![]() ![]() Similarly, the height of the component will be at least its minimum height plus ipady*2 pixels. The width of the component will be at least its minimum width plus ipadx*2 pixels, since the padding applies to both sides of the component. ipadx, ipady Specifies the internal padding: how much to add to the size of the component. Valid values (defined as GridBagConstraints constants) include NONE (the default), HORIZONTAL (make the component wide enough to fill its display area horizontally, but do not change its height), VERTICAL (make the component tall enough to fill its display area vertically, but do not change its width), and BOTH (make the component fill its display area entirely). fill Used when the component's display area is larger than the component's requested size to determine whether and how to resize the component. Note: GridBagLayout does not allow components to span multiple rows unless the component is in the leftmost column or you have specified positive gridx and gridy values for the component. We recommend specifying the gridwidth and gridheight values for each component rather than just using GridBagConstraints.RELATIVE and GridBagConstraints.REMAINDER this tends to result in more predictable layouts. Use GridBagConstraints.RELATIVE to specify that the component be the next to last one in its row (for gridwidth) or column (for gridheight). Use GridBagConstraints.REMAINDER to specify that the component be the last one in its row (for gridwidth) or column (for gridheight). ![]() These constraints specify the number of cells the component uses, not the number of pixels it uses. gridwidth, gridheight Specify the number of columns (for gridwidth) or rows (for gridheight) in the component's display area. We recommend specifying the gridx and gridy values for each component rather than just using GridBagConstraints.RELATIVE this tends to result in more predictable layouts. Use GridBagConstraints.RELATIVE (the default value) to specify that the component be placed just to the right of (for gridx) or just below (for gridy) the component that was added to the container just before this component was added. The leftmost column has address gridx=0 and the top row has address gridy=0. GridBagConstraints instance variables: gridx, gridy Specify the row and column at the upper left of the component. Note: The following discussion assumes that the GridBagLayout controls a container that has a left-to-right component orientation. You will see a more detailed example in the next section. The following code is typical of what goes in a container that uses a The following sections explain the constraints you can set and provide examples. The preferred approach to set constraints on a component is to use the Container.add variant, passing it a GridBagConstraints object, as demonstrated in the next sections. ![]() The way the program specifies the size and position characteristics of its components is by specifying constraints for each component. This behavior is also specified by the program. You will also notice that each component takes up all the available horizontal space but not (as you can see with button 5) all the available vertical space. This resizing behavior is based on weights the program assigns to individual components in the GridBagLayout. The new horizontal space is split evenly among all the columns. If you enlarge the window as shown in the following figure, you will notice that the bottom row, which contains Button 5, gets all the new vertical space. The button in the second row spans all the columns the button in the third row spans the two right columns. As you can see, the grid has three rows and three columns. ![]() The following figure shows the grid for the preceding applet. Essentially, GridBagLayout places components in rectangles (cells) in a grid, and then uses the components' preferred sizes to determine how big the cells should be. Similarly, not all columns necessarily have the same width. Not all rows necessarily have the same height. A GridBagLayout places components in a grid of rows and columns, allowing specified components to span multiple rows or columns. GridBagLayout is one of the most flexible and complex layout managers the Java platform provides. Alternatively, to compile and run the example yourself, consult the example index. Java™ Web Start ( download JDK 7 or later). Here is a picture of an example that usesĬlick the Launch button to run GridBagLayoutDemo using If you are interested in using JavaFX to create your GUI, see Otherwise, if you want to code by hand and do not want to use GroupLayout, then GridBagLayout is recommended as the next most flexible and powerful layout manager. If you are not interested in learning all the details of layout management, you might prefer to use the GroupLayout layout manager combined with a builder tool to lay out your GUI. Note: This lesson covers writing layout code by hand, which can be challenging. ![]()
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