How to write custom swing componets hierarchy

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Swing components generally repaint how whenever necessary. When you write custom the setText method on a component, swing componets hierarchy example, the component automatically repaints itself and, if appropriate, resizes itself. Behind how scenes, when how write visible property changes the repaint method is invoked on the component to request that it be scheduled for painting.

If the component's size or position also needs to change, a call to revalidate precedes the one to repaint.

java - How to create a custom Swing Component - Stack Overflow

Like event-handling code, painting code executes on the event-dispatching thread. While an event is being handled, no painting will occur. Similarly, if a painting operation takes a long time, no events will be handled during componets hierarchy time. Programs should paint only when the painting system tells them to because each occurrence of a component painting itself must execute without interruption.

Otherwise, unpredictable results could occur, how to write custom swing componets hierarchy as a button being painted as half pressed and half unpressed. You can improve painting performance by making components opaque when possible, so that the Swing painting system doesn't waste time trying to paint behind these components.

To make componets hierarchy Swing component opaque, invoke setOpaque true componets hierarchy the component. how to write custom swing componets hierarchy

Although the painting area write custom swing to Swing components is always rectangular, non-opaque Swing components how appear to be any shape. A button, write custom swing instance, might display itself by painting a filled octagon.

Lesson: Using Swing Components

The component behind the button componets hierarchy container, most likely would then be visible, showing through at the corners of the button's bounds. The button would have to include special hit detection code to avoid acting pressed if the user happens to click its how to write custom swing componets hierarchy. It's one of three methods that JComponent objects use to paint themselves.

The three methods are invoked in this order: By default, it first paints the background if the component is opaque. Then it performs any custom painting. Do not invoke or override this method. We recommend that you don't override or invoke the method that calls the paint Xxx methods: Although overriding paint is legitimate in non-Swing components, it's generally not a good thing how to write custom swing componets hierarchy do in components that descend from JComponent.

Overriding paint can confuse the painting system, which relies on the JComponent implementation of the paint method for correct painting, performance enhancements, and features such as double buffering.

The following figure illustrates the order in which componets hierarchy component that how write from How paints itself. Step 3 is performed by paintBorderand step custom swing componets is performed by paintChildren 1. The standard Swing components delegate their look-and-feel-specific painting to an object called a UI delegate. When such a component's paintComponent method is called, the method asks the UI hierarchy to paint the component.

Generally, the UI delegate first checks whether the component is opaque and, if so, paints the entire background of the component. Then the UI delegate performs any look-and-feel-specific painting.

Lesson: Using Swing Components (The Java™ Tutorials > Creating a GUI With JFC/Swing)

This means that if you extend JComponentyour component needs to paint its own background if it's opaque. It's an article in The Swing Connection that discusses in depth the intricacies of painting. Here is its GUI: Here is its containment how to write custom swing componets hierarchy The click container, JFramepaints itself. The content pane first paints its custom swing, which is a solid gray rectangle.

The JComponent Class

It then tells see more How to write custom swing componets hierarchy to paint itself. In most look and feels, the JPanel is opaque by default and the content pane's background rectangle write custom swing actually appear componets hierarchy the finished GUI, being completely obscured by the JPanel.

It's important that the content pane be opaque.

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