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/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\title Qt Quick Demo - Calqlatr
\ingroup qtquickdemos
\example demos/calqlatr
\brief A QML app designed for portrait devices that uses custom components,
animated with AnimationController, and JavaScript for the application logic.
\image qtquick-demo-calqlatr.png
\e{Calqlatr} demonstrates various QML and \l{Qt Quick} features, such as
displaying custom components and using animation to move the components
around in the application view. The application logic is implemented in
JavaScript and the appearance is implemented in QML.
\include examples-run.qdocinc
\section1 Displaying Custom Components
In the Calqlatr application, we use the following custom types that are
each defined in a separate .qml file:
\list
\li Button.qml
\li Display.qml
\li NumberPad.qml
\li StyleLabel.qml
\endlist
To use the custom types, we add an import statement to the main QML file,
calqlatr.qml that imports the folder called \c content where the types are
located:
\code
import "content"
\endcode
We can then display custom components by adding the component types to
any QML file. For example, we use the NumberPad type in calqlatr.qml to
create the number pad of the calculator. We place the type inside an
\l{Item} QML type, which is the base type for all visual items in Qt Quick:
\quotefromfile demos/calqlatr/calqlatr.qml
\skipto Item
\printuntil }
\printuntil }
Further, we use the Button type in the NumberPad type to create the
calculator buttons. Button.qml specifies the basic properties for a
button that we can modify for each button instance in NumberPad.qml. For the
digit and separator buttons, we additionally specify the text property using
the property alias \c text that we define in Button.qml.
For the operator buttons, we also specify another color (green) using the
property alias \c color and set the operator property to \c true. We use
the operator property in functions that perform the calculations.
We place the buttons inside a \l{Grid} QML type to position them in a grid:
\quotefromfile demos/calqlatr/content/NumberPad.qml
\skipto Grid
\printuntil /^\}/
\section1 Animating Components
We use the Display type to display calculations. In Display.qml, we use
images to make the display component look like a slip of paper that contains
a grip. Users can drag the grip to move the display from left to right.
When users release the grip, the AnimationController QML type that we define
in the calqlatr.qml file finishes running the controlled animation in either
a forwards or a backwards direction. To run the animation, we call either
completeToEnd() or completeToBeginning(), depending on the direction. We do
this in the MouseArea's \c onReleased signal handler, where \c controller
is the id of our AnimationController:
\quotefromfile demos/calqlatr/calqlatr.qml
\skipto onPressed
\printuntil }
Unlike other QML animation types, AnimationController is not driven by
internal timers but by explicitly setting its progress property to a
value between \c 0.0 and \c 1.0.
Inside the AnimationController, we run two NumberAnimation instances in
parallel to move the number pad and the display components simultaneously to
the opposite sides of the view. In addition, we run a SequentialAnimation
instance to scale the number pad during the transition, giving the animation
some depth.
\quotefromfile demos/calqlatr/calqlatr.qml
\skipto AnimationController
\printuntil 1; easing.type
\printuntil }
\printuntil }
\printuntil }
We use the easing curve of the type \c Easing.InOutQuad to accelerate the
motion until halfway and then decelerate it.
\section1 Performing Calculations
The calculator.js file contains definitions for the functions to execute
when users press the digit and operator buttons. To use the functions, we
import calculator.js in the calqlatr.qml file as \c CalcEngine:
\code
import "content/calculator.js" as CalcEngine
\endcode
We can then declare the functions to execute depending on whether the
operator property for a button is set to \c true in NumberPad.qml:
\quotefromfile demos/calqlatr/calqlatr.qml
\skipto operatorPressed
\printuntil digitPressed
When users press a digit or operator, the text from the digit appears on the
display. When they press the equals operator (=), the appropriate
calculation is performed, and the results appear on the display.
\section1 List of Files
\sa {QML Applications}
*/
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