TextView has a method on it called
setTypeface
The code to set the font would look similar to this if your font is at "Assets/Font/Font.otf":
Typeface font = Typeface.createFromAsset(context.getAssets(), "Font/Font.otf");
TextView textView = (TextView)findViewById(R.id.tvTime);
textView.setTypeface(font, Typeface.NORMAL);
Optional:
If needed, you can do this inside the constructor of a class inheriting from TextView, then use that class in your layouts, in case you wanted to use that font in a bunch of different places. Also, if you wanted to do it inside the constructor, you could have the name of the font passed in as a styled attribute in your layout and use that instead of the hardcoded string like above.