Add AbstractButton::autoExclusive

This feature is adopted from QtWidgets' QAbstractButton. It's no longer
necessary to create an ExclusiveGroup to manage a simple list of radio
buttons:

    Column {
        RadioButton { text: "Option 1" }
        RadioButton { text: "Option 2" }
    }

Change-Id: Ib4cb718c3b3034c9c956b2f23db4b06b00547b8e
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>

6 files changed, 173 insertions, 16 deletions

diff --git a/src/templates/qquickabstractbutton.cpp b/src/templates/qquickabstractbutton.cpp
index 849d2340..0b211e46 100644
--- a/src/templates/qquickabstractbutton.cpp
+++ b/src/templates/qquickabstractbutton.cpp
@@ -36,9 +36,11 @@
 
 #include "qquickabstractbutton_p.h"
 #include "qquickabstractbutton_p_p.h"
+#include "qquickexclusivegroup_p.h"
 
 #include <QtGui/qguiapplication.h>
 #include <QtQuick/private/qquickevents_p_p.h>
+#include <QtQml/qqmllist.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -100,7 +102,7 @@ static const int AUTO_REPEAT_INTERVAL = 100;
 */
 
 QQuickAbstractButtonPrivate::QQuickAbstractButtonPrivate() :
-    pressed(false), checked(false), checkable(false), exclusive(false), autoRepeat(false),
+    pressed(false), checked(false), checkable(false), autoExclusive(false), autoRepeat(false),
     delayTimer(0), repeatTimer(0), repeatButton(Qt::NoButton), label(Q_NULLPTR), indicator(Q_NULLPTR)
 {
 }
@@ -132,6 +134,60 @@ void QQuickAbstractButtonPrivate::stopPressRepeat()
     }
 }
 
+QQuickExclusiveGroup *QQuickAbstractButtonPrivate::exclusiveGroup() const
+{
+    Q_Q(const QQuickAbstractButton);
+    QQuickExclusiveGroupAttached *attached = qobject_cast<QQuickExclusiveGroupAttached *>(qmlAttachedPropertiesObject<QQuickExclusiveGroup>(q, false));
+    if (attached)
+        return attached->group();
+    return Q_NULLPTR;
+}
+
+QQuickAbstractButton *QQuickAbstractButtonPrivate::findCheckedButton() const
+{
+    Q_Q(const QQuickAbstractButton);
+    QQuickExclusiveGroup *group = exclusiveGroup();
+    if (group)
+        return qobject_cast<QQuickAbstractButton *>(group->current());
+
+    QList<QQuickAbstractButton *> buttons = findExclusiveButtons();
+    // TODO: A singular QRadioButton can be unchecked, which seems logical,
+    // because there's nothing to be exclusive with. However, a RadioButton
+    // from QtQuick.Controls 1.x can never be unchecked, which is the behavior
+    // that QQuickRadioButton adopted. Uncommenting the following count check
+    // gives the QRadioButton behavior. Notice that tst_radiobutton.qml needs
+    // to be updated.
+    if (!autoExclusive /*|| buttons.count() == 1*/)
+        return Q_NULLPTR;
+
+    foreach (QQuickAbstractButton *button, buttons) {
+        if (button->isChecked() && button != q)
+            return button;
+    }
+    return checked ? const_cast<QQuickAbstractButton *>(q) : Q_NULLPTR;
+}
+
+QList<QQuickAbstractButton *> QQuickAbstractButtonPrivate::findExclusiveButtons() const
+{
+    QList<QQuickAbstractButton *> buttons;
+    QQuickExclusiveGroup *group = exclusiveGroup();
+    if (group) {
+        QQmlListProperty<QObject> checkables = group->checkables();
+        int count = checkables.count(&checkables);
+        for (int i = 0; i < count; ++i) {
+            QQuickAbstractButton *button = qobject_cast<QQuickAbstractButton *>(checkables.at(&checkables, i));
+            if (button)
+                buttons += button;
+        }
+    } else if (parentItem) {
+        foreach (QQuickAbstractButton *button, parentItem->findChildren<QQuickAbstractButton *>()) {
+            if (button->autoExclusive() && !button->d_func()->exclusiveGroup())
+                buttons += button;
+        }
+    }
+    return buttons;
+}
+
 QQuickAbstractButton::QQuickAbstractButton(QQuickItem *parent) :
     QQuickControl(*(new QQuickAbstractButtonPrivate), parent)
 {
@@ -236,16 +292,33 @@ void QQuickAbstractButton::setCheckable(bool checkable)
     }
 }
 
-bool QQuickAbstractButton::isExclusive() const
+/*!
+    \qmlproperty bool Qt.labs.controls::AbstractButton::autoExclusive
+
+    This property holds whether auto-exclusivity is enabled.
+
+    If auto-exclusivity is enabled, checkable buttons that belong to the same
+    parent item behave as if they were part of the same ExclusiveGroup. Only
+    one button can be checked at any time; checking another button automatically
+    unchecks the previously checked one.
+
+    \note The property has no effect on buttons that belong to an ExclusiveGroup.
+
+    RadioButton and TabButton are auto-exclusive by default.
+*/
+bool QQuickAbstractButton::autoExclusive() const
 {
     Q_D(const QQuickAbstractButton);
-    return d->exclusive;
+    return d->autoExclusive;
 }
 
-void QQuickAbstractButton::setExclusive(bool exclusive)
+void QQuickAbstractButton::setAutoExclusive(bool exclusive)
 {
     Q_D(QQuickAbstractButton);
-    d->exclusive = exclusive;
+    if (d->autoExclusive != exclusive) {
+        d->autoExclusive = exclusive;
+        emit autoExclusiveChanged();
+    }
 }
 
 /*!
@@ -471,13 +544,19 @@ void QQuickAbstractButton::timerEvent(QTimerEvent *event)
 
 void QQuickAbstractButton::checkStateSet()
 {
+    Q_D(QQuickAbstractButton);
+    if (d->checked) {
+        QQuickAbstractButton *button = d->findCheckedButton();
+        if (button && button != this)
+            button->setChecked(false);
+    }
 }
 
 void QQuickAbstractButton::nextCheckState()
 {
     Q_D(QQuickAbstractButton);
-    if (d->checkable)
-        setChecked(d->exclusive || !d->checked);
+    if (d->checkable && (!d->checked || d->findCheckedButton() != this))
+        setChecked(!d->checked);
 }
 
 #ifndef QT_NO_ACCESSIBILITY
diff --git a/src/templates/qquickabstractbutton_p.h b/src/templates/qquickabstractbutton_p.h
index 5ab24a23..53d17af3 100644
--- a/src/templates/qquickabstractbutton_p.h
+++ b/src/templates/qquickabstractbutton_p.h
@@ -62,6 +62,7 @@ class Q_LABSTEMPLATES_EXPORT QQuickAbstractButton : public QQuickControl
     Q_PROPERTY(bool pressed READ isPressed WRITE setPressed NOTIFY pressedChanged FINAL)
     Q_PROPERTY(bool checked READ isChecked WRITE setChecked NOTIFY checkedChanged FINAL)
     Q_PROPERTY(bool checkable READ isCheckable WRITE setCheckable NOTIFY checkableChanged FINAL)
+    Q_PROPERTY(bool autoExclusive READ autoExclusive WRITE setAutoExclusive NOTIFY autoExclusiveChanged FINAL)
     Q_PROPERTY(bool autoRepeat READ autoRepeat WRITE setAutoRepeat NOTIFY autoRepeatChanged FINAL)
     Q_PROPERTY(QQuickItem *indicator READ indicator WRITE setIndicator NOTIFY indicatorChanged FINAL)
     Q_PROPERTY(QQuickItem *label READ label WRITE setLabel NOTIFY labelChanged FINAL)
@@ -81,8 +82,8 @@ public:
     bool isCheckable() const;
     void setCheckable(bool checkable);
 
-    bool isExclusive() const;
-    void setExclusive(bool exclusive);
+    bool autoExclusive() const;
+    void setAutoExclusive(bool exclusive);
 
     bool autoRepeat() const;
     void setAutoRepeat(bool repeat);
@@ -106,6 +107,7 @@ Q_SIGNALS:
     void pressedChanged();
     void checkedChanged();
     void checkableChanged();
+    void autoExclusiveChanged();
     void autoRepeatChanged();
     void indicatorChanged();
     void labelChanged();
diff --git a/src/templates/qquickabstractbutton_p_p.h b/src/templates/qquickabstractbutton_p_p.h
index bfdadb19..dfa87e7f 100644
--- a/src/templates/qquickabstractbutton_p_p.h
+++ b/src/templates/qquickabstractbutton_p_p.h
@@ -52,6 +52,9 @@
 
