Question

How do you create an animated dashed or dotted border of an arbitrary shape in Android? In XML (preferred) or programmatically.

See picture below for an example.

Answer 1

Have you seen the PathEffects API demo?
http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/PathEffects.html

It produces precisely an animated line and you can just adjust the path to the edge of your view to create a border. For example:

Define a path by your view parameters / arbitrary shape:

Path path = new Path();
path.addRect(view.getLeft(), view.getTop(), view.getRight(), view.getBottom(), Path.Direction.CW);

Then create a dashed PathEffect with:

PathEffect pe = new DashPathEffect(new float[] {10, 5, 5, 5}, phase);

Then set the associate it with a Paint object and draw:

mPaint.setPathEffect(pe);
canvas.drawPath(path, mPaint);

EDIT: The animated effect comes from continuously changing the phase and redrawing. In the API demo it calls invalidate() in the onDraw() method (which triggers onDraw()…)