public class FlowLayout

Object
Layout
FlowLayout

FlowLayout is the default layout manager for Codename One Containers and Forms. It places components in a row one after another based on their preferred size. When it reaches the edge of the container it will break a line and start a new row.

Form hi = new Form("Flow Layout", new FlowLayout());
hi.add(new Label("First")).
    add(new Label("Second")).
    add(new Label("Third")).
    add(new Label("Fourth")).
    add(new Label("Fifth"));
hi.show();

Since flow layout isn’t a constraint based layout it has a bunch of very useful enclose methods that can significantly reduce the code required to create the same UI e.g.:

Container flowLayout = FlowLayout.encloseIn(new Label("First"),
        new Label("Second"),
        new Label("Third"),
        new Label("Fourth"),
        new Label("Fifth"));

This class works nicely for simple elements, however since Codename One doesn’t reflow recursively (for performance) it can’t accurately handle complex layouts. As a result when an element of varying size is placed in a flow layout this confuses the line breaking logic and fails in odd ways. That is why this layout should only be used for relatively simple use cases.

Flow layout supports aligning the component horizontally and vertically, it defaults to the top left alignment for LTR languages. E.g. the following alignments are supported thru the usage of setAlign & setValign.

E.g. you can align to the center

You can align to the right

You can align to the center and the middle horizontally

There are quite a few additional combinations that are possible with these API’s.

Constructors

`public FlowLayout()`	Creates a new instance of FlowLayout with left alignment
`public FlowLayout(int orientation)`	Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER
`public FlowLayout(int orientation, int valign)`	Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER and the vertical orientation
`public FlowLayout(int orientation, int valign, boolean vAlignByRow)`	Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER and the vertical orientation

Methods

`public static` `Container encloseIn(Component... cmps)`	Shorthand for `com.codename1.ui.Component...)` with a `FlowLayout instance` see:
`public static` `Container encloseCenter(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER), cmps);
`public static` `Container encloseRight(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT), cmps);
`public static` `Container encloseMiddle(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);
`public static` `Container encloseMiddleByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER, true), cmps);
`public static` `Container encloseCenterMiddle(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER), cmps);
`public static` `Container encloseCenterMiddleByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER, true), cmps);
`public static` `Container encloseRightMiddle(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER), cmps);
`public static` `Container encloseRightMiddleByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER, true), cmps);
`public static` `Container encloseLeftMiddle(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);
`public static` `Container encloseLeftMiddleByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER, true), cmps);
`public static` `Container encloseBottom(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM), cmps);
`public static` `Container encloseCenterBottom(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM), cmps);
`public static` `Container encloseRightBottom(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM), cmps);
`public static` `Container encloseBottomByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM, true), cmps);
`public static` `Container encloseCenterBottomByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM, true), cmps);
`public static` `Container encloseRightBottomByRow(Component... cmps)`	Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM, true), cmps);
`public void layoutContainer(Container parent)`	Layout the given parent container children
`protected void fillRow(Container target, int width, int start, int end)`	This method tries to fill up the available space in a row.
`public` `Dimension getPreferredSize(Container parent)`	Returns the container preferred size
`public` `String toString()`	Returns a string representation of the object.
`public boolean isFillRows()`	Indicates whether the layout manager should try to fill up the available space in the row
`public void setFillRows(boolean fillRows)`	Indicates whether the layout manager should try to fill up the available space in the row
`public int getValign()`	Indicates vertical alignment within the flow layout
`public void setValign(int valign)`	Indicates vertical alignment within the flow layout
`public boolean isValignByRow()`	Returns whether vertical alignment is done internally or externally
`public void setValignByRow(boolean internal)`	When set to true vertical alignment will be performed by row (components within the container will be aligned vertically to each other in the same row) When set to false (which is default) vertical alignment relates to the alignment of this…
`public int getAlign()`	Alignment of the flow layout, defaults to LEFT
`public void setAlign(int orientation)`	Alignment of the flow layout, defaults to LEFT
`public boolean equals(Object o)`	Indicates whether some other object is “equal to” this one.
`public int hashCode()`	Returns a hash code value for the object.

