layout
Class TableLayout

java.lang.Object
  |
  +--layout.TableLayout

All Implemented Interfaces:

java.awt.LayoutManager, java.awt.LayoutManager2, java.io.Serializable, TableLayoutConstants

public class TableLayout

extends java.lang.Object

implements java.awt.LayoutManager2, java.io.Serializable, TableLayoutConstants

TableLayout is a layout manager that arranges components in rows and columns like a spreadsheet. TableLayout allows each row or column to be a different size. A row or column can be given an absolute size in pixels, a percentage of the available space, or it can grow and shrink to fill the remaining space after other rows and columns have been resized.

Using spreadsheet terminology, a cell is the intersection of a row and column. Cells have finite, non-negative sizes measured in pixels. The dimensions of a cell depend solely upon the dimensions of its row and column.

A component occupies a rectangular group of one or more cells. If the component occupies more than one cell, the component is resized to fit perfectly in the rectangular region of cells. If the component occupies a single cell, it can be aligned in four ways within that cell.

A single cell component can be stretched horizontally to fit the cell (full justification), or it can be placed in the center of the cell. The component could also be left justified or right justified. Similarly, the component can be full, center, top, or bottom justified in the vertical.

 public static void main (String args[])
 {
     // Create a frame
     Frame frame = new Frame("Example of TableLayout");
     frame.setBounds (100, 100, 300, 300);
 
     // Create a TableLayout for the frame
     double border = 10;
     double size[][] =
         {{border, 0.10, 20, TableLayout.FILL, 20, 0.20, border},  // Columns
          {border, 0.20, 20, TableLayout.FILL, 20, 0.20, border}}; // Rows
 
     frame.setLayout (new TableLayout(size));
 
     // Create some buttons
     String label[] = {"Top", "Bottom", "Left", "Right", "Center", "Overlap"};
     Button button[] = new Button[label.length];
 
     for (int i = 0; i < label.length; i++)
         button[i] = new Button(label[i]);
 
     // Add buttons
     frame.add (button[0], "1, 1, 5, 1"); // Top
     frame.add (button[1], "1, 5, 5, 5"); // Bottom
     frame.add (button[2], "1, 3      "); // Left
     frame.add (button[3], "5, 3      "); // Right
     frame.add (button[4], "3, 3, c, c"); // Center
     frame.add (button[5], "3, 3, 3, 5"); // Overlap
 
     // Allow user to close the window to terminate the program
     frame.addWindowListener
         (new WindowListener()
             {
                 public void windowClosing (WindowEvent e)
                 {
                     System.exit (0);
                 }
 
                 public void windowOpened (WindowEvent e) {}
                 public void windowClosed (WindowEvent e) {}
                 public void windowIconified (WindowEvent e) {}
                 public void windowDeiconified (WindowEvent e) {}
                 public void windowActivated (WindowEvent e) {}
                 public void windowDeactivated (WindowEvent e) {}
             }
         );
 
     // Show frame
     frame.show();
 }
 

See Also:

Serialized Form

Inner Class Summary

protected class

TableLayout.Entry

Field Summary

protected int[]	columnOffset Offsets of columns in pixels.
protected int[]	columnSize Widths of columns in pixels
protected double[]	columnSpec Widths of columns expressed in absolute and relative terms
protected static double[][]	defaultSize Default row/column size
protected boolean	dirty Indicates whether or not the size of the cells are known for the last known size of the container.
protected java.util.LinkedList	list List of components and their sizes
protected int	oldHeight Previous known height of the container
protected int	oldWidth Previous known width of the container
protected int[]	rowOffset Offsets of rows in pixels.
protected int[]	rowSize Heights of rows in pixels
protected double[]	rowSpec Heights of rows expressed in absolute and relative terms

Fields inherited from interface layout.TableLayoutConstants

BOTTOM, CENTER, FILL, FULL, LEFT, MAX_ALIGN, MIN_ALIGN, MINIMUM, PREFERRED, RIGHT, TOP

Constructor Summary

TableLayout()
Constructs an instance of TableLayout.

TableLayout(double[][] size)
Constructs an instance of TableLayout.

