GridBagLayout is one of the most flexible — and complex — layout managers the Java platform provides. A GridBagLayout places components in a grid of rows. Following is the declaration for gLayout class − public class GridBagLayout extends Object implements LayoutManager2, Serializable. Component; import ner; import gConstraints; import gLayout; import ; import JButton.
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Imagine your frame to be something like Excelthe gridx works as the Row variable, and gridy works as the Column variable. The new horizontal space is split evenly among all the columns.
GridBagLayout does not allow components to jaa multiple rows unless the component is in the leftmost column or you have specified positive gridx and gridy values for the component.
How to Use GridBagLayout
We then add the topRow as a whole to the application, with a grid width of 4. They can also be set to fill or expand their size in either dimension. Generally weights are specified with 0.
This is a very good practice that can save memory, which is a really important thing in very large apps that should be able of running in even mediocre PC’s. Resizable components positioned on the baseline with a baseline-resize behavior of OTHER are only resized if the baseline at the resized size fits within the display area.
If columnWeights has more elements than the number of columns, the excess elements are ignored – they do not cause more columns to be created. If the baseline is such that it does not fit within the display area the component is not resized. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more. 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.
Values that are different from those in the previous table entry are marked in italics. To place a component to the right of the previous one, set gridx to RELATIVE and use the same value for gridy that you used for the previous component.
Controls padding between the component and neighboring components. The Tutorial’s examples used to specify the constraints object a different way, which you might see in other programs as well.
How to Write a Container Listener. Values that are different from those in the previous table entry are marked in italics.
GridBagLayout – Learning Java, 4th Edition [Book]
This method is obsolete and supplied for backwards compatability only; new code should call getLayoutInfo instead.
How to Use GridLayout. Next, GridBagLayout considers the components that occupy more than gridbagalyout cell and things get a little weird. One of the most important features of GridBaglayout is that it lets you create arrangements in which components span two or more rows or columns.
We recommend specifying the gridx and gridy values for each component; this tends to result in more predictable layouts. Before calling addGBwe set any fields of gbc for which the defaults are inappropriate. Similarly if you gidbaglayout positioned a component relative to the baseline and none of the components in the row have a valid baseline the component is vertically gridbqglayout.
Note that if you enlarge the window, the last row is the only one that gets taller. Unless you specify at least one nonzero value for weightx or weightyall the components clump together in the center of their container.
Learning Java, 4th Edition by Daniel Leuck, Patrick Niemeyer
Each button is displayed at gridgaglayout preferred size, without stretching to fill the available space. This layout consists of three components: This method is obsolete and supplied for backwards compatability only; new code should call getMinSize instead.
GridBagLayout doesn’t allow components to span multiple rows unless the component is in the leftmost column or you’ve specified positive gridx and gridy values for the component. Dimension maximumLayoutSize Container target Returns the maximum dimensions for this layout given the components in the specified target container. To put space between buttons 4 and 5, we used insets to add a minimum of 10 pixels above button 5, and we made button 5 hug the south edge of its cell.
You might want to create a helper method that sets the constraints appropriately, gridbalayout adds the component with its gridbaglaoyut to the layout.
A panel that starts in row 0 and ends in row 1. Retrieves the constraints for the specified component.
Finally, there’s one other important function, fill. The preferred approach to set constraints on a component is to use the Container. Specifying Constraints The following code is typical of gridbahlayout goes in a container that uses a GridBagLayout.
How to Use GridBagLayout
Its code is in GridBagLayoutDemo. The button in the second row spans all the columns; the button in the third row spans the two right columns.
So now that we have our container with our layout, we need to create our GridBagConstraints. This is how jaa anchor will be positioned in the JFrame. Values that aren’t the default gridbagoayout marked in boldface. For horizontal left-to-right orientations, grid coordinate 0,0 is in the upper left corner of the container with x increasing to the right and y increasing downward.
Dimension preferredLayoutSize Container parent Determines the preferred size of the parent container using this grid bag layout. This behavior is also specified by the program.
We said earlier that three layout managers are in our user interface: Mava can set the following GridBagConstraints instance variables:. This lesson covers writing layout code by hand, which can be challenging. We place this button in cell 1,1so it occupies that cell and its neighbor, 2,1.