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Chapter 18 The java.awt Package |
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Chapter 18 The java.awt Package |
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This class implements the LayoutManager interface to lay out Component objects in a Container. It is the most complicated and most powerful LayoutManager in the java.awt package. It divides the container into a grid of rows and columns (which need not have the same width and height) and places the components into this grid, adjusting the size of the grid cells as necessary to ensure that components do not overlap. Each component controls how it is positioned within this grid by specifying a number of variables (or "constraints") in a GridBagConstraints object. Do not confuse this class with the much simpler GridLayout which arranges components in a grid of equally sized cells.
Use setConstraints() to specify a GridBagConstraints object for each of the components in the container. Or, in Java 1.1, specify the GridBagConstraints object when adding the component to the container with add(). The variables in this object specify the position of the component in the grid, the number of horizontal and vertical grid cells that the component occupies, and also control other important aspects of component layout. See GridBagConstraints for more information on these "constraint" variables. setConstraints() makes a copy of the constraints object, so you may reuse a single object in your code.
Note that applications should never call the LayoutManager methods of this class directly; the Container for which the GridBagLayout is registered does this.
public class GridBagLayout extends Object implements LayoutManager2, Serializable {
// Public Constructor
public GridBagLayout();
// Constants
protected static final int MAXGRIDSIZE;
protected static final int MINSIZE;
protected static final int PREFERREDSIZE;
// Public Instance Variables
public double[] columnWeights;
public int[] columnWidths;
public int[] rowHeights;
public double[] rowWeights;
// Protected Instance Variables
protected Hashtable comptable;
protected GridBagConstraints defaultConstraints;
protected GridBagLayoutInfo layoutInfo;
// Public Instance Methods
public void addLayoutComponent(String name, Component comp); // From LayoutManager
1.1 public void addLayoutComponent(Component comp, Object constraints); // From LayoutManager2
public GridBagConstraints getConstraints(Component comp);
1.1 public float getLayoutAlignmentX(Container parent); // From LayoutManager2
1.1 public float getLayoutAlignmentY(Container parent); // From LayoutManager2
public int[][] getLayoutDimensions();
public Point getLayoutOrigin();
public double[][] getLayoutWeights();
1.1 public void invalidateLayout(Container target); // From LayoutManager2
public void layoutContainer(Container parent); // From LayoutManager
public Point location(int x, int y);
1.1 public Dimension maximumLayoutSize(Container target); // From LayoutManager2
public Dimension minimumLayoutSize(Container parent); // From LayoutManager
public Dimension preferredLayoutSize(Container parent); // From LayoutManager
public void removeLayoutComponent(Component comp); // From LayoutManager
public void setConstraints(Component comp, GridBagConstraints constraints);
public String toString(); // Overrides Object
// Protected Instance Methods
protected void AdjustForGravity(GridBagConstraints constraints, Rectangle r);
protected void ArrangeGrid(Container parent);
protected GridBagLayoutInfo GetLayoutInfo(Container parent, int sizeflag);
protected Dimension GetMinSize(Container parent, GridBagLayoutInfo info);
protected GridBagConstraints lookupConstraints(Component comp);
}
Object->GridBagLayout(LayoutManager2(LayoutManager), Serializable)
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| java.awt.GridBagConstraints (JDK 1.0) |  |
java.awt.GridLayout (JDK 1.0) |
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