Method Summary

void	addLayoutComponent(java.awt.Component component, java.lang.Object constraint) Adds the specified component with the specified name to the layout.
void	addLayoutComponent(java.lang.String name, java.awt.Component component) Adds the specified component with the specified name to the layout.
protected void	calculateSize(java.awt.Container container) Calculates the sizes of the rows and columns based on the absolute and relative sizes specified in rowSpec and columnSpec and the size of the container.
void	deleteColumn(int i) Deletes a column in this layout.
void	deleteRow(int i) Deletes a row in this layout.
void	drawGrid(java.awt.Container container, java.awt.Graphics g) Draws a grid on the given container.
double[]	getColumn() Gets the sizes of columns in this layout.
double	getColumn(int i) Gets the width of a single column in this layout.
TableLayoutConstraints	getConstraints(java.awt.Component component) Gets the constraints of a given component.
float	getLayoutAlignmentX(java.awt.Container parent) Returns the alignment along the x axis.
float	getLayoutAlignmentY(java.awt.Container parent) Returns the alignment along the y axis.
int	getNumColumn() Gets the number of columns in this layout.
int	getNumRow() Gets the number of rows in this layout.
double[]	getRow() Gets the height of a single row in this layout.
double	getRow(int i) Gets the sizes of a row in this layout.
boolean	hidden() Determines whether or not there are any hidden components.
void	insertColumn(int i, double size) Inserts a column in this layout.
void	insertRow(int i, double size) Inserts a row in this layout.
void	invalidateLayout(java.awt.Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
void	layoutContainer(java.awt.Container container) To lay out the specified container using this layout.
java.awt.Dimension	maximumLayoutSize(java.awt.Container target) Returns the maximum dimensions for this layout given the components in the specified target container.
java.awt.Dimension	minimumLayoutSize(java.awt.Container container) Determines the minimum size of the container argument using this layout.
boolean	overlapping() Determines whether or not there are any overlapping components.
java.awt.Dimension	preferredLayoutSize(java.awt.Container container) Determines the preferred size of the container argument using this layout.
void	removeLayoutComponent(java.awt.Component component) Removes the specified component from the layout.
void	setColumn(double[] column) Adjusts the number and sizes of rows in this layout.
void	setColumn(int i, double size) Adjusts the width of a single column in this layout.
void	setConstraints(java.awt.Component component, TableLayoutConstraints constraint) Sets the constraints of a given component.
void	setRow(double[] row) Adjusts the number and sizes of rows in this layout.
void	setRow(int i, double size) Adjusts the height of a single row in this layout.
java.lang.String	toString() Converts this TableLayout to a string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

defaultSize

protected static final double[][] defaultSize

Default row/column size

columnSpec

protected double[] columnSpec

Widths of columns expressed in absolute and relative terms

rowSpec

protected double[] rowSpec

Heights of rows expressed in absolute and relative terms

columnSize

protected int[] columnSize

Widths of columns in pixels

rowSize

protected int[] rowSize

Heights of rows in pixels

columnOffset

protected int[] columnOffset

Offsets of columns in pixels. The left boarder of column n is at columnOffset[n] and the right boarder is at columnOffset[n + 1] for all columns including the last one. columnOffset.length = columnSize.length + 1

rowOffset

protected int[] rowOffset

Offsets of rows in pixels. The left boarder of row n is at rowOffset[n] and the right boarder is at rowOffset[n + 1] for all rows including the last one. rowOffset.length = rowSize.length + 1

list

protected java.util.LinkedList list

List of components and their sizes

dirty

protected boolean dirty

Indicates whether or not the size of the cells are known for the last known size of the container. If dirty is true or the container has been resized, the cell sizes must be recalculated using calculateSize.

oldWidth

protected int oldWidth

Previous known width of the container

oldHeight

protected int oldHeight

Previous known height of the container

Constructor Detail

TableLayout

public TableLayout()

Constructs an instance of TableLayout. This TableLayout will have one row and one column.

TableLayout

public TableLayout(double[][] size)

Constructs an instance of TableLayout.

Parameters:

size - widths of columns and heights of rows in the format, {{col0, col1, col2, ..., colN}, {row0, row1, row2, ..., rowM}} If this parameter is invalid, the TableLayout will have exactly one row and one column.

Method Detail

getConstraints

public TableLayoutConstraints getConstraints(java.awt.Component component)

Gets the constraints of a given component.

Parameters:

component - desired component

Returns:

If the given component is found, the constraints associated with that component. If the given component is null or is not found, null is returned.

setConstraints

public void setConstraints(java.awt.Component component,
                           TableLayoutConstraints constraint)

Sets the constraints of a given component.

Parameters:

component - desired component. This parameter cannot be null.

constraint - new set of constraints. This parameter cannot be null.

