable/background_simple"
android:padding="5dp">
<FrameLayout
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/frameLayout1"
android:layout_margin="5dp"
android:layout_weight="0.5">
<LinearLayout
android:orientation="vertical"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/linearLayout11">
<LinearLayout
android:orientation="horizontal"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/linearLayout12"
android:layout_weight="4">
<LinearLayout
android:orientation="vertical"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/linearLayout13"
android:layout_marginTop="14.0dp"
android:layout_marginLeft="8.0dp">
<LinearLayout
android:orientation="horizontal"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/linearLayout18">
<TextView
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:id="#+id/tv_num_ticket_activity_main" />
<TextView
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:id="#+id/tv_num_caissier_activity_main"
android:layout_marginLeft="10dp" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/linearLayout14">
<LinearLayout
android:orientation="horizontal"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/linearLayout15"
android:layout_weight="0.1">
<EditText
android:inputType="numberDecimal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/ed_zone_main_activity"
android:layout_weight="0.16"
android:layout_marginTop="0.0dp" />
<TextView
android:text="#string/qte_value"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/tv_qte_value_main_activity"
android:layout_weight="0.3"
android:layout_marginRight="2.5dp"
android:layout_marginLeft="13.3dp"
android:layout_gravity="center_vertical"
android:gravity="right"
android:layout_marginTop="0.0dp"
android:textSize="20sp" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
<ListView
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/listView1"
android:layout_weight="1"
android:layout_marginTop="8.0dp" />
</LinearLayout>
</FrameLayout>
<LinearLayout
android:orientation="vertical"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/linearLayout17"
android:layout_weight="0.3">
<FrameLayout
android:minWidth="25px"
android:minHeight="25px"
android:id="#+id/frameLayout2"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_weight="0.15">
<LinearLayout
android:orientation="vertical"
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/linearLayout5">
<TabHost
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/tabHost1">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:id="#+id/linearLayout19">
<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>
</FrameLayout>
<LinearLayout
android:orientation="horizontal"
android:minWidth="25px"
android:minHeight="25px"
android:id="#+id/linearLayout16"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_weight="0.85">
<Button
android:text="#string/total"
android:id="#+id/bt_total_activity_main"
android:textSize="16sp"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#drawable/button_selector_rouge" />
<Button
android:text="#string/quantitee"
android:id="#+id/bt_quantitee_activity_main"
android:textSize="16sp"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#drawable/button_selector_enter" />
<Button
android:text="#string/code_barre"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/bt_code_barre_activity_main"
android:layout_weight="1"
android:textSize="16sp"
android:background="#drawable/button_selector_enter" />
<Button
android:text="#string/annuler"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/bt_annuler_activity_main"
android:layout_weight="1"
android:textSize="16sp"
android:background="#drawable/button_selector_enter" />
<Button
android:text="#string/remise"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/bt_remise_activity_main"
android:layout_weight="1"
android:textSize="16sp"
android:background="#drawable/button_selector_enter" />
<Button
android:text="#string/attente"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/bt_attente_activity_main"
android:layout_weight="1"
android:textSize="16sp"
android:background="#drawable/button_selector_enter" />
</LinearLayout>
</LinearLayout>
03-03 13:19:08.004 E/mono ( 7331): Unhandled Exception:
03-03 13:19:08.004 E/mono ( 7331): Java.Lang.NullPointerException: Exception of type 'Java.Lang.NullPointerException' was thrown.
03-03 13:19:08.004 E/mono ( 7331): at Android.Runtime.JNIEnv.CallVoidMethod (intptr,intptr,Android.Runtime.JValue[]) [0x00023] in /Users/builder/data/lanes/monodroid-lion-monodroid-4.6.6-branch/6d7480e9/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:368
03-03 13:19:08.004 E/mono ( 7331): at Android.Widget.TabHost.AddTab (Android.Widget.TabHost/TabSpec) [0x0003e] in /Users/builder/data/lanes/monodroid-lion-monodroid-4.6.6-branch/6d7480e9/source/monodroid/src/Mono.Android/platforms/android-14/src/generated/Android.Widget.TabHost.cs:762
03-03 13:19:08.004 E/mono ( 7331): at SymaMobile.Droid.Main.OnCreate (Android.OS.Bundle) [0x000e8] in f:\PFE\VS2012\SymaMobile\SymaMobile\SymaMobile.Droid\Activities\Main.cs:41
03-03 13:19:08.004 E/mono ( 7331): at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ (intptr,intptr,intptr) [0x00010] in /Users/builder/data/lanes/monodroid-lion-monodroid-4.6.6-branch/6d7480e9/source/monodroid/src/Mono.Android/platforms/android-14/src/generated/Android.App.Activity.cs:1859
03-03 13:19:08.004 E/mono ( 7331): at (wrapper dynamic-m

Answer 1

I find it :)
Firstly, you should extends TabHost.ITabContentFactory
public class Main : Activity, TabHost.ITabContentFactory
Secondly, you should add a NewTabSpec in my tabhost.
tabHost.AddTab(tabHost.NewTabSpec("tab_" + categorie.CategorieArticlesConfigID).SetIndicator(createTabView(tabHost.Context, categorie.Nom)).SetContent(this));
And finally, you use the implemented method CreateTabContent like this:
public View CreateTabContent(string tag)
{
LayoutInflater layoutInflater = (LayoutInflater)GetSystemService(Context.LayoutInflaterService);
View view1 = layoutInflater.Inflate(Resource.Layout.gridview_articles_tab, null);
View view2 = layoutInflater.Inflate(Resource.Layout.list_item_article_configuration, null);
View view3 = layoutInflater.Inflate(Resource.Layout.tab_item, null);
GridView gridView = view1.FindViewById<GridView>(Resource.Id.gv_item_articles_gridview_articles_tab_main_activity);
CategoriesArticlesConfig categorie = CategoriesArticlesConfig.ReadFirst("CategorieArticlesConfigID=" + tabCatID[tabHost.CurrentTab]);
gridView.Adapter = new ListArticleTabAdapter(this, categorie.ArticlesConfig.ToList());
gridView.ItemClick += gridView_ItemClick;
return view1;
}
Thanks,