Add support to match against QObject properties in DelegateChooser

Views could use an array of QObject instances as a model, as an alterative to a
QAIM subclass; but DelegateChooser only supported querying the value based on the
model role name. Now a QObject property name can also be used as roleValue.

[ChangeLog][QtQuick][Item Views] DelegateChooser now supports using a property name
as roleValue when an array of QObject instances is used as the model for a view.

Fixes: QTBUG-81580
Change-Id: I3e5b57ce0456520667e342741efbe46417f0843c
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

3 files changed, 123 insertions, 3 deletions

diff --git a/src/imports/labsmodels/qqmldelegatecomponent.cpp b/src/imports/labsmodels/qqmldelegatecomponent.cpp
index 4698287fe3..aaf3fea5da 100644
--- a/src/imports/labsmodels/qqmldelegatecomponent.cpp
+++ b/src/imports/labsmodels/qqmldelegatecomponent.cpp
@@ -218,7 +218,7 @@ bool QQmlDelegateChoice::match(int row, int column, const QVariant &value) const
 
 /*!
     \qmlproperty string QtQml.Models::DelegateChooser::role
-    This property holds the role used to determine the delegate for a given model item.
+    This property holds the role or the property name used to determine the delegate for a given model item.
 
     \sa DelegateChoice
 */
@@ -289,9 +289,15 @@ QQmlComponent *QQmlDelegateChooser::delegate(QQmlAdaptorModel *adaptorModel, int
         v = value(adaptorModel, row, column, m_role);
     if (!v.isValid()) { // check if the row only has modelData, for example if the row is a QVariantMap
         v = value(adaptorModel, row, column, QStringLiteral("modelData"));
-        if (v.isValid())
-            v = v.toMap().value(m_role);
+
+        if (v.isValid()) {
+            if (v.canConvert(QMetaType::QVariantMap))
+                v = v.toMap().value(m_role);
+            else if (v.canConvert(QMetaType::QObjectStar))
+                v = v.value<QObject*>()->property(m_role.toUtf8());
+        }
     }
+
     // loop through choices, finding first one that fits
     for (int i = 0; i < m_choices.count(); ++i) {
         const QQmlDelegateChoice *choice = m_choices.at(i);
diff --git a/tests/auto/qmltest/listview/data/MultiDelegate3.qml b/tests/auto/qmltest/listview/data/MultiDelegate3.qml
new file mode 100644
index 0000000000..75116e0f9b
--- /dev/null
+++ b/tests/auto/qmltest/listview/data/MultiDelegate3.qml
@@ -0,0 +1,97 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+import QtQml.Models 2.12
+import Qt.labs.qmlmodels 1.0
+
+ListView {
+    width: 400
+    height: 400
+
+    property var item1: QtObject {
+        property string dataType: "rect"
+        property color color: "red"
+    }
+    property var item2: QtObject {
+        property string dataType: "text"
+        property string text: "Hello world"
+    }
+    model: [ item1, item2 ]
+
+    delegate: DelegateChooser {
+        role: "dataType"
+        DelegateChoice {
+            roleValue: "rect"
+            delegate: Rectangle {
+                width: parent.width
+                height: 50
+                color: modelData.color
+            }
+        }
+        DelegateChoice {
+            roleValue: "text"
+            delegate: Text {
+                width: parent.width
+                height: 50
+                horizontalAlignment: Text.AlignHCenter
+                verticalAlignment: Text.AlignVCenter
+                text: modelData.text
+            }
+        }
+
+        DelegateChoice {
+            delegate: Item {
+                    width: parent.width
+                    height: 50
+            }
+        }
+    }
+}
diff --git a/tests/auto/qmltest/listview/tst_listview.qml b/tests/auto/qmltest/listview/tst_listview.qml
index 5e9bb22e8e..bea6b45c3a 100644
--- a/tests/auto/qmltest/listview/tst_listview.qml
+++ b/tests/auto/qmltest/listview/tst_listview.qml
@@ -213,6 +213,10 @@ Item {
         id: multiDelegate2
     }
 
+    MultiDelegate3 {
+        id: multiDelegate3
+    }
+
     TestCase {
         name: "ListView"
         when: windowShown
@@ -414,5 +418,18 @@ Item {
             var delegate = multiDelegate2.itemAt(10, row.y)
             compare(delegate.choiceType, row.type)
         }
+
+        function test_multipleDelegates3_data() {
+            return [
+                { y: 25, type: "Rectangle", property: "color", value: "#ff0000" },
+                { y: 75, type: "Text", property: "text", value: "Hello world" }
+            ]
+        }
+
+        function test_multipleDelegates3(row) {
+            var delegate = multiDelegate3.itemAt(10, row.y)
+            verify(delegate.toString().includes(row.type))
+            compare(delegate[row.property], row.value)
+        }
     }
 }