 QT_BEGIN_NAMESPACE
 
+class QQuickAbstractButton;
+class QQuickExclusiveGroup;
+
 class QQuickAbstractButtonPrivate : public QQuickControlPrivate
 {
     Q_DECLARE_PUBLIC(QQuickAbstractButton)
@@ -63,11 +66,15 @@ public:
     void startPressRepeat();
     void stopPressRepeat();
 
+    QQuickExclusiveGroup *exclusiveGroup() const;
+    QQuickAbstractButton *findCheckedButton() const;
+    QList<QQuickAbstractButton *> findExclusiveButtons() const;
+
     QString text;
     bool pressed;
     bool checked;
     bool checkable;
-    bool exclusive;
+    bool autoExclusive;
     bool autoRepeat;
     int delayTimer;
     int repeatTimer;
diff --git a/src/templates/qquickradiobutton.cpp b/src/templates/qquickradiobutton.cpp
index 7a94248a..92a14394 100644
--- a/src/templates/qquickradiobutton.cpp
+++ b/src/templates/qquickradiobutton.cpp
@@ -61,21 +61,22 @@ QT_BEGIN_NAMESPACE
          \li A radio button that is disabled.
     \endtable
 
+    Radio buttons are \l {AbstractButton::autoExclusive}{auto-exclusive}
+    by default. Only one button can be checked at any time amongst radio
+    buttons that belong to the same parent item; checking another button
+    automatically unchecks the previously checked one.
+
     \code
     ColumnLayout {
-        ExclusiveGroup { id: group }
         RadioButton {
             checked: true
             text: qsTr("First")
-            ExclusiveGroup.group: group
         }
         RadioButton {
             text: qsTr("Second")
-            ExclusiveGroup.group: group
         }
         RadioButton {
             text: qsTr("Third")
-            ExclusiveGroup.group: group
         }
     }
     \endcode
@@ -87,7 +88,7 @@ QQuickRadioButton::QQuickRadioButton(QQuickItem *parent) :
     QQuickAbstractButton(parent)
 {
     setCheckable(true);
-    setExclusive(true);
+    setAutoExclusive(true);
 }
 
 #ifndef QT_NO_ACCESSIBILITY
diff --git a/src/templates/qquicktabbutton.cpp b/src/templates/qquicktabbutton.cpp
index a301cc62..23e8a221 100644
--- a/src/templates/qquicktabbutton.cpp
+++ b/src/templates/qquicktabbutton.cpp
@@ -59,7 +59,7 @@ QQuickTabButton::QQuickTabButton(QQuickItem *parent) :
     QQuickAbstractButton(parent)
 {
     setCheckable(true);
-    setExclusive(true);
+    setAutoExclusive(true);
 }
 
 #ifndef QT_NO_ACCESSIBILITY
diff --git a/tests/auto/controls/data/tst_radiobutton.qml b/tests/auto/controls/data/tst_radiobutton.qml
index d76a8c38..2df3542d 100644
--- a/tests/auto/controls/data/tst_radiobutton.qml
+++ b/tests/auto/controls/data/tst_radiobutton.qml
@@ -225,4 +225,72 @@ TestCase {
 
         container.destroy()
     }
+
+    Component {
+        id: radioButtonGroup
+        Column {
+            // auto-exclusive buttons behave as if they were in their own exclusive group
+            RadioButton { }
+            RadioButton { }
+
+            // explicitly grouped buttons are only exclusive with each other, not with
+            // auto-exclusive buttons, and the autoExclusive property is ignored
+            ExclusiveGroup { id: eg }
+            RadioButton { ExclusiveGroup.group: eg }
+            RadioButton { ExclusiveGroup.group: eg; autoExclusive: false }
+
+            // non-exclusive buttons don't affect the others
+            RadioButton { autoExclusive: false }
+            RadioButton { autoExclusive: false }
+        }
+    }
+
+    function test_autoExclusive() {
+        var container = radioButtonGroup.createObject(testCase)
+        compare(container.children.length, 6)
+
+        var checkStates = [false, false, false, false, false, false]
+        for (var i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[0].checked = true
+        checkStates[0] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[1].checked = true
+        checkStates[0] = false
+        checkStates[1] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[2].checked = true
+        checkStates[2] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[3].checked = true
+        checkStates[2] = false
+        checkStates[3] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[4].checked = true
+        checkStates[4] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[5].checked = true
+        checkStates[5] = true
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.children[0].checked = true
+        checkStates[0] = true
+        checkStates[1] = false
+        for (i = 0; i < 6; ++i)
+            compare(container.children[i].checked, checkStates[i])
+
+        container.destroy()
+    }
 }