AbsoluteLayout

Since: BlackBerry 10.0.0

#include <bb/cascades/AbsoluteLayout>

A Layout that allows you to set X and Y coordinates for controls.

The following figure shows an absolute layout with three images positioned to be slightly overlapping (and rotated).

No caption available

When controls are added to the container, they are positioned at (0,0) unless X and Y coordinates are specified in the child control's layoutProperties. When applying layoutProperties to a control, you must ensure that you use an AbsoluteLayoutProperties object, otherwise the layout properties will be ignored.

Though the absolute layout allows for the precise positioning of controls, for most UIs it's recommended that you use one of the other layouts instead (e.g. StackLayout or DockLayout). When using AbsoluteLayout, resizing the UI for different displays and handling orientation changes becomes difficult. In cases where the dimensions are relatively static, such as with a custom control, using an absolute layout might be the preferred option.

The following examples demonstrates how to position a button using an AbsoluteLayout. The X and Y coordinates are set to 100, 100.

No caption available

QML:

Container {
    layout: AbsoluteLayout {}
     
    Button {
        text: "Button"
        layoutProperties: AbsoluteLayoutProperties {
            positionX: 100
            positionY: 100    
        }                
    }    
}

C++:

Container* pContainer = new Container();
AbsoluteLayout *pAbsoluteLayout = new AbsoluteLayout();
pContainer->setLayout(pAbsoluteLayout);

AbsoluteLayoutProperties* pProperties = AbsoluteLayoutProperties::create();
pProperties->setPositionX(100.0);
pProperties->setPositionY(100.0);

Button* pButton = Button::create().text("Button");
pButton->setLayoutProperties(pProperties);
pContainer->add( pButton );


Overview

QML properties

Only has inherited QML properties

attachedObjects: QDeclarativeListProperty< QObject > [read-only]Inherited
objectName: QStringInherited
parent: QObject [read-only]Inherited
ui: bb::cascades::UIConfig [read-only]Inherited

QML signals

Only has inherited QML signals

onCreationCompletedInherited: {}
onObjectNameChangedInherited: {}

Properties Index

Only has inherited properties

QDeclarativeListProperty< QObject >attachedObjects [read-only]Inherited
QStringobjectNameInherited
QObjectparent [read-only]Inherited
bb::cascades::UIConfigui [read-only]Inherited

Public Functions Index

AbsoluteLayout ()
virtual ~AbsoluteLayout ()
virtual boolevent (QEvent *event)Inherited
voidsetObjectName (const QString &name)Inherited
virtual Q_INVOKABLE QStringtoDebugString () const Inherited
Q_INVOKABLE bb::cascades::UIConfig *ui () const Inherited

Static Public Functions Index

Buildercreate ()

Protected Functions Index

Only has inherited protected functions

BaseObject (QObject *parent=0)Inherited
virtual voidconnectNotify (const char *signal)Inherited
virtual voiddisconnectNotify (const char *signal)Inherited

Signals Index

Only has inherited signals

voidcreationCompleted ()Inherited
voidobjectNameChanged (const QString &objectName)Inherited

Properties

(Only has inherited properties)

QDeclarativeListProperty< QObject > attachedObjectsInherited[read-only]

A hierarchical list of the UIObject's attached objects.

Since:

BlackBerry 10.0.0

QString objectNameInherited

This property is overridden from QObject.

See also:

QObject::objectName().

Since:

BlackBerry 10.0.0

QObject parentInherited[read-only]

A read-only property that represents this object's parent.

The parent of an object is specified using QObject::setParent(QObject*). The purpose of the property is to expose the object's parent to QML.

This property is read-only to prevent modifications from QML, where typically the parent is declaratively set. In C++ code, the parent can be explicitly set using QObject::setParent(QObject*), or implicitly set by adding it to a visual container.

The default value of this property is 0.

Since:

BlackBerry 10.0.0

bb::cascades::UIConfig uiInherited[read-only]

An object that gives access to unit conversion routines.

QML use:
        // Size using design units
        Container {
            preferredWidth: ui.du(12)
            preferredHeight: ui.du(5)
        }

        // Size using design units, snap to whole pixels
        Container {
            preferredWidth: ui.sdu(13.5)
            preferredHeight: ui.sdu(7.5)
        }

        // Size using absolute pixel values
        Container {
            preferredWidth: ui.px(150)
            preferredHeight: ui.px(50)
        }
C++ use:
Container *container1 = Container::create().background(Color::Red);
UIConfig *ui = container1->ui();
container1->setPreferredWidth(ui->du(12));
container1->setPreferredHeight(ui->du(5));

Container *container2 = Container::create().background(Color::Green);
container2->setPreferredWidth(ui->sdu(13.5));
container2->setPreferredHeight(ui->sdu(7.5));

Container *container3 = Container::create().background(Color::Blue);
container3->setPreferredWidth(ui->px(150));
container3->setPreferredHeight(ui->sdu(50));
Since:

Blackberry 10.3.0

Public Functions

AbsoluteLayout ()

Constructs an AbsoluteLayout object.

Since:

BlackBerry 10.0.0

virtual~AbsoluteLayout ()

Destructor.

virtual bool event (Inherited

Overloaded to implement the event mechanism in Cascades.

Warning!

If this function is overridden, it must be called by the derived class for events to work properly in Cascades.

Parameters
event

The received event.

Return:

True if the received event was recognized and processed, false otherwise.

Since:

BlackBerry 10.0.0

void setObjectName (Inherited

Sets the objectName property.

Parameters
name

The new name for the object.

Since:

BlackBerry 10.0.0

virtual Q_INVOKABLE QString toDebugString ()Inherited

Returns a debug string representing this object.

Return:

A debug string for the object.

Since:

BlackBerry 10.0.0

Q_INVOKABLE bb::cascades::UIConfig * ui ()Inherited

Returns the UIConfig for this ui object.

The UIConfig can be used to perform unit conversions from design units (du) and snapped design units (sdu) to pixels.

Ownership remains with Cascades.

C++ use:
Container *container1 = Container::create().background(Color::Red);
UIConfig *ui = container1->ui();
container1->setPreferredWidth(ui->du(12));
container1->setPreferredHeight(ui->du(5));

Container *container2 = Container::create().background(Color::Green);
container2->setPreferredWidth(ui->sdu(13.5));
container2->setPreferredHeight(ui->sdu(7.5));

Container *container3 = Container::create().background(Color::Blue);
container3->setPreferredWidth(ui->px(150));
container3->setPreferredHeight(ui->sdu(50));
Return:

The UIConfig for this ui object.

Since:

BlackBerry 10.3.0

Static Public Functions

Builder create ()

Creates and returns a builder for constructing an AbsoluteLayout.

Using the builder to create an AbsoluteLayout object:
AbsoluteLayout* pAbsoluteLayout = AbsoluteLayout::create()
Return:

A builder used for constructing an AbsoluteLayout object.

Since:

BlackBerry 10.0.0

Protected Functions

(Only has inherited protected functions)

BaseObject (Inherited

Constructs an instance of BaseObject's subclass.

Parameters
parent

An optional parent, defaults to 0.

Since:

BlackBerry 10.0.0

virtual void connectNotify (
  • const char *signal)
Inherited

Overloaded to implement the event mechanism in Cascades.

If this function is overridden, it must be called by the derived class for events to work properly in Cascades.

Parameters
signal

The connected signal.

Since:

BlackBerry 10.0.0

virtual void disconnectNotify (
  • const char *signal)
Inherited

Overloaded to implement the event mechanism in Cascades.

If this function is overridden, it must be called by the derived class for events to work properly in Cascades.

Parameters
signal

The disconnected signal.

Since:

BlackBerry 10.0.0

Signals

(Only has inherited signals)

void creationCompleted ()Inherited

Emitted when this object is instantiated as a result of loading a QML document and creating the root node (only after the root component that caused this instantiation has completed construction), or when the object is being constructed from its builder class.

This signal indicates that the construction and initialization of the object has been completed, the properties are initialized, and any QML binding values have been assigned to the object.

This signal is not emitted when the object is constructed from C++ using the constructor. If the object is constructed using its builder class, the signal is emitted when the the builder class returns the fully constructed object.

This signal can be used when there is an activity that needs to be performed, such as a property state integrity verification after the object is instantiated from a QML document or a builder, but before control is returned to the application.

See also:

QmlDocument

Since:

BlackBerry 10.0.0

void objectNameChanged (Inherited

This signal is emitted when the objectName property is changed.

Since:

BlackBerry 10.0.0

Last modified: 2014-06-24



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