Android: add support for custom buttons in native MessageDialog helper

New API in QMessageDialogOptions and implementation on Android.

Task-number: QTBUG-35545
Change-Id: I59567251199f220862d01ba76979266379eecd86
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/gui/kernel/qplatformdialoghelper.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -44,6 +44,7 @@
 #include <QtCore/QSharedData>
 #include <QtCore/QSettings>
 #include <QtCore/QUrl>
+#include <QtCore/QVector>
 #include <QtGui/QColor>
 
 #include <algorithm>
@@ -786,7 +787,8 @@ class QMessageDialogOptionsPrivate : public QSharedData
 public:
     QMessageDialogOptionsPrivate() :
         icon(QMessageDialogOptions::NoIcon),
-        buttons(QPlatformDialogHelper::Ok)
+        buttons(QPlatformDialogHelper::Ok),
+        nextCustomButtonId(QPlatformDialogHelper::LastButton + 1)
     {}
 
     QString windowTitle;
@@ -795,6 +797,8 @@ public:
     QString informativeText;
     QString detailedText;
     QPlatformDialogHelper::StandardButtons buttons;
+    QVector<QMessageDialogOptions::CustomButton> customButtons;
+    int nextCustomButtonId;
 };
 
 QMessageDialogOptions::QMessageDialogOptions(QMessageDialogOptionsPrivate *dd)
@@ -886,6 +890,35 @@ QPlatformDialogHelper::StandardButtons QMessageDialogOptions::standardButtons()
     return d->buttons;
 }
 
+int QMessageDialogOptions::addButton(const QString &label, QPlatformDialogHelper::ButtonRole role,
+                                     void *buttonImpl)
+{
+    const CustomButton b(d->nextCustomButtonId++, label, role, buttonImpl);
+    d->customButtons.append(b);
+    return b.id;
+}
+
+static inline bool operator==(const QMessageDialogOptions::CustomButton &a,
+                              const QMessageDialogOptions::CustomButton &b) {
+    return a.id == b.id;
+}
+
+void QMessageDialogOptions::removeButton(int id)
+{
+    d->customButtons.removeOne(CustomButton(id));
+}
+
+const QVector<QMessageDialogOptions::CustomButton> &QMessageDialogOptions::customButtons()
+{
+    return d->customButtons;
+}
+
+const QMessageDialogOptions::CustomButton *QMessageDialogOptions::customButton(int id)
+{
+    int i = d->customButtons.indexOf(CustomButton(id));
+    return (i < 0 ? nullptr : &d->customButtons.at(i));
+}
+
 QPlatformDialogHelper::ButtonRole QPlatformDialogHelper::buttonRole(QPlatformDialogHelper::StandardButton button)
 {
     switch (button) {

src/gui/kernel/qplatformdialoghelper.h

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -460,6 +460,26 @@ public:
     void setStandardButtons(QPlatformDialogHelper::StandardButtons buttons);
     QPlatformDialogHelper::StandardButtons standardButtons() const;
 
+    struct CustomButton {
+        explicit CustomButton(
+                int id = -1, const QString &label = QString(),
+                QPlatformDialogHelper::ButtonRole role = QPlatformDialogHelper::InvalidRole,
+                void *button = nullptr) :
+            label(label), role(role), id(id), button(button)
+        {}
+
+        QString label;
+        QPlatformDialogHelper::ButtonRole role;
+        int id;
+        void *button; // strictly internal use only
+    };
+
+    int addButton(const QString &label, QPlatformDialogHelper::ButtonRole role,
+                  void *buttonImpl = nullptr);
+    void removeButton(int id);
+    const QVector<CustomButton> &customButtons();
+    const CustomButton *customButton(int id);
+
 private:
     QMessageDialogOptionsPrivate *d;
 };

src/plugins/platforms/android/qandroidplatformdialoghelpers.cpp

@@ -1,5 +1,6 @@
 /****************************************************************************
 **
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Copyright (C) 2013 BogDan Vatra <bogdan@kde.org>
 ** Contact: https://www.qt.io/licensing/
 **
@@ -117,6 +118,15 @@ bool QAndroidPlatformMessageDialogHelper::show(Qt::WindowFlags windowFlags
 
 void QAndroidPlatformMessageDialogHelper::addButtons(QSharedPointer<QMessageDialogOptions> opt, ButtonRole role)
 {
+    for (const QMessageDialogOptions::CustomButton &b : opt->customButtons()) {
+        if (b.role == role) {
+            QString label = b.label;
+            label.remove(QChar('&'));
+            m_javaMessageDialog.callMethod<void>("addButton", "(ILjava/lang/String;)V", b.id,
+                                                 QJNIObjectPrivate::fromString(label).object());
+        }
+    }
+
     for (int i = QPlatformDialogHelper::FirstButton; i < QPlatformDialogHelper::LastButton; i<<=1) {
         StandardButton b = static_cast<StandardButton>(i);
         if (buttonRole(b) == role && (opt->standardButtons() & i)) {
@@ -144,6 +154,12 @@ void QAndroidPlatformMessageDialogHelper::dialogResult(int buttonID)
 
     QPlatformDialogHelper::StandardButton standardButton = static_cast<QPlatformDialogHelper::StandardButton>(buttonID);
     QPlatformDialogHelper::ButtonRole role = QPlatformDialogHelper::buttonRole(standardButton);
+    if (buttonID > QPlatformDialogHelper::LastButton) {
+        const QMessageDialogOptions::CustomButton *custom = options()->customButton(buttonID);
+        Q_ASSERT(custom);
+        role = custom->role;
+    }
+
     emit clicked(standardButton, role);
 }
 

src/widgets/dialogs/qmessagebox.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -64,6 +64,7 @@
 #include <QtGui/qfont.h>
 #include <QtGui/qfontmetrics.h>
 #include <QtGui/qclipboard.h>
+#include "private/qabstractbutton_p.h"
 #include <private/qdesktopwidget_p.h>
 
 #ifdef Q_OS_WIN
@@ -492,9 +493,17 @@ void QMessageBoxPrivate::_q_buttonClicked(QAbstractButton *button)
 
 void QMessageBoxPrivate::_q_clicked(QPlatformDialogHelper::StandardButton button, QPlatformDialogHelper::ButtonRole role)
 {
-    Q_UNUSED(role);
     Q_Q(QMessageBox);
-    q->done(button);
+    if (button > QPlatformDialogHelper::LastButton) {
+        // It's a custom button, and the QPushButton in options is just a proxy
+        // for the button on the platform dialog.  Simulate the user clicking it.
+        clickedButton = static_cast<QAbstractButton *>(options->customButton(button)->button);
+        Q_ASSERT(clickedButton);
+        clickedButton->click();
+        q->done(role);
+    } else {
+        q->done(button);
+    }
 }
 
 /*!
@@ -831,6 +840,8 @@ void QMessageBox::addButton(QAbstractButton *button, ButtonRole role)
     if (!button)
         return;
     removeButton(button);
+    d->options->addButton(button->text(), static_cast<QPlatformDialogHelper::ButtonRole>(role),
+                          button);
     d->buttonBox->addButton(button, (QDialogButtonBox::ButtonRole)role);
     d->customButtonList.append(button);
     d->autoAddOkButton = false;
@@ -2678,7 +2689,11 @@ void QMessageBoxPrivate::helperPrepareShow(QPlatformDialogHelper *)
 void QMessageBoxPrivate::helperDone(QDialog::DialogCode code, QPlatformDialogHelper *)
 {
     Q_Q(QMessageBox);
-    clickedButton = q->button(QMessageBox::StandardButton(code));
+    QAbstractButton *button = q->button(QMessageBox::StandardButton(code));
+    // If it was a custom button, a custom ID was used, so we won't get a valid pointer here.
+    // In that case, clickedButton has already been set in _q_buttonClicked.
+    if (button)
+        clickedButton = button;
 }
 
 /*!