1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** 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, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "private/qdeclarativebind_p.h"
#include "private/qdeclarativenullablevalue_p_p.h"
#include <qdeclarativeengine.h>
#include <qdeclarativecontext.h>
#include <qdeclarativeproperty.h>
#include <QtCore/qfile.h>
#include <QtCore/qdebug.h>
#include <QtScript/qscriptvalue.h>
#include <QtScript/qscriptcontext.h>
#include <QtScript/qscriptengine.h>
#include <private/qobject_p.h>
QT_BEGIN_NAMESPACE
class QDeclarativeBindPrivate : public QObjectPrivate
{
public:
QDeclarativeBindPrivate() : when(true), componentComplete(true), obj(0) {}
bool when : 1;
bool componentComplete : 1;
QObject *obj;
QString prop;
QDeclarativeNullableValue<QVariant> value;
};
/*!
\qmlclass Binding QDeclarativeBind
\ingroup qml-working-with-data
\since 4.7
\brief The Binding element allows arbitrary property bindings to be created.
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.
If the binding target or binding property is changed, the bound value is
immediately pushed onto the new target.
\sa QtDeclarative
*/
QDeclarativeBind::QDeclarativeBind(QObject *parent)
: QObject(*(new QDeclarativeBindPrivate), parent)
{
}
QDeclarativeBind::~QDeclarativeBind()
{
}
/*!
\qmlproperty bool 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
*/
bool QDeclarativeBind::when() const
{
Q_D(const QDeclarativeBind);
return d->when;
}
void QDeclarativeBind::setWhen(bool v)
{
Q_D(QDeclarativeBind);
d->when = v;
eval();
}
/*!
\qmlproperty Object Binding::target
The object to be updated.
*/
QObject *QDeclarativeBind::object()
{
Q_D(const QDeclarativeBind);
return d->obj;
}
void QDeclarativeBind::setObject(QObject *obj)
{
Q_D(QDeclarativeBind);
d->obj = obj;
eval();
}
/*!
\qmlproperty string Binding::property
The property to be updated.
*/
QString QDeclarativeBind::property() const
{
Q_D(const QDeclarativeBind);
return d->prop;
}
void QDeclarativeBind::setProperty(const QString &p)
{
Q_D(QDeclarativeBind);
d->prop = p;
eval();
}
/*!
\qmlproperty any 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 QDeclarativeBind::value() const
{
Q_D(const QDeclarativeBind);
return d->value.value;
}
void QDeclarativeBind::setValue(const QVariant &v)
{
Q_D(QDeclarativeBind);
d->value.value = v;
d->value.isNull = false;
eval();
}
void QDeclarativeBind::classBegin()
{
Q_D(QDeclarativeBind);
d->componentComplete = false;
}
void QDeclarativeBind::componentComplete()
{
Q_D(QDeclarativeBind);
d->componentComplete = true;
eval();
}
void QDeclarativeBind::eval()
{
Q_D(QDeclarativeBind);
if (!d->obj || d->value.isNull || !d->when || !d->componentComplete)
return;
QDeclarativeProperty prop(d->obj, d->prop);
prop.write(d->value.value);
}
QT_END_NAMESPACE
|