Inherited methods

From Layout

addLayoutComponent, removeLayoutComponent, getComponentConstraint, cloneConstraint, isOverlapSupported, isConstraintTracking, obscuresPotential, overridesTabIndices, updateTabIndices, getChildrenInTraversalOrder

From Object

getClass, notify, notifyAll, wait, wait, wait, clone

Constructor details

FlowLayout

public FlowLayout()

Creates a new instance of FlowLayout with left alignment

FlowLayout

public FlowLayout(int orientation)

Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER

Parameters

orientation int: the orientation value

FlowLayout

public FlowLayout(int orientation, int valign)

Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER and the vertical orientation

Parameters

orientation int: the orientation value
valign int: the vertical orientation one of Component.TOP/BOTTOM/CENTER

FlowLayout

public FlowLayout(int orientation, int valign, boolean vAlignByRow)

Creates a new instance of FlowLayout with the given orientation one of LEFT, RIGHT or CENTER and the vertical orientation

Parameters

orientation int: the orientation value
valign int: the vertical orientation one of Component.TOP/BOTTOM/CENTER
vAlignByRow boolean: whether vertical alignment should be computed by row elements

Method details

encloseIn

public static Container encloseIn(Component... cmps)

Shorthand for com.codename1.ui.Component...) with a FlowLayout instance see:

Container flowLayout = FlowLayout.encloseIn(new Label("First"),
        new Label("Second"),
        new Label("Third"),
        new Label("Fourth"),
        new Label("Fifth"));

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseCenter

public static Container encloseCenter(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseRight

public static Container encloseRight(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseMiddle

public static Container encloseMiddle(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseMiddleByRow

public static Container encloseMiddleByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseCenterMiddle

public static Container encloseCenterMiddle(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseCenterMiddleByRow

public static Container encloseCenterMiddleByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseRightMiddle

public static Container encloseRightMiddle(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseRightMiddleByRow

public static Container encloseRightMiddleByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseLeftMiddle

public static Container encloseLeftMiddle(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseLeftMiddleByRow

public static Container encloseLeftMiddleByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseBottom

public static Container encloseBottom(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseCenterBottom

public static Container encloseCenterBottom(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseRightBottom

public static Container encloseRightBottom(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseBottomByRow

public static Container encloseBottomByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseCenterBottomByRow

public static Container encloseCenterBottomByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

encloseRightBottomByRow

public static Container encloseRightBottomByRow(Component... cmps)

Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM, true), cmps);

Parameters

cmps Component...: the components to enclose in a new container

Returns

the new container

layoutContainer

public void layoutContainer(Container parent)

Layout the given parent container children

Parameters

parent Container: the given parent container

fillRow

protected void fillRow(Container target, int width, int start, int end)

This method tries to fill up the available space in a row. This method is called if isFillRows() returns true.

Parameters

target Container: the parent container
width int: the width of the row to fill
start int: the index of the first component in this row
end int: the index of the last component in this row

getPreferredSize

public Dimension getPreferredSize(Container parent)

Returns the container preferred size

Parameters

parent Container: the parent container

Returns

the container preferred size

toString

public String toString()

Returns a string representation of the object. In general, the toString method returns a string that “textually represents” this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@’, and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of: getClass().getName() + ‘@’ + Integer.toHexString(hashCode())

isFillRows

public boolean isFillRows()

Indicates whether the layout manager should try to fill up the available space in the row

Returns

the fillRows

setFillRows

public void setFillRows(boolean fillRows)

Indicates whether the layout manager should try to fill up the available space in the row

Parameters

fillRows boolean: the fillRows to set

getValign

public int getValign()

Indicates vertical alignment within the flow layout

Returns

Component.TOP/BOTTOM/CENTER

setValign

public void setValign(int valign)

Indicates vertical alignment within the flow layout

Parameters

valign int: one of Component.TOP/BOTTOM/CENTER

isValignByRow

public boolean isValignByRow()

Returns whether vertical alignment is done internally or externally

Returns

whether vertical alignment is done internally or externally

setValignByRow

public void setValignByRow(boolean internal)

When set to true vertical alignment will be performed by row (components within the container will be aligned vertically to each other in the same row) When set to false (which is default) vertical alignment relates to the alignment of this container in regards to external components

Parameters

internal boolean: true for internal, false otherwise

getAlign

public int getAlign()

Alignment of the flow layout, defaults to LEFT

Returns

the orientation

setAlign

public void setAlign(int orientation)

Alignment of the flow layout, defaults to LEFT

Parameters

orientation int: the orientation to set

equals

public boolean equals(Object o)

Indicates whether some other object is “equal to” this one. The equals method implements an equivalence relation: It is reflexive: for any reference value x, x.equals(x) should return true. It is symmetric: for any reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true. It is transitive: for any reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true. It is consistent: for any reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the object is modified. For any non-null reference value x, x.equals(null) should return false. The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any reference values x and y, this method returns true if and only if x and y refer to the same object (x==y has the value true).

hashCode

public int hashCode()

Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable. The general contract of hashCode is: Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables. As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)