StackLayout

Since: BlackBerry 10.0.0

#include <bb/cascades/StackLayout>

A layout that is used to position a container's children in a stack.

The stack can be either vertical or horizontal, depending on the orientation. The default orientation is LayoutOrientation::TopToBottom. The StackLayoutProperties class contains additional layout properties that you can set on the individual children within the Container.

By using the Control::horizontalAlignment and Control::verticalAlignment properties you can specify where controls are positioned horizontally (left, center, or right) and vertically (top, center, bottom) within the containers area in the StackLayout. Controls can also be expanded/contracted to fill the container in a specified direction.

In cases where children must not extend outside a container's borders, the padding property can be used to create some separation between the boundary of the container and its child controls. Each boundary of a container (left, right, top and bottom) can have a different value set on it.

For example, setting the left padding to 10 would mean that the left-most 10 pixels of the layout container will not be available to the child controls.

In the following examples, a StackLayout is used to position some buttons in a vertical stack, centered on the screen.

QML:

 Container {
     layout: StackLayout {}

     Button {
         text: "Button1"
         layoutProperties: StackLayoutProperties {}
         horizontalAlignment: HorizontalAlignment.Center
     }
     Button {
         text: "Button2"
         layoutProperties: StackLayoutProperties {}
         horizontalAlignment: HorizontalAlignment.Center
     }
     Button {
         text: "Button3"
         layoutProperties: StackLayoutProperties {}
         horizontalAlignment: HorizontalAlignment.Center
     }               
 }

C++:

 Container* pContainer = new Container();
 StackLayout *pStackLayout = new StackLayout();
 pStackLayout->setOrientation( LayoutOrientation::TopToBottom );
 pContainer->setLayout(pStackLayout);
 
 Button* pButton1 = Button::create().text("Button1");
 Button* pButton2 = Button::create().text("Button2");
 Button* pButton3 = Button::create().text("Button3");

 pButton1->setLayoutProperties( StackLayoutProperties::create()
         .horizontal( HorizontalAlignment::Center ) );
 pButton2->setLayoutProperties( StackLayoutProperties::create()
         .horizontal( HorizontalAlignment::Center ) );
 pButton3->setLayoutProperties( StackLayoutProperties::create()
         .horizontal( HorizontalAlignment::Center ) );

 pContainer->add( pButton1 );
 pContainer->add( pButton2 );
 pContainer->add( pButton3 );

Overview

Inheritance

bb::cascades::BaseObject
	bb::cascades::UIObject
		bb::cascades::Layout
			bb::cascades::StackLayout

QML properties

orientation	: bb::cascades::LayoutOrientation::Type
attachedObjects	: QDeclarativeListProperty< QObject > [read-only]
objectName	: QString
parent	: QObject [read-only]
ui	: bb::cascades::UIConfig [read-only]

QML signals

onOrientationChanged	: {}
onCreationCompleted	: {}
onObjectNameChanged	: {}

Properties Index

bb::cascades::LayoutOrientation::Type	orientation
QDeclarativeListProperty< QObject >	attachedObjects [read-only]
QString	objectName
QObject	parent [read-only]
bb::cascades::UIConfig	ui [read-only]

Public Functions Index

	StackLayout ()
virtual	~StackLayout ()
bb::cascades::LayoutOrientation::Type	orientation () const
Q_SLOT void	resetOrientation ()
Q_SLOT void	setOrientation (bb::cascades::LayoutOrientation::Type orientation)
virtual bool	event (QEvent *event)
void	setObjectName (const QString &name)
virtual Q_INVOKABLE QString	toDebugString () const
Q_INVOKABLE bb::cascades::UIConfig *	ui () const

Static Public Functions Index

Builder

create ()

Protected Functions Index

Only has inherited protected functions

	BaseObject (QObject *parent=0)
virtual void	connectNotify (const char *signal)
virtual void	disconnectNotify (const char *signal)

Signals Index

void	orientationChanged (bb::cascades::LayoutOrientation::Type newOrientation)
void	creationCompleted ()
void	objectNameChanged (const QString &objectName)

Properties

bb::cascades::LayoutOrientation::Type orientation

The orientation for the stack layout.

