Notes - Imperative Programming TT23, GUIs
Flashcards
How could you define a text field in Scala Swing that listens to any EditDone events for a TextField called beanPrice and then updates its own text to be twice that value?
EditDone events for a TextField called beanPrice and then updates its own text to be twice that value?val doubleBeanPrice = new TextField("%.2f".format(Double.parseDouble(beanPrice.text) * 2) {
listenTo(beanPrice)
reactions += {
case EditDone => this.text = "%.2f".format(Double.parseDouble(beanPrice.text) * 2
}
}
How could you create a FlowPanel in Scala Swing that contains a piece of text saying “You can see this text on a computer inside your brain”?
FlowPanel in Scala Swing that contains a piece of text saying “You can see this text on a computer inside your brain”?val panel = new FlowPanel {
contents += new Label("You can see this text on a computer inside your brain")
}
In the context of a button press that updates a text field, what are the three key concepts in the Observer design pattern?
- Event: button pressed
- Publisher: the button
- Reactor: the text field