public virtual void startApp() { Displayable current = Display.getDisplay(this).getCurrent(); if (current == null) { cameraCanvas = new CameraCanvas(this); displayCanvas = new DisplayCanvas(this); decodedTextBox = new DecodedTextBox(this); Display.getDisplay(this).setCurrent(cameraCanvas); cameraCanvas.start(); } else { if (current == cameraCanvas) { cameraCanvas.start(); } Display.getDisplay(this).setCurrent(current); } }