What is panels in java

Opaque panels work well as content panes and can help with painting efficiently, as described in Using Top-Level Containers. You can change a panel's transparency by invoking the setOpaque method. A transparent panel draws no background, so that any components underneath show through. The following picture shows a colored version of the Converter application, which is discussed in more detail in Using Models. As the Converter example demonstrates, panels are useful for grouping components, simplifying component layout, and putting borders around groups of components.

The rest of this section gives hints on grouping and laying out components. For information about using borders, see How to Use Borders. Like other containers, a panel uses a layout manager to position and size its components. By default, a panel's layout manager is an instance of FlowLayout , which places the panel's contents in a row. You can easily make a panel use any other layout manager by invoking the setLayout method or by specifying a layout manager when creating the panel.

The latter approach is preferable for performance reasons, since it avoids the unnecessary creation of a FlowLayout object. This approach does not work with BoxLayout , since the BoxLayout constructor requires a pre-existing container. Here is an example that uses BoxLayout. When you add components to a panel, you use the add method. Add a comment. Active Oldest Votes. Improve this answer. Kai Kai Panels exist for a few reasons. Corey Noel Corey Noel 3 3 silver badges 7 7 bronze badges.

It allows you to group components together It allows you to devise complex interfaces, as each panel can have a different layout, allowing you to leverage the power of different layout managers. It allows you to build reusable components and isolate responsibility But most of all, it gives you the bases for deciding how the panel should be deployed. A panel also makes a good surface onto which to perform custom painting.

For all the benefits mentioned above - its isolated and reusable There are many other reasons for using panels, these are just a few that pop to mind. MadProgrammer MadProgrammer k 21 21 gold badges silver badges bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Related Articles. Table of Contents.

Save Article. Improve Article. Like Article. NORTH ;. Specifies the layout manager for the container. Updates the rendering of the container. After the panel has been created, other components can be added to Panel object by calling its add Component c method inherited from the Container class.

The following code fragment demonstrates creating a panel and adding two buttons to it. Using panels, you can design complex GUls. Dinesh Thakur is a Freelance Writer who helps different clients from all over the globe.