Change activity background from code

Question

I have an activity with a background:

Answer 1

LinearLayout  vi = (LinearLayout ) findViewById(<id>)
vi.setBackgroundResource(R.drawable.<id2>);

you need to provide the id to your LinearLayout in XML as well....

Answer 2

In java we do like this

Give id to LinearLayout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id=@+id/parentLayout  

Then in code

LinearLayout layout=(LinearLayout)findViewById(R.id.parentLayout);

layout.setBackgroundColor(Color.BLUE);  Or
layout.setBackgroundDrawable(d); Or
layout.setBackgroundResource(resid);

Answer 3

first add LinearLayout id as in your layout xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/linearLayoutid" 
android:minWidth="25px"
android:minHeight="25px"
android:background="@drawable/background_fingerboard" 

and in code part set background as::

LinearLayout  linearLayout = (LinearLayout) findViewById(R.id.linearLayoutid);
 linearLayout.setBackgroundResource(R.drawable.background_fingerboard);