Returns:

If the given component is found, the constraints associated with that component. If the given component is null or is not found, null is returned.

setColumn

public void setColumn(double[] column)

Adjusts the number and sizes of rows in this layout. After calling this method, the caller should request this layout manager to perform the layout. This can be done with the following code:

     layout.layoutContainer(container);
     container.repaint();
 

or

     window.pack()
 

If this is not done, the changes in the layout will not be seen until the container is resized.

Parameters:

column - heights of each of the columns

See Also:

getColumn

setRow

public void setRow(double[] row)

Adjusts the number and sizes of rows in this layout. After calling this method, the caller should request this layout manager to perform the layout. This can be done with the following code: layout.layoutContainer(container); container.repaint(); or

     window.pack()
 

If this is not done, the changes in the layout will not be seen until the container is resized.

Parameters:

row - widths of each of the rows. This parameter cannot be null.

See Also:

getRow

setColumn

public void setColumn(int i,
                      double size)

Adjusts the width of a single column in this layout. After calling this method, the caller should request this layout manager to perform the layout. This can be done with the following code: layout.layoutContainer(container); container.repaint(); or

     window.pack()
 

If this is not done, the changes in the layout will not be seen until the container is resized.

Parameters:

i - zero-based index of column to set. If this parameter is not valid, an ArrayOutOfBoundsException will be thrown.

size - width of the column. This parameter cannot be null.

See Also:

getColumn

setRow

public void setRow(int i,
                   double size)

Adjusts the height of a single row in this layout. After calling this method, the caller should request this layout manager to perform the layout. This can be done with the following code: layout.layoutContainer(container); container.repaint(); or

     window.pack()
 

If this is not done, the changes in the layout will not be seen until the container is resized.

Parameters:

i - zero-based index of row to set. If this parameter is not valid, an ArrayOutOfBoundsException will be thrown.

size - height of the row. This parameter cannot be null.

See Also:

getRow

getColumn

public double[] getColumn()

Gets the sizes of columns in this layout.

Returns:

widths of each of the columns

See Also:

setColumn

getRow

public double[] getRow()

Gets the height of a single row in this layout.

Returns:

height of the requested row

See Also:

setRow

getColumn

public double getColumn(int i)

Gets the width of a single column in this layout.

Parameters:

i - zero-based index of row to get. If this parameter is not valid, an ArrayOutOfBoundsException will be thrown.

Returns:

width of the requested column

See Also:

setRow

getRow

public double getRow(int i)

Gets the sizes of a row in this layout.

Parameters:

i - zero-based index of row to get. If this parameter is not valid, an ArrayOutOfBoundsException will be thrown.

Returns:

height of each of the requested row

See Also:

setRow

getNumColumn

public int getNumColumn()

Gets the number of columns in this layout.

Returns:

the number of columns

getNumRow

public int getNumRow()

Gets the number of rows in this layout.

Returns:

the number of rows

insertColumn

public void insertColumn(int i,
                         double size)

Inserts a column in this layout. All components to the right of the insertion point are moved right one column. The container will need to be laid out after this method returns. See setColumn.

Parameters:

i - zero-based index at which to insert the column.

size - size of the column to be inserted

See Also:

setColumn, deleteColumn

insertRow

public void insertRow(int i,
                      double size)

Inserts a row in this layout. All components below the insertion point are moved down one row. The container will need to be laid out after this method returns. See setRow.

Parameters:

i - zero-based index at which to insert the column.

size - size of the row to be inserted

See Also:

setRow, deleteRow

deleteColumn

public void deleteColumn(int i)

Deletes a column in this layout. All components to the right of the deletion point are moved left one column. The container will need to be laid out after this method returns. See setColumn.

Parameters:

i - zero-based index of column to delete

See Also:

setColumn, deleteColumn

deleteRow

public void deleteRow(int i)

Deletes a row in this layout. All components below the deletion point are moved up one row. The container will need to be laid out after this method returns. See setRow. There must be at least two rows in order to delete a row.

Parameters:

i - zero-based index of column to delete

See Also:

setRow, deleteRow

toString

public java.lang.String toString()

Converts this TableLayout to a string.

Overrides:

toString in class java.lang.Object

Returns:

a string representing the columns and row sizes in the form "{{col0, col1, col2, ..., colN}, {row0, row1, row2, ..., rowM}}"

drawGrid

public void drawGrid(java.awt.Container container,
                     java.awt.Graphics g)

Draws a grid on the given container. This is useful for seeing where the rows and columns go. In the container's paint method, call this method.

