findViewByID returns null

Question

First of all: yes, I read all the other threads on this topic. And not only those from this site... (you see, I'm a little frustrated)

Most of them come with the advice to use android:id instead of just id in the XML file. I did.

From others, I learned, that View.findViewById works different than Activity.findViewById. I handled that, too.

In my location_layout.xml, I use:

<FrameLayout .... >     <some.package.MyCustomView ... />      <LinearLayout ... >         <TextView ...             android:id="@+id/txtLat" />         ...     </LinearLayout> </FrameLayout> 

In my Activity I do:

... setContentView( R.layout.location_layout ); 

and in my custom view class:

...  TextView tv = (TextView) findViewById( R.id.txtLat ); 

which returns null. Doing this, my Activity works fine. So maybe it's because of the Activity.findViewById and View.findViewById differences. So I stored the context passed to the customs view constructor locally and tried:

... TextView tv = (TextView) ((Activity) context).findViewById( R.id.txtLat ); 

which also returned null.

Then, I changed my custom view to extend ViewGroup instead View and changed the location_layout.xml to let the TextView be a direct child of my custom view, so that the View.findViewById should work as supposed. Suprise: it didn't solve anything.

So what the heck am I doing wrong?

I'll appreciate any comments.

Answer 1

which returns null

Possibly because you are calling it too early. Wait until onFinishInflate(). Here is a sample project demonstrating a custom View accessing its contents.

Answer 2

Possibly, you are calling findViewById before calling setContentView? If that's the case, try calling findViewById AFTER calling setContentView