From 78b3aed3264439cd95ca23a47e53e15b769a58ae Mon Sep 17 00:00:00 2001 From: Alan Alpert Date: Wed, 23 Jan 2013 15:17:27 -0800 Subject: Move QML types to types folder The QtQml module has gain a bunch of QML types cluttering up the qml folder. Moving them to types organizes them a bit better. Change-Id: I570884c00f4abc48f4f1aea048bf002bc70223f3 Reviewed-by: Gabriel de Dietrich Reviewed-by: Lars Knoll --- src/qml/types/qqmlbind.cpp | 310 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 310 insertions(+) create mode 100644 src/qml/types/qqmlbind.cpp (limited to 'src/qml/types/qqmlbind.cpp') diff --git a/src/qml/types/qqmlbind.cpp b/src/qml/types/qqmlbind.cpp new file mode 100644 index 0000000000..fcb3079891 --- /dev/null +++ b/src/qml/types/qqmlbind.cpp @@ -0,0 +1,310 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QtQml module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** 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 Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qqmlbind_p.h" + +#include +#include +#include +#include + +#include +#include +#include +#include + +#include +#include + +#include + +QT_BEGIN_NAMESPACE + +class QQmlBindPrivate : public QObjectPrivate +{ +public: + QQmlBindPrivate() : componentComplete(true), obj(0), prevBind(0) {} + ~QQmlBindPrivate() { if (prevBind) prevBind->destroy(); } + + QQmlNullableValue when; + bool componentComplete; + QQmlGuard obj; + QString propName; + QQmlNullableValue value; + QQmlProperty prop; + QQmlAbstractBinding *prevBind; +}; + + +/*! + \qmltype Binding + \instantiates QQmlBind + \inqmlmodule QtQml 2 + \ingroup qtquick-interceptors + \brief Enables the arbitrary creation of property bindings + + \section1 Binding to an inaccessible property + + Sometimes it is necessary to bind to a property of an object that wasn't + directly instantiated by QML - generally a property of a class exported + to QML by C++. In these cases, regular property binding doesn't work. Binding + allows you to bind any value to any property. + + For example, imagine a C++ application that maps an "app.enteredText" + property into QML. You could use Binding to update the enteredText property + like this. + \code + TextEdit { id: myTextField; text: "Please type here..." } + Binding { target: app; property: "enteredText"; value: myTextField.text } + \endcode + Whenever the text in the TextEdit is updated, the C++ property will be + updated also. + + \section1 "Single-branch" conditional binding + + In some circumstances you may want to control the value of a property + only when a certain condition is true (and relinquish control in all + other circumstances). This often isn't possible to accomplish with a direct + binding, as you need to supply values for all possible branches. + + \code + // produces warning: "Unable to assign [undefined] to double value" + value: if (mouse.pressed) mouse.mouseX + \endcode + + The above example will produce a warning whenever we release the mouse, as the value + of the binding is undefined when the mouse isn't pressed. We can use the Binding + type to rewrite the above code and avoid the warning. + + \qml + Binding on value { + when: mouse.pressed + value: mouse.mouseX + } + \endqml + + The Binding type will also restore any previously set direct bindings on + the property. In that sense, it functions much like a simplified State. + + \qml + // this is equivalent to the above Binding + State { + name: "pressed" + when: mouse.pressed + PropertyChanges { + target: obj + value: mouse.mouseX + } + } + \endqml + + If the binding target or binding property is changed, the bound value is + immediately pushed onto the new target. + + \sa QtQml +*/ +QQmlBind::QQmlBind(QObject *parent) + : QObject(*(new QQmlBindPrivate), parent) +{ +} + +QQmlBind::~QQmlBind() +{ +} + +/*! + \qmlproperty bool QtQml2::Binding::when + + This property holds when the binding is active. + This should be set to an expression that evaluates to true when you want the binding to be active. + + \code + Binding { + target: contactName; property: 'text' + value: name; when: list.ListView.isCurrentItem + } + \endcode + + When the binding becomes inactive again, any direct bindings that were previously + set on the property will be restored. +*/ +bool QQmlBind::when() const +{ + Q_D(const QQmlBind); + return d->when; +} + +void QQmlBind::setWhen(bool v) +{ + Q_D(QQmlBind); + if (!d->when.isNull && d->when == v) + return; + + d->when = v; + eval(); +} + +/*! + \qmlproperty Object QtQml2::Binding::target + + The object to be updated. +*/ +QObject *QQmlBind::object() +{ + Q_D(const QQmlBind); + return d->obj; +} + +void QQmlBind::setObject(QObject *obj) +{ + Q_D(QQmlBind); + if (d->obj && d->when.isValid() && d->when) { + /* if we switch the object at runtime, we need to restore the + previous binding on the old object before continuing */ + d->when = false; + eval(); + d->when = true; + } + d->obj = obj; + if (d->componentComplete) + d->prop = QQmlProperty(d->obj, d->propName); + eval(); +} + +/*! + \qmlproperty string QtQml2::Binding::property + + The property to be updated. +*/ +QString QQmlBind::property() const +{ + Q_D(const QQmlBind); + return d->propName; +} + +void QQmlBind::setProperty(const QString &p) +{ + Q_D(QQmlBind); + if (!d->propName.isEmpty() && d->when.isValid() && d->when) { + /* if we switch the property name at runtime, we need to restore the + previous binding on the old object before continuing */ + d->when = false; + eval(); + d->when = true; + } + d->propName = p; + if (d->componentComplete) + d->prop = QQmlProperty(d->obj, d->propName); + eval(); +} + +/*! + \qmlproperty any QtQml2::Binding::value + + The value to be set on the target object and property. This can be a + constant (which isn't very useful), or a bound expression. +*/ +QVariant QQmlBind::value() const +{ + Q_D(const QQmlBind); + return d->value.value; +} + +void QQmlBind::setValue(const QVariant &v) +{ + Q_D(QQmlBind); + d->value = v; + eval(); +} + +void QQmlBind::setTarget(const QQmlProperty &p) +{ + Q_D(QQmlBind); + d->prop = p; +} + +void QQmlBind::classBegin() +{ + Q_D(QQmlBind); + d->componentComplete = false; +} + +void QQmlBind::componentComplete() +{ + Q_D(QQmlBind); + d->componentComplete = true; + if (!d->prop.isValid()) + d->prop = QQmlProperty(d->obj, d->propName); + eval(); +} + +void QQmlBind::eval() +{ + Q_D(QQmlBind); + if (!d->prop.isValid() || d->value.isNull || !d->componentComplete) + return; + + if (d->when.isValid()) { + if (!d->when) { + //restore any previous binding + if (d->prevBind) { + QQmlAbstractBinding *tmp = d->prevBind; + d->prevBind = 0; + tmp = QQmlPropertyPrivate::setBinding(d->prop, tmp); + if (tmp) //should this ever be true? + tmp->destroy(); + } + return; + } + + //save any set binding for restoration + QQmlAbstractBinding *tmp; + tmp = QQmlPropertyPrivate::setBinding(d->prop, 0); + if (tmp && d->prevBind) + tmp->destroy(); + else if (!d->prevBind) + d->prevBind = tmp; + } + + d->prop.write(d->value.value); +} + +QT_END_NAMESPACE -- cgit v1.2.3