Create User Interfaces - JavaFX: Developing Rich Internet Applications - page 115

translateY: bind (scene.height -
rect.layoutBounds.height)/2,0 -
rect.layoutBounds.minY
...
}
}
}
Notice that we need to assign local variables to both the Scene and the Rectangle,
and then use those variables within a bind to set the translateX and translateY
variables. Also, notice that we need to include the minX/minY for each, as this
would include any offset due to shape drawing, effects, and clipping.
Custom Layout
If you need more control over layouts, you need to create a custom layout using
the javafx.scene.layout.Container class. To illustrate this, we will walk
through a GridLayout class. The GridLayout class lays out its nodes in a series
of rows and columns. Instead of using a fixed width and height for the rows and
columns, this layout class calculates the width of each column to be wide enough
to handle the widest node within the column. Likewise, the height for each row is
calculated to handle the maximum height to accommodate each node in that row.
Therefore, the column widths and row heights vary depending on the nodes con-
tained in each.
Because some nodes will have extra horizontal or vertical space within a row or
column, you can specify the alignment of those nodes within the row or column.
Either align left, right, or center for columns, and align top, center, or bottom
within rows. The actual alignment values are directional with values for North,
NorthEast, East, and so on.
To begin, we create the GridLayout class extending javafx.scene.layout
.Container .
public class GridLayout extends Container {
javafx.scene.layout.Container extends javafx.scene.Group , so from there
we have access to the content[] sequence of Nodes. Also, Container extends
javafx.scene.layout.Resizable , and from there we have access to width ,
height , minimum width / height , maximum width / height , and preferred width /
height . There are also some helper functions defined in Resizable ; we will use
getNodePreferredWidth/Height() .