Parameters:

container - container using this TableLayout

g - graphics content of container (can be offscreen)

hidden

public boolean hidden()

Determines whether or not there are any hidden components. A hidden component is one that will not be shown with this layout's current configuration. Such a component is, at least partly, in an invalid row or column. For example, on a table with five rows, row -1 and row 5 are both invalid. Valid rows are 0 through 4, inclusively.

Returns:

True, if there are any hidden components. False, otherwise.

See Also:

overlapping

overlapping

public boolean overlapping()

Determines whether or not there are any overlapping components. Two components overlap if they cover at least one common cell.

Returns:

True, if there are any overlapping components. False, otherwise.

See Also:

hidden

calculateSize

protected void calculateSize(java.awt.Container container)

Calculates the sizes of the rows and columns based on the absolute and relative sizes specified in rowSpec and columnSpec and the size of the container. The result is stored in rowSize and columnSize.

Parameters:

container - container using this TableLayout

layoutContainer

public void layoutContainer(java.awt.Container container)

To lay out the specified container using this layout. This method reshapes the components in the specified target container in order to satisfy the constraints of all components.

User code should not have to call this method directly.

Specified by:

layoutContainer in interface java.awt.LayoutManager

Parameters:

container - container being served by this layout manager

preferredLayoutSize

public java.awt.Dimension preferredLayoutSize(java.awt.Container container)

Determines the preferred size of the container argument using this layout. The preferred size is the smallest size that, if used for the container's size, will ensure that all components are at least as large as their preferred size. This method cannot guarantee that all components will be their preferred size. For example, if component A and component B are each allocate half of the container's width and component A wants to be 10 pixels wide while component B wants to be 100 pixels wide, they cannot both be accommodated. Since in general components rather be larger than their preferred size instead of smaller, component B's request will be fulfilled. The preferred size of the container would be 200 pixels.

Specified by:

preferredLayoutSize in interface java.awt.LayoutManager

Parameters:

container - container being served by this layout manager

Returns:

a dimension indicating the container's preferred size

minimumLayoutSize

public java.awt.Dimension minimumLayoutSize(java.awt.Container container)

Determines the minimum size of the container argument using this layout. The minimum size is the smallest size that, if used for the container's size, will ensure that all components are at least as large as their minimum size. This method cannot guarantee that all components will be their minimum size. For example, if component A and component B are each allocate half of the container's width and component A wants to be 10 pixels wide while component B wants to be 100 pixels wide, they cannot both be accommodated. Since in general components rather be larger than their minimum size instead of smaller, component B's request will be fulfilled. The minimum size of the container would be 200 pixels.

Specified by:

minimumLayoutSize in interface java.awt.LayoutManager

Parameters:

container - container being served by this layout manager

Returns:

a dimension indicating the container's minimum size

addLayoutComponent

public void addLayoutComponent(java.lang.String name,
                               java.awt.Component component)

Adds the specified component with the specified name to the layout.

Specified by:

addLayoutComponent in interface java.awt.LayoutManager

Parameters:

name - indicates entry's position and anchor

component - component to add

addLayoutComponent

public void addLayoutComponent(java.awt.Component component,
                               java.lang.Object constraint)

Adds the specified component with the specified name to the layout.

Specified by:

addLayoutComponent in interface java.awt.LayoutManager2

Parameters:

component - component to add

constraint - indicates entry's position and alignment

removeLayoutComponent

public void removeLayoutComponent(java.awt.Component component)

Removes the specified component from the layout.

Specified by:

removeLayoutComponent in interface java.awt.LayoutManager

Parameters:

component - component being removed

maximumLayoutSize

public java.awt.Dimension maximumLayoutSize(java.awt.Container target)

Returns the maximum dimensions for this layout given the components in the specified target container.

Specified by:

maximumLayoutSize in interface java.awt.LayoutManager2

Parameters:

target - the component which needs to be laid out

Returns:

unconditionally, a Dimension of Integer.MAX_VALUE by Integer.MAX_VALUE since TableLayout does not limit the maximum size of a container

getLayoutAlignmentX

public float getLayoutAlignmentX(java.awt.Container parent)

Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

Specified by:

getLayoutAlignmentX in interface java.awt.LayoutManager2

Returns:

unconditionally, 0.5

getLayoutAlignmentY

public float getLayoutAlignmentY(java.awt.Container parent)

Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

Specified by:

getLayoutAlignmentY in interface java.awt.LayoutManager2

Returns:

unconditionally, 0.5

invalidateLayout

public void invalidateLayout(java.awt.Container target)

Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.

Specified by:

invalidateLayout in interface java.awt.LayoutManager2