Layout orientation in code

You need to instance LinearLayout. After that you can call setOrientation()

LinearLayout myLayout = ...;
myLayout.setLayoutParams(new LayoutParams(LinearLayout.WRAP_CONTENT, LinearLayout.WRAP_CONTENT);
myLayout.setOrientation(LinearLayout.VERTICAL);

That should do the job :)

For more infos check the Android API.

A working sample below (it's LayoutParams.WRAP_CONTENT, NOT LinearLayout.WRAP_CONTENT)

myLayout.setOrientation(LinearLayout.VERTICAL);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
myLayout.setLayoutParams(layoutParams);

You can use like this one:

LinearLayout myll = (LinearLayout) findViewById(R.id.yourLinearLayout);
myll.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT));
myll.setOrientation(LinearLayout.VERTICAL);

You can't change LinearLayout's orientation using its LayoutParams. It can be done only with a LinearLayout object.

LinearLayout layout = /* ... */;
layout.setOrientation(LinearLayout.VERTICAL);