Question

I have a launcher activity which contains two tabs which corresponds to two separate activities HeatMap and LiveMkt.

As I read somewhere one can not use following statement in child activities:

Window.RequestFeature(WindowFeatures.CustomTitle);

So I tried following….

OnCreate() of Launcher activity contains :

base.OnCreate (bundle);
Window.RequestFeature(WindowFeatures.CustomTitle);
SetContentView(Resource.Layout.TabView);
//Code to create tabs which points to two activities `HeatMap` and `LiveMkt`

---

OnCreate() of LiveMkt contains :

base.OnCreate (bundle);
SetContentView(Resource.Layout.LiveMkt);
Window.SetFeatureInt(WindowFeatures.CustomTitle,Resource.Layout.TitleBar);
edsearch = (EditText) FindViewById(Resource.Id.edsearch);       
_autoSearchBox = new AutoSearchBox();                       
_autoSearchBox.LoadSearchBox(this,edsearch,lsym);

---

where AutoSearchBox class has LoadSearchBox() which contains

public void LoadSearchBox(Activity activity,EditText edsearch,ListView lsym)
{
    edsearch.TextChanged+= delegate 
    {//Something
     }
}

---

But when I debugged this, I get NullPointerException in LoadSearchBox() for edsearch and lsym even though I have these two elements in LiveMkt and passing them to LoadSearchBox().

LiveMkt.xml contains ListView lsym and TitleBar.xml contains EditText edsearch.

StackTrace:

Exception Details : System.NullReferenceException: Object reference not set to an instance of an object

at AutoSearchBox.LoadSearchBox (Android.App.Activity activity, Android.Widget.EditText edsearch, Android.Widget.ListView lsym)

As I’m new to Mono Android, any help appreciated.

Answer 1

Are you sure that edsearch is not null? The FindViewById method returns null if it couldn’t find the view, so it’s possible that’s what’s happening for you.