Android: handle keyPress event for Key_Back

Added logic so that accepting either the press or the release will
keep the app running. This makes it possible to use the onBackPressed
functionality in QML.

This functionality is only intended for running in a complete Android
environment, so make sure that we don't terminate the application in
the NO_SDK case.

Task-number: QTBUG-30803

Change-Id: I2546eea73bf6a6ee8b196125b7556479b9b10a9c
Reviewed-by: BogDan Vatra <bogdan@kde.org>

1 files changed, 18 insertions, 23 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index d254f7c9bc..2e6000625e 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -1666,41 +1666,36 @@ void QGuiApplicationPrivate::processKeyEvent(QWindowSystemInterfacePrivate::KeyE
     QWindow *window = e->window.data();
     modifier_buttons = e->modifiers;
     if (e->nullWindow
-#ifdef Q_OS_ANDROID
-           || (e->keyType == QEvent::KeyRelease && e->key == Qt::Key_Back) || e->key == Qt::Key_Menu
+#if defined(Q_OS_ANDROID) && !defined(Q_OS_ANDROID_NO_SDK)
+           || e->key == Qt::Key_Back || e->key == Qt::Key_Menu
 #endif
             ) {
         window = QGuiApplication::focusWindow();
     }
-    if (!window
-#ifdef Q_OS_ANDROID
-           && e->keyType != QEvent::KeyRelease && e->key != Qt::Key_Back
-#endif
-            ) {
-        return;
-    }
-    if (window && window->d_func()->blockedByModalWindow) {
-        // a modal window is blocking this window, don't allