SEEM3460 Tutorial GUI in Java

Some Basic GUI Terms Component (Control in some languages) the basic GUI unit something visible something that user can make action with Container component that can hold other components a component hierarchy can be formed Frame (Form in some languages) window that brings components to the display

Typical Components Button Label TextField (TextBox) Panel List (ListBox) Choice (ComboBox) CheckBox CheckBoxGroup (RadioButton) Menu …

Typical Properties of a GUI unit location size border (color, width, style) background color foreground color text font (name, size, style) components (only for containers) visible: determine whether it is displayed graphic: for custom drawing

Action and Event Different components captures different actions (e.g. a click, a key press, a mouse move) Actions or program statements raise events Event handler/action listener are classes which contain methods (actionPerformed(Event) for Java) registered to be invoked when events are raised. This is called event handling A component can register an action listener to handle all actions it captures The flow of GUI programs are event-based

Layout: Special from Java Save programmer’s effort to arrange components by automatically setting the right size and position Most typical Layout Managers: FlowLayout: Left to right GridLayout: N by M BorderLayout: N, E, S, W, Center