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Overview

TableLayout is a lightweight Java library for setting the position and size of UI widgets using a logical table, similar to HTML tables. The core of TableLayout is UI toolkit agnostic and comes with support for Swing, Android, and TWL. Layout using tables is intuitive and TableLayout's Java API is very easy to use.

A fork of TableLayout is included inside libgdx, so TableLayout is not needed if using libgdx.

Quickstart
Root table
Debugging
Adding cells
Logical table
Cell properties
- Expand
- Alignment
- Fill
- Widget size
- Padding
- Spacing
- Colspan
Uniform
Defaults
Stacks
Android
Similar libraries

Quickstart

Here is a quick example of a simple form in libgdx:

    // Keep your code clean by creating widgets separate from layout.
    Label nameLabel = new Label("Name:", skin);
    TextField nameText = new TextField(skin);
    Label addressLabel = new Label("Address:", skin);
    TextField addressText = new TextField(skin);

    Table table = new Table();
    table.add(nameLabel);              // Row 0, column 0.
    table.add(nameText).width(100);    // Row 0, column 1.
    table.row();                       // Move to next row.
    table.add(addressLabel);           // Row 1, column 0.
    table.add(addressText).width(100); // Row 1, column 1.

This code adds 4 cells to the table which are arranged in two columns and two rows. The add method returns a Cell, which has methods to control layout. Here the width of the text fields are set to 100.

The example code used in this documentation is for libgdx, but the API for the other supported toolkits is almost identical.

Root table

When doing UI layout, a UI widget does not set its own size. Instead, it provides a minimum, preferred, and maximum size. The widget's parent uses its own size along with these hints to size the widget. Many layouts will use a single table at the root which has a fixed size, often the whole screen. Widgets and nested tables are added to the root table.

Sizing the root table varies in each UI toolkit. Eg, in Swing you would likely add the table to the JFrame's content pane. In libgdx the setFillParent method can be used:

    Table table = new Table();
    table.setFillParent(true);
    stage.addActor(table);

Debugging

TableLayout can draw debug lines to visualize what is happening in the layout. Debugging is enabled by calling debug on the table. libgdx automatically renders debug lines if they are enabled. Other UI toolkits may require a method to be called to render the lines.

    table.debug();      // Turn on all debug lines (table, cell, and widget).
    table.debugTable(); // Turn on only table lines.

Adding cells

Widgets are added to a table with the add method (for UI toolkits that already have an add method, addCell is used). This adds a cell to the current row. To move to the next row, call the row method.

    table.add(nameLabel);    // Row 0, column 0.
    table.add(nameText);     // Row 0, column 1. 
    table.row();             // Move to next row.
    table.add(addressLabel); // Row 1, column 0.
    table.add(addressText);  // Row 1, column 1.

The add method returns a Cell, which has properties that control the layout. Every method on the cell returns the cell, allowing calls to be chained.

    table.add(nameText).padLeft(10).width(100); // Sets left padding and width on the new cell.

Logical table

The cells make up a logical table, but it is not sized to the table widget.

The outer blue rectangle shows the size of the table widget. The inner blue rectangle shows the size of the logical table, which is aligned to center by default. The alignment can be changed using methods on the table. The table methods return the table, so can be chained just like the cell methods.

    table.right().bottom();

Cell properties

Expand

To make the logical table take up the entire size of the table widget, TableLayout needs to be told which cells will receive the extra space.

    table.add(nameLabel).expandX(); // Column 0 receives all extra horizontal space.
    table.add(nameText).width(100);
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100);

The red lines show the cell bounds and the green lines show the widget bounds. Note that the left column has received all of the extra space in the x direction. Only one cell needs to have expand to cause the entire column or row to expand. If multiple columns expand, the extra space is distributed evenly.

    table.add(nameLabel).expandX();           // Receives extra horizontal space.
    table.add(nameText).width(100).expandX(); // Also receives extra horizontal space.
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100);

Expand also works in the y direction via the expandY method. The expand method causes expand to happen in both directions.

    table.add(nameLabel).expand();     // Receives all extra horizontal and vertical space.
    table.add(nameText).width(100);
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100);

Alignment

Similar to aligning the logical table, a widget can be aligned inside the cell.

    table.add(nameLabel).expand().bottom().right(); // Aligned bottom right.
    table.add(nameText).width(100).top();           // Aligned top.
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100);

Fill

The fill method causes a widget to be sized to the cell. Like expand, there are also fillX and fillY methods.

    table.add(nameLabel).expand().bottom().fillX(); // Sized to cell horizontally.
    table.add(nameText).width(100).top();
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100);

Note the red cell lines are drawn on top of the green widget lines.

Widget size

By default, the table attempts to size widgets to their preferred size. If the widgets don't fit, they are sized between their preferred size and their minimum size, with widgets that have a larger preferred size receiving more space. If the widgets don't fit at their minimum size then the layout is broken and widgets may overlap. The fill methods won't make a widget larger than the widget's maximum size.

Widgets should not be subclassed to change the preferred, minimum, or maximum size. Instead, these sizes can be set on the cell and will be used instead of the widget's value.

    table.add(nameLabel);
    table.add(nameText).minWidth(100);     // Sets min width.
    table.row();
    table.add(addressLabel);
    table.add(addressText).prefWidth(999); // Sets pref width.

Here the prefWidth of 999 is larger than the table, so it is sized down to fit.

width is a shortcut method for setting minWidth, prefWidth, and maxWidth to the same value. height is a shortcut method for setting minHeight, prefHeight, and maxHeight to the same value. The size method takes a width and a height and sets all six properties.

Padding

Padding is extra space around the edges of a cell.

    table.add(nameLabel);
    table.add(nameText).width(100).padBottom(10); // Sets bottom padding.
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100).pad(10);    // Sets top, left, bottom, right padding.

Note that padding between cells combines, so there are 20 pixels between the text fields. The debug lines don't necessarily show which cell the padding comes from, since it is not important for the layout of the table.

Padding can also be applied to the edges of the table.

    table.pad(10);

Spacing

Like padding, spacing is extra space around the edges of a cell. However, spacing between cells does not combine, instead the larger of the two is used. Also, spacing is not applied at the edge of the table. Spacing makes it easy to have consistent space between cells.

    table.add(nameLabel);
    table.add(nameText).width(100).spaceBottom(10); // Sets bottom spacing.
    table.row();
    table.add(addressLabel);
    table.add(addressText).width(100).space(10);    // Sets top, left, bottom, right spacing.

Note that the spacing between cells doesn't combine, so there are 10 pixels between the text fields. Also

Tablelayout

Install / Use

README