Typically, the label's painting area is exactly the size needed to paint on the label and thus label alignment is irrelevant.For more information about X and Y alignment, see How to Use Box Layout.Useful methods in this class: add Observer(), remove Observer(), notify Observers(), set Changed() and has Changed().

If the component is interactive and has a certain state, use a button instead of a label. label1 = new JLabel("Image and Text", icon, JLabel. When this occurs, you can improve your program's accessibility by using the Note: In the following API, do not confuse label alignment with X and Y alignment.

By specifying HTML code in a label's text, you can give the label various characteristics such as multiple lines, multiple fonts or multiple colors. If you need to paint the label's background, it is recommended that you turn its opacity property to "true". Image Icon icon = create Image Icon("images/middle.gif"); . CENTER); //Set the position of the text, relative to the icon: label1Vertical Text Position(JLabel. CENTER); label2 = new JLabel("Text-Only Label"); label3 = new JLabel(icon); method is similar to that used throughout this tutorial. X and Y alignment are used by layout managers and can affect the way any component — not just a label — is sized or positioned.

protected Property Change Listener create Action Property Change Listener(Action a) Creates and returns a Property Change Listener that is responsible for listening for changes from the specified Action and updating the appropriate properties.

boolean is Validate Root() Calls to revalidate that come from within the textfield itself will be handled by validating the textfield, unless the textfield is contained within a JViewport, in which case this returns false.

Observer and Model View Design Principles: In the example application, the data is the subject and the display is the Observer. The design principles are not only applied for connecting UIs and model objects; in Java Swing the GUI objects like a JButton publish GUI-related events.

In our introduction to threading with Swing, we said that any updates to the user interface must happen on the event dispatch thread.

The class creates an Observable object and adds (or registers) the Main Window as an Observer (to the Observable).

This class extends Observable; has a method to notify (or inform) of (the data) changes in this.

This is informed of changes in a Observable object (and, can receive notifications from multiple Observable objects).

This has only one method, method receives these notifications and optional data.

The point is: whatever GUI component it is, we must make sure that the code to update it is inside a call to .