TableLayoutConstraints

The preceeding examples have expressed the layout constraints in terms of a simple string. This is a convenient short-hand notation, but it is not the only way to express constraints. The TableLayoutConstraints class provides a means of manipulating constraints as objects. The following three blocks of code are equivalent.

container.add (firstComponent, "1, 2, R, B");
container.add (secondComponent, "5, 8, 6, 10");
                      

container.add (firstComponent,
    new TableLayoutConstraints(1, 2, 1, 2, TableLayout.RIGHT, TableLayout.BOTTOM));

container.add (secondComponent,
    new TableLayoutConstraints(5, 8, 6, 10, TableLayout.FULL, TableLayout.FULL));
                      

TableLayoutConstraints c = new TableLayoutConstraints();

c.col1 = c.col2 = 1;
c.row1 = c.row2 = 2;
c.hAlign = TableLayout.RIGHT;
c.vAlign = TableLayout.BOTTOM;

container.add (firstComponent, c);

c.col1 = 5;
c.col2 = 6;
c.row1 = 8;
c.row2 = 10;

container.add (secondComponent, c);
                      

There are two constructors for TableLayoutConstraints. One takes no parameters and defaults to the short-hand "0, 0" or occupy a single cell at (0, 0) with full horizontal and vertical justification. The second constructor takes six parameters: col1, row1, col2, row2, hAlign, and vAlign. The first pair is the upper-left corner of the cell set. The second pair is the lower-right corner. If the first and second pair match, the constraint refers to a single cell and the third pair is used for justification.

Since the fields of TableLayoutConstraints are public, they may be manipulated directly. This was done for convenience. The third example shows the fields being manipulated to set constraints. Since TableLayout will make a copy of the TableLayoutConstraints, you can use the same constraints object when setting the constraints for more than one component.

TableLayout has two methods pertaining to TableLayoutConstraints.

getContstraints(Component)

setConstraints(Component, TableLayoutConstraints)