See also:

LayoutOrientation

Since:

BlackBerry 10.0.0

QDeclarativeListProperty< QObject > attachedObjects[read-only]

A hierarchical list of the UIObject's attached objects.

Since:

BlackBerry 10.0.0

QString objectName

This property is overridden from QObject.

See also:

QObject::objectName().

Since:

BlackBerry 10.0.0

QObject parent[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 ui[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

StackLayout ()

Constructs a StackLayout object.

When you set a layout on a container using Container::setLayout the container assumes ownership of this instance.

Since:

BlackBerry 10.0.0

virtual~StackLayout ()

Destructor.

bb::cascades::LayoutOrientation::Type orientation ()

Returns the orientation for the stack layout.

Return:

The orientation.

Since:

BlackBerry 10.0.0

Q_SLOT void resetOrientation ()

Resets the orientation to its default.

The default orientation is LayoutOrientation::TopToBottom.

After the orientation is reset, the orientationChanged() signal is emitted.

Since:

BlackBerry 10.0.0

Q_SLOT void setOrientation (
bb::cascades::LayoutOrientation::Typeorientation)

Sets the orientation for the stack layout.

After the orientation is set, the orientationChanged() signal is emitted.

Parameters
orientation	The new orientation.

Since:

BlackBerry 10.0.0

virtual bool event (
QEvent *event)

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 (
const QString &name)

Sets the objectName property.

Parameters
name	The new name for the object.

Since:

BlackBerry 10.0.0

virtual Q_INVOKABLE QString toDebugString ()

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 ()

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 a stack layout.

Using the builder to create a stack layout:

 StackLayout* stackLayout = StackLayout::create()
         .orientation(LayoutOrientation::LeftToRight);

Return:

A builder used for constructing a stack layout.

Since:

BlackBerry 10.0.0

Protected Functions

(Only has inherited protected functions)

BaseObject (
QObject *parent)

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)

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)

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

void orientationChanged (
bb::cascades::LayoutOrientation::TypenewOrientation)

Emitted when the orientation property changes.

Note:

Due to a work around for a Qt Core issue with accessing enums from QML the argument of this signal doesn't follow naming convention for signals in which the signal arguments are typically named to match the associated property's name. Use the object's property to access current property value instead of the signal argument to avoid runtime errors (i.e. use orientation instead of newOrientation).

Parameters
newOrientation	The new orientation.

Since:

BlackBerry 10.0.0

void creationCompleted ()

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 (
const QString &objectName)

This signal is emitted when the objectName property is changed.

See also:

QObject, BaseObject::objectName.

Since:

BlackBerry 10.0.0

StackLayout

Overview

Inheritance

QML properties

QML signals

Properties Index

Public Functions Index

Static Public Functions Index

Protected Functions Index

Signals Index

Properties

bb::cascades::LayoutOrientation::Type orientation

QDeclarativeListProperty< QObject > attachedObjects[read-only]

QString objectName

QObject parent[read-only]

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

Public Functions

StackLayout ()

virtual~StackLayout ()

bb::cascades::LayoutOrientation::Type orientation ()

Q_SLOT void resetOrientation ()

Q_SLOT void setOrientation (bb::cascades::LayoutOrientation::Typeorientation)

virtual bool event (QEvent *event)

void setObjectName (const QString &name)

virtual Q_INVOKABLE QString toDebugString ()

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

Static Public Functions

Builder create ()

Protected Functions

BaseObject (QObject *parent)

virtual void connectNotify (const char *signal)

virtual void disconnectNotify (const char *signal)

Signals

void orientationChanged (bb::cascades::LayoutOrientation::TypenewOrientation)

void creationCompleted ()

void objectNameChanged (const QString &objectName)

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Q_SLOT void setOrientation (
bb::cascades::LayoutOrientation::Typeorientation)

virtual bool event (
QEvent *event)

void setObjectName (
const QString &name)

BaseObject (
QObject *parent)

virtual void connectNotify (
const char *signal)

virtual void disconnectNotify (
const char *signal)

void orientationChanged (
bb::cascades::LayoutOrientation::TypenewOrientation)

void objectNameChanged (
const QString &objectName)