Package org.eclipse.jface.layout

Class GridLayoutFactory

java.lang.Object
org.eclipse.jface.layout.GridLayoutFactory
public final class GridLayoutFactory extends Object
GridLayoutFactory creates and initializes grid layouts. There are two ways to use GridLayoutFactory. Normally, it is used as a shorthand for writing "new GridLayout()" and initializing a bunch of fields. In this case the main benefit is a more concise syntax and the ability to create more than one identical GridLayout from the same factory. Changing a property of the factory will affect future layouts created by the factory, but has no effect on layouts that have already been created.

GridLayoutFactory can also generate grid data for all the controls in a layout. This is done with the generateLayout method. To use this feature:

  1. Create the composite
  2. Create all the controls in the composite
  3. Call generateLayout

The order here is important. generateLayout must be called after all the child controls have been created. generateLayout will not change any layout data that has already been attached to a child control and it will not recurse into nested composites.

Since:
3.2

  • Method Details

    • createFrom

      public static GridLayoutFactory createFrom(GridLayout l)
      Creates a factory that creates copies of the given layout.
      Parameters:
      l - layout to copy
      Returns:
      a new GridLayoutFactory instance that creates copies of the given layout

    • copy

      public GridLayoutFactory copy()
      Creates a copy of the receiver.
      Returns:
      a copy of the receiver

    • swtDefaults

      public static GridLayoutFactory swtDefaults()
      Creates a GridLayoutFactory that creates GridLayouts with the default SWT values.

      Initial values are:

      • numColumns(1)
      • margins(5,5)
      • extendedMargins(0,0,0,0)
      • spacing(5,5)
      • equalWidth(false)
      Returns:
      a GridLayoutFactory that creates GridLayouts as though created with their default constructor
      See Also:

    • fillDefaults

      public static GridLayoutFactory fillDefaults()
      Creates a GridLayoutFactory that creates GridLayouts with no margins and default dialog spacing.

      Initial values are:

      • numColumns(1)
      • margins(0,0)
      • extendedMargins(0,0,0,0)
      • spacing(LayoutConstants.getSpacing())
      • equalWidth(false)
      Returns:
      a GridLayoutFactory that creates GridLayouts as though created with their default constructor
      See Also:

    • equalWidth

      public GridLayoutFactory equalWidth(boolean equal)
      Sets whether the columns should be forced to be equal width
      Parameters:
      equal - true iff the columns should be forced to be equal width
      Returns:
      this

    • spacing

      public GridLayoutFactory spacing(int hSpacing, int vSpacing)
      Sets the spacing for layouts created with this factory. The spacing is the distance between cells within the layout.
      Parameters:
      hSpacing - horizontal spacing (pixels)
      vSpacing - vertical spacing (pixels)
      Returns:
      this
      See Also:

    • spacing

      public GridLayoutFactory spacing(Point spacing)
      Sets the spacing for layouts created with this factory. The spacing is the distance between cells within the layout.
      Parameters:
      spacing - space between controls in the layout (pixels)
      Returns:
      this
      See Also:

    • margins

      public GridLayoutFactory margins(Point margins)
      Sets the margins for layouts created with this factory. The margins are the distance between the outer cells and the edge of the layout.
      Parameters:
      margins - margin size (pixels)
      Returns:
      this
      See Also:

    • margins

      public GridLayoutFactory margins(int width, int height)
      Sets the margins for layouts created with this factory. The margins specify the number of pixels of horizontal and vertical margin that will be placed along the left/right and top/bottom edges of the layout. Note that these margins will be added to the ones specified by extendedMargins(int, int, int, int).
      Parameters:
      width - margin width (pixels)
      height - margin height (pixels)
      Returns:
      this
      See Also:

    • extendedMargins

      public GridLayoutFactory extendedMargins(int left, int right, int top, int bottom)
      Sets the margins for layouts created with this factory. The margins specify the number of pixels of horizontal and vertical margin that will be placed along the left, right, top, and bottom edges of the layout. Note that these margins will be added to the ones specified by margins(int, int).
      Parameters:
      left - left margin size (pixels)
      right - right margin size (pixels)
      top - top margin size (pixels)
      bottom - bottom margin size (pixels)
      Returns:
      this
      Since:
      3.3
      See Also:

    • extendedMargins

      public GridLayoutFactory extendedMargins(Rectangle differenceRect)
      Sets the margins for layouts created with this factory. The margins specify the number of pixels of horizontal and vertical margin that will be placed along the left, right, top, and bottom edges of the layout. Note that these margins will be added to the ones specified by margins(int, int). 
       
     // Construct a GridLayout whose left, right, top, and bottom
     // margin sizes are 10, 5, 0, and 15 respectively

     Rectangle margins = Geometry.createDiffRectangle(10,5,0,15);
     GridLayoutFactory.fillDefaults().extendedMargins(margins).applyTo(composite1);
      Parameters:
      differenceRect - rectangle which, when added to the client area of the layout, returns the outer area of the layout. The x and y values of the rectangle correspond to the position of the bounds of the layout with respect to the client area. They should be negative. The width and height correspond to the relative size of the bounds of the layout with respect to the client area, and should be positive.
      Returns:
      this
      Since:
      3.3
      See Also:

    • numColumns

      public GridLayoutFactory numColumns(int numColumns)
      Sets the number of columns in the layout
      Parameters:
      numColumns - number of columns in the layout
      Returns:
      this

    • create

      public GridLayout create()
      Creates a new GridLayout, and initializes it with values from the factory.
      Returns:
      a new initialized GridLayout.
      See Also:

    • applyTo

      public void applyTo(Composite c)
      Creates a new GridLayout and attaches it to the given composite. Does not create the GridData of any of the controls in the composite.
      Parameters:
      c - composite whose layout will be set
      See Also:

    • copyLayout

      public static GridLayout copyLayout(GridLayout l)
      Copies the given GridLayout instance
      Parameters:
      l - layout to copy
      Returns:
      a new GridLayout

    • generateLayout

      public void generateLayout(Composite c)
      Applies this layout to the given composite, and attaches default GridData to all immediate children that don't have one. The layout is generated using heuristics based on the widget types. In most cases, it will create exactly the same layout that would have been hardcoded by the programmer. In any situation where it does not produce the desired layout, the GridData for any child can be overridden by attaching the layout data before calling this method. In these cases, the special-case layout data can be hardcoded and the algorithm can supply defaults to the rest.

      This must be called AFTER all of the child controls have been created and their layouts attached. This method will attach a layout to the given composite. If any new children are created after calling this method, their GridData must be created manually. The algorithm does not recurse into child composites. To generate all the layouts in a widget hierarchy, the method must be called bottom-up for each Composite.

      All controls are made to span a single cell. The algorithm tries to classify controls into one of the following categories:

      • Pushbuttons: Set to a constant size large enough to fit their text and no smaller than the default button size.
      • Wrapping with text (labels, read-only text boxes, etc.): override the preferred horizontal size with the default wrapping point, fill horizontally, grab horizontal space, keep the preferred vertical size
      • Wrapping without text (toolbars, coolbars, etc.): fill align, don't grab, use the preferred size
      • Horizontally scrolling controls (anything with horizontal scrollbars or where the user edits text and can cursor through it from left-to-right): override the preferred horizontal size with a constant, grab horizontal, fill horizontal.
      • Vertically scrolling controls (anything with vertical scrollbars or where the user edits text and can cursor through it up and down): override the preferred vertical size with a constant, grab vertical, fill vertical
      • Nested layouts: fill align both directions, grab along any dimension if the layout would be able to expand along that dimension.
      • Non-wrapping non-scrollable read-only text: fill horizontally, center vertically, default size, don't grab
      • Non-wrapping non-scrollable non-text: fill both, default size, don't grab
      Parameters:
      c - composite whose layout will be generated

    • toString

      public String toString()
      Overrides:
      toString in class Object