Let specifying the fallback style for custom styles

For example, you can call QQuickStyle::setStyle(":/mycontrols") and
QQuickStyle::setFallbackStyle("Material") to select a custom style so
that the missing files will fallback to the Material style.

Notice that the Material and Universal styles do not contain all files.
For example, the non-visual Control.qml, Container.qml are not duplicated.
For these, we must fallback to the Default style that is guaranteed to
contain them all.

[ChangeLog][Controls] Added support for specifying the fallback style for
custom styles via :/qtquickcontrols2.conf, QT_QUICK_CONTROLS_FALLBACK_STYLE
or QQuickStyle::setFallbackStyle().

Change-Id: I00be1c8c6aaca875ef851c90d018e9b5e2f501b7
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/auto/qquickstyle/tst_qquickstyle.cpp b/tests/auto/qquickstyle/tst_qquickstyle.cpp
index 11ff58e7..15edc67b 100644
--- a/tests/auto/qquickstyle/tst_qquickstyle.cpp
+++ b/tests/auto/qquickstyle/tst_qquickstyle.cpp
@@ -38,15 +38,28 @@
 #include <QtQml/qqmlengine.h>
 #include <QtQml/qqmlcomponent.h>
 #include <QtQuickControls2/qquickstyle.h>
+#include <QtQuickControls2/private/qquickstyle_p.h>
+#include <QtGui/private/qguiapplication_p.h>
 
 class tst_QQuickStyle : public QObject
 {
     Q_OBJECT
 
 private slots:
+    void init();
     void lookup();
+    void commandLineArgument();
+    void environmentVariables();
 };
 
+void tst_QQuickStyle::init()
+{
+    QQuickStylePrivate::reset();
+    QGuiApplicationPrivate::styleOverride.clear();
+    qunsetenv("QT_QUICK_CONTROLS_STYLE");
+    qunsetenv("QT_QUICK_CONTROLS_FALLBACK_STYLE");
+}
+
 void tst_QQuickStyle::lookup()
 {
     QVERIFY(QQuickStyle::name().isEmpty());
@@ -67,6 +80,20 @@ void tst_QQuickStyle::lookup()
     QVERIFY(!QQuickStyle::path().isEmpty());
 }
 
+void tst_QQuickStyle::commandLineArgument()
+{
+    QGuiApplicationPrivate::styleOverride = "CmdLineArgStyle";
+    QCOMPARE(QQuickStyle::name(), QString("CmdLineArgStyle"));
+}
+
+void tst_QQuickStyle::environmentVariables()
+{
+    qputenv("QT_QUICK_CONTROLS_STYLE", "EnvVarStyle");
+    qputenv("QT_QUICK_CONTROLS_FALLBACK_STYLE", "EnvVarFallbackStyle");
+    QCOMPARE(QQuickStyle::name(), QString("EnvVarStyle"));
+    QCOMPARE(QQuickStylePrivate::fallbackStyle(), QString("EnvVarFallbackStyle"));
+}
+
 QTEST_MAIN(tst_QQuickStyle)
 
 #include "tst_qquickstyle.moc"