Question

I’ve been through a few tutorials etc and have found that I can acheive the same results defining all of my UI components in code.

For example:

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    TextView tv = new TextView(this);
    tv.setText("hello");
    LinearLayout ll = new LinearLayout(this);
    ll.addView(tv);
    setContentView(ll);
}

is the equivalent of

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

+

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/textview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:text="@string/hello"/>

What are the performance/maintainability benefits of using XML for this?

If a programmer prefers to use code over XML what extra considerations should be made?

Answer 1

What are the maintainability benefits of using XML for this?

1. Separation of logic from presentation. This does help on larger projects when you need to refactor some code. If it is tightly coupled to the UI this job can become time consuming very easily if much of the presentation logic is in code.
2. The structure of XML correlates nicely to the structure of a user interface, i.e., a tree like structure.

What are the performance benefits of using XML for this?

That all depends on the implementation I suppose. I doubt there are any appreciable performance differences, but I honestly don’t know enough to say definitively what they may be.