GroupLayout (Codename One API)

java.lang.Object
- com.codename1.ui.layouts.Layout
- - com.codename1.ui.layouts.GroupLayout

public class GroupLayout
extends Layout

GroupLayout is a LayoutManager that hierarchically groups components to achieve common, and not so common, layouts. Grouping is done by instances of the Group class. GroupLayout supports two types of groups:

Sequential:	A sequential group positions its child elements sequentially, one after another.
Parallel:	A parallel group positions its child elements in the same space on top of each other. Parallel groups can also align the child elements along their baseline.

Each Group can contain any number of child groups, Components or gaps. GroupLayout treats each axis independently. That is, there is a group representing the horizontal axis, and a separate group representing the vertical axis. The horizontal group is responsible for setting the x and width of its contents, where as the vertical group is responsible for setting the y and height of its contents.

The following code builds a simple layout consisting of two labels in one column, followed by two textfields in the next column:

   Container panel = ...;
   GroupLayout layout = new GroupLayout(panel);
   panel.setLayout(layout);
   layout.setAutocreateGaps(true);
   layout.setAutocreateContainerGaps(true);
   GroupLayout.SequentialGroup hGroup = layout.createSequentialGroup();
   hGroup.add(layout.createParallelGroup().add(label1).add(label2)).
          add(layout.createParallelGroup().add(tf1).add(tf2));
   layout.setHorizontalGroup(hGroup);
   GroupLayout.SequentialGroup vGroup = layout.createSequentialGroup();
   vGroup.add(layout.createParallelGroup(GroupLayout.BASELINE).add(label1).add(tf1)).
          add(layout.createParallelGroup(GroupLayout.BASELINE).add(label2).add(tf2));
   layout.setVerticalGroup(vGroup);

This layout consists of the following:

The horizontal axis consists of a sequential group containing two parallel groups. The first parallel group consists of the labels, with the second parallel group consisting of the text fields.
The vertical axis similarly consists of a sequential group containing two parallel groups. The parallel groups align their contents along the baseline. The first parallel group consists of the first label and text field, and the second group consists of the second label and text field.

There are a couple of things to notice in this code:

You need not explicitly add the components to the container, this is indirectly done by using one of the add methods.
The various add methods of Groups return themselves. This allows for easy chaining of invocations. For example, group.add(label1).add(label2); is equivalent to group.add(label1);group.add(label2);.
There are no public constructors for the Groups, instead use the create methods of GroupLayout.

GroupLayout offer the ability to automatically insert the appropriate gap between components. This can be turned on using the setAutocreateGaps() method. Similarly you can use the setAutocreateContainerGaps() method to insert gaps between the components and the container.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`class`	`GroupLayout.Group` Group provides for commonality between the two types of operations supported by `GroupLayout`: laying out components one after another (`SequentialGroup`) or layout on top of each other (`ParallelGroup`).
`class`	`GroupLayout.ParallelGroup` A `Group` that lays out its elements on top of each other.
`class`	`GroupLayout.SequentialGroup` A `Group` that lays out its elements sequentially, one after another.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`BASELINE` Possible alignment type.
`static int`	`CENTER` Possible alignment type.
`static int`	`DEFAULT_SIZE` Possible value for the add methods that takes a Component.
`static int`	`EAST` Compass-direction east (right).
`static int`	`HORIZONTAL` Possible argument when linking sizes of components.
`static int`	`LEADING` Possible alignment type.
`static int`	`NORTH` Compass-direction North (up).
`static int`	`PREFERRED_SIZE` Possible value for the add methods that takes a Component.
`static int`	`SOUTH` Compass-direction south (down).
`static int`	`TRAILING` Possible alignment type.
`static int`	`VERTICAL` Possible argument when linking sizes of components.
`static int`	`WEST` Compass-direction west (left).

Constructor Summary

Constructors
Constructor and Description

GroupLayout(Container host)
Creates a GroupLayout for the specified Container.

Constructors
Constructor and Description
`GroupLayout(Container host)` Creates a GroupLayout for the specified Container.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`GroupLayout.ParallelGroup`	`createBaselineGroup(boolean resizable, boolean anchorBaselineToTop)` Creates and returns a `ParallelGroup` that aligns it's elements along the baseline.
`GroupLayout.ParallelGroup`	`createParallelGroup()` Creates and returns a `ParallelGroup` with a `LEADING` alignment.
`GroupLayout.ParallelGroup`	`createParallelGroup(int alignment)` Creates and returns an `ParallelGroup`.
`GroupLayout.ParallelGroup`	`createParallelGroup(int alignment, boolean resizable)` Creates and returns an `ParallelGroup`.
`GroupLayout.SequentialGroup`	`createSequentialGroup()` Creates and returns a `SequentialGroup`.
`boolean`	`getAutocreateContainerGaps()` Returns whether or not gaps between the container and the first/last components should automatically be created.
`boolean`	`getAutocreateGaps()` Returns true if gaps between components are automatically be created.
`boolean`	`getHonorsVisibility()` Returns whether component visibility is considered when sizing and positioning components.
`GroupLayout.Group`	`getHorizontalGroup()` Returns the `Group` that is responsible for layout along the horizontal axis.
`LayoutStyle`	`getLayoutStyle()` Returns the LayoutStyle instance to use
`Dimension`	`getPreferredSize(Container parent)` Returns the preferred size for the specified container.
`GroupLayout.Group`	`getVerticalGroup()` Returns the `ParallelGroup` that is responsible for layout along the vertical axis.
`void`	`layoutContainer(Container parent)` Lays out the specified container.
`void`	`linkSize(Component[] components)` Forces the set of components to have the same size.
`void`	`linkSize(Component[] components, int axis)` Forces the set of components to have the same size.
`void`	`removeLayoutComponent(Component component)` Notification that a `Component` has been removed from the parent container.
`void`	`replace(Component existingComponent, Component newComponent)` Removes an existing component replacing it with the specified component.
`void`	`setAutocreateContainerGaps(boolean autocreatePadding)` Sets whether or not gaps between the container and the first/last components should automatically be created.
`void`	`setAutocreateGaps(boolean autocreatePadding)` Sets whether or not a gap between components should automatically be created.
`void`	`setHonorsVisibility(boolean honorsVisibility)` Sets whether component visibility is considered when sizing and positioning components.
`void`	`setHonorsVisibility(Component component, Boolean honorsVisibility)` Sets whether the component's visibility is considered for sizing and positioning.
`void`	`setHorizontalGroup(GroupLayout.Group group)` Sets the `Group` that is responsible for layout along the horizontal axis.
`void`	`setLayoutStyle(LayoutStyle layoutStyle)` Sets the LayoutStyle this GroupLayout is to use.
`void`	`setVerticalGroup(GroupLayout.Group group)` Sets the `Group` that is responsible for layout along the vertical axis.
`String`	`toString()` Returns a textual description of this GroupLayout.

Methods inherited from class com.codename1.ui.layouts.Layout
addLayoutComponent, cloneConstraint, equals, getChildrenInTraversalOrder, getComponentConstraint, hashCode, isConstraintTracking, isOverlapSupported, obscuresPotential, overridesTabIndices, updateTabIndices

Methods inherited from class java.lang.Object
clone, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - NORTH
```
public static final int NORTH
```
    Compass-direction North (up).
    
    See Also:
    
    Constant Field Values
  - EAST
```
public static final int EAST
```
    Compass-direction east (right).
    
    See Also:
    
    Constant Field Values
  - SOUTH
```
public static final int SOUTH
```
    Compass-direction south (down).
    
    See Also:
    
    Constant Field Values
  - WEST
```
public static final int WEST
```
    Compass-direction west (left).
    
    See Also:
    
    Constant Field Values
  - HORIZONTAL
```
public static final int HORIZONTAL
```
    Possible argument when linking sizes of components. Specifies the the two component should share the same size along the horizontal axis.
    
    See Also:
    
    linkSize(Component[], int), Constant Field Values
  - VERTICAL
```
public static final int VERTICAL
```
    Possible argument when linking sizes of components. Specifies the the two component should share the same size along the vertical axis.
    
    See Also:
    
    linkSize(Component[],int), Constant Field Values
  - LEADING
```
public static final int LEADING
```
    Possible alignment type. Indicates the elements should be aligned to the origin. For the horizontal axis with a left to right orientation this means aligned to the left.
    
    See Also:
    
    createParallelGroup(int), Constant Field Values
  - TRAILING
```
public static final int TRAILING
```
    Possible alignment type. Indicates the elements should be aligned to the end. For the horizontal axis with a left to right orientation this means aligned to the right.
    
    See Also:
    
    createParallelGroup(int), Constant Field Values
  - CENTER
```
public static final int CENTER
```
    Possible alignment type. Indicates the elements should centered in the spaced provided.
    
    See Also:
    
    createParallelGroup(int), Constant Field Values
  - BASELINE
```
public static final int BASELINE
```
    Possible alignment type. Indicates the elements should aligned along their baseline.
    
    See Also:
    
    createParallelGroup(int), Constant Field Values
  - DEFAULT_SIZE
```
public static final int DEFAULT_SIZE
```
    Possible value for the add methods that takes a Component. Indicates the size from the component should be used.
    
    See Also:
    
    Constant Field Values
  - PREFERRED_SIZE
```
public static final int PREFERRED_SIZE
```
    Possible value for the add methods that takes a Component. Indicates the preferred size should be used.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - GroupLayout
```
public GroupLayout(Container host)
```
    Creates a GroupLayout for the specified Container.
    
    Parameters:
    
    host - the Container to layout
    
    Throws:
    
    IllegalArgumentException - if host is null
- Method Detail
  - setHonorsVisibility
```
public void setHonorsVisibility(boolean honorsVisibility)
```
    Sets whether component visibility is considered when sizing and positioning components. A value of true indicates that non-visible components should not be treated as part of the layout. A value of false indicates that components should be positioned and sized regardless of visibility.
    A value of false is useful when the visibility of components is dynamically adjusted and you don't want surrounding components and the sizing to change.
    The specified value is used for components that do not have an explicit visibility specified.
    The default is true.
    
    Parameters:
    
    honorsVisibility - whether component visibility is considered when sizing and positioning components
    
    See Also:
    
    setHonorsVisibility(Component,Boolean)
  - getHonorsVisibility
```
public boolean getHonorsVisibility()
```
    Returns whether component visibility is considered when sizing and positioning components.
    
    Returns:
    
    whether component visibility is considered when sizing and positioning components
  - setHonorsVisibility
```
public void setHonorsVisibility(Component component,
                                Boolean honorsVisibility)
```
    Sets whether the component's visibility is considered for sizing and positioning. A value of Boolean.TRUE indicates that if component is not visible it should not be treated as part of the layout. A value of false indicates that component is positioned and sized regardless of it's visibility. A value of null indicates the value specified by the single argument method setHonorsVisibility should be used.
    If component is not a child of the Container this GroupLayout is managing, it will be added to the Container.
    
    Parameters:
    
    component - the component
    
    honorsVisibility - whether component's visibility should be considered for sizing and positioning
    
    Throws:
    
    IllegalArgumentException - if component is null
    
    See Also:
    
    setHonorsVisibility(boolean)
  - toString
```
public String toString()
```
    Returns a textual description of this GroupLayout. The return value is intended for debugging purposes only.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    textual description of this GroupLayout
  - setAutocreateGaps
```
public void setAutocreateGaps(boolean autocreatePadding)
```
    Sets whether or not a gap between components should automatically be created. For example, if this is true and you add two components to a SequentialGroup a gap between the two will automatically be created. The default is false.
    
    Parameters:
    
    autocreatePadding - whether or not to automatically created a gap between components and the container
  - getAutocreateGaps
```
public boolean getAutocreateGaps()
```
    Returns true if gaps between components are automatically be created.
    
    Returns:
    
    true if gaps between components should automatically be created
  - setAutocreateContainerGaps
```
public void setAutocreateContainerGaps(boolean autocreatePadding)
```
    Sets whether or not gaps between the container and the first/last components should automatically be created. The default is false.
    
    Parameters:
    
    autocreatePadding - whether or not to automatically create gaps between the container and first/last components.
  - getAutocreateContainerGaps
```
public boolean getAutocreateContainerGaps()
```
    Returns whether or not gaps between the container and the first/last components should automatically be created. The default is false.
    
    Returns:
    
    whether or not the gaps between the container and the first/last components should automatically be created
  - setHorizontalGroup
```
public void setHorizontalGroup(GroupLayout.Group group)
```
    Sets the Group that is responsible for layout along the horizontal axis.
    
    Parameters:
    
    group - Group responsible for layout along the horizontal axis
    
    Throws:
    
    IllegalArgumentException - if group is null
  - getHorizontalGroup
```
public GroupLayout.Group getHorizontalGroup()
```
    Returns the Group that is responsible for layout along the horizontal axis.
    
    Returns:
    
    ParallelGroup responsible for layout along the horizontal axis.
  - setVerticalGroup
```
public void setVerticalGroup(GroupLayout.Group group)
```
    Sets the Group that is responsible for layout along the vertical axis.
    
    Parameters:
    
    group - Group responsible for layout along the vertical axis.
    
    Throws:
    
    IllegalArgumentException - if group is null.
  - getVerticalGroup
```
public GroupLayout.Group getVerticalGroup()
```
    Returns the ParallelGroup that is responsible for layout along the vertical axis.
    
    Returns:
    
    ParallelGroup responsible for layout along the vertical axis.
  - createSequentialGroup
```
public GroupLayout.SequentialGroup createSequentialGroup()
```
    Creates and returns a SequentialGroup.
    
    Returns:
    
    a new SequentialGroup
  - createParallelGroup
```
public GroupLayout.ParallelGroup createParallelGroup()
```
    Creates and returns a ParallelGroup with a LEADING alignment. This is a cover method for the more general createParallelGroup(int) method.
    
    Returns:
    
    a new ParallelGroup
    
    See Also:
    
    createParallelGroup(int)
  - createParallelGroup
```
public GroupLayout.ParallelGroup createParallelGroup(int alignment)
```
    Creates and returns an ParallelGroup. The alignment specifies how children elements should be positioned when the the parallel group is given more space than necessary. For example, if a ParallelGroup with an alignment of TRAILING is given 100 pixels and a child only needs 50 pixels, the child will be positioned at the position 50.
    
    Parameters:
    
    alignment - alignment for the elements of the Group, one of LEADING, TRAILING, CENTER or BASELINE.
    
    Returns:
    
    a new ParallelGroup
    
    Throws:
    
    IllegalArgumentException - if alignment is not one of LEADING, TRAILING, CENTER or BASELINE
  - createParallelGroup
```
public GroupLayout.ParallelGroup createParallelGroup(int alignment,
                                                     boolean resizable)
```
    Creates and returns an ParallelGroup. The alignment specifies how children elements should be positioned when the the parallel group is given more space than necessary. For example, if a ParallelGroup with an alignment of TRAILING is given 100 pixels and a child only needs 50 pixels, the child will be positioned at the position 50.
    
    Parameters:
    
    alignment - alignment for the elements of the Group, one of LEADING, TRAILING, CENTER or BASELINE.
    
    resizable - whether or not the group is resizable. If the group is not resizable the min/max size will be the same as the preferred.
    
    Returns:
    
    a new ParallelGroup
    
    Throws:
    
    IllegalArgumentException - if alignment is not one of LEADING, TRAILING, CENTER or BASELINE
  - createBaselineGroup
```
public GroupLayout.ParallelGroup createBaselineGroup(boolean resizable,
                                                     boolean anchorBaselineToTop)
```
    Creates and returns a ParallelGroup that aligns it's elements along the baseline.
    
    Parameters:
    
    resizable - whether the group is resizable
    
    anchorBaselineToTop - whether the baseline is anchored to the top or bottom of the group
    
    Returns:
    
    parallel group
    
    See Also:
    
    createBaselineGroup(boolean, boolean), GroupLayout.ParallelGroup
  - linkSize
```
public void linkSize(Component[] components)
```
    Forces the set of components to have the same size. This can be used multiple times to force any number of components to share the same size.
    Linked Components are not be resizable.
    
    Parameters:
    
    components - Components to force to have same size.
    
    Throws:
    
    IllegalArgumentException - if components is null, or contains null.
  - linkSize
```
public void linkSize(Component[] components,
                     int axis)
```
    Forces the set of components to have the same size. This can be used multiple times to force any number of components to share the same size.
    Linked Components are not be resizable.
    
    Parameters:
    
    components - Components to force to have same size.
    
    axis - Axis to bind size, one of HORIZONTAL, VERTICAL or HORIZONTAL | VERTICAL
    
    Throws:
    
    IllegalArgumentException - if components is null, or contains null.
    
    IllegalArgumentException - if axis does not contain HORIZONTAL or VERTICAL
  - replace
```
public void replace(Component existingComponent,
                    Component newComponent)
```
    Removes an existing component replacing it with the specified component.
    
    Parameters:
    
    existingComponent - the Component that should be removed and replaced with newComponent
    
    newComponent - the Component to put in existingComponents place
    
    Throws:
    
    IllegalArgumentException - is either of the Components are null or if existingComponent is not being managed by this layout manager
  - setLayoutStyle
```
public void setLayoutStyle(LayoutStyle layoutStyle)
```
    Sets the LayoutStyle this GroupLayout is to use. A value of null can be used to indicate the shared instance of LayoutStyle should be used.
    
    Parameters:
    
    layoutStyle - the LayoutStyle to use
  - getLayoutStyle
```
public LayoutStyle getLayoutStyle()
```
    Returns the LayoutStyle instance to use
    
    Returns:
    
    the LayoutStyle instance to use
  - removeLayoutComponent
```
public void removeLayoutComponent(Component component)
```
    Notification that a Component has been removed from the parent container. You should not invoke this method directly, instead invoke removeComponent on the parent Container.
    
    Overrides:
    
    removeLayoutComponent in class Layout
    
    Parameters:
    
    component - the component to be removed
    
    See Also:
    
    Container.removeComponent(com.codename1.ui.Component)
  - getPreferredSize
```
public Dimension getPreferredSize(Container parent)
```
    Returns the preferred size for the specified container.
    
    Specified by:
    
    getPreferredSize in class Layout
    
    Parameters:
    
    parent - the container to return size for
    
    Returns:
    
    the container preferred size
    
    Throws:
    
    IllegalArgumentException - if parent is not the same Container that this was created with
    
    IllegalStateException - if any of the components added to this layout are not in both a horizontal and vertical group
    
    See Also:
    
    Component.getPreferredSize()
  - layoutContainer
```
public void layoutContainer(Container parent)
```
    Lays out the specified container.
    
    Specified by:
    
    layoutContainer in class Layout
    
    Parameters:
    
    parent - the container to be laid out
    
    Throws:
    
    IllegalStateException - if any of the components added to this layout are not in both a horizontal and vertical group

Class GroupLayout

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.codename1.ui.layouts.Layout

Methods inherited from class java.lang.Object

Field Detail

NORTH

EAST

SOUTH

WEST

HORIZONTAL

VERTICAL

LEADING

TRAILING

CENTER

BASELINE

DEFAULT_SIZE

PREFERRED_SIZE

Constructor Detail

GroupLayout

Method Detail

setHonorsVisibility

getHonorsVisibility

setHonorsVisibility

toString

setAutocreateGaps

getAutocreateGaps

setAutocreateContainerGaps

getAutocreateContainerGaps

setHorizontalGroup

getHorizontalGroup

setVerticalGroup

getVerticalGroup

createSequentialGroup

createParallelGroup

createParallelGroup

createParallelGroup

createBaselineGroup

linkSize

linkSize

replace

setLayoutStyle

getLayoutStyle

removeLayoutComponent

getPreferredSize

layoutContainer