Static Content

using Toybox.System;
using Toybox.Application;
using Toybox.Graphics;
using Toybox.WatchUi;

//////////////////////////////////////////////////////////////////////////
class StaticContentApp extends Application.AppBase
{
    function initialize() { AppBase.initialize(); }
    function getInitialView() { return [ new MyView() ]; }
}

/////////////////////////////////////////////////////////////////////////
class MyView extends WatchUi.DataField
{
    hidden var paintScreen = true; // start with screen painting
    hidden var width, height;

    function initialize() { DataField.initialize(); }
    function compute(dc) { }
    function onLayout(dc) { width = dc.getWidth(); height = dc.getHeight(); }

    function onShow() { paintScreen = true; return true; } // repaint the static screen content in onUpdate

    function onUpdate(dc) {

        // paint the static content once, don't waste compute cycles doing this every second
        if (paintScreen) {
            dc.setColor(Graphics.COLOR_YELLOW,Graphics.COLOR_TRANSPARENT);
            dc.fillRoundedRectangle(20, 20, width -40, height - 40, 15);
        }

        // write dynamic content to screen - update every second
        dc.setColor(Graphics.COLOR_BLACK,Graphics.COLOR_TRANSPARENT);
        dc.drawText(width * 0.5, 40, Graphics.FONT_LARGE, System.getTimer(), Graphics.TEXT_JUSTIFY_CENTER);

        paintScreen = false; // don't recreate static content until onShow runs again
        return true; // tell parent we've handled onUpdate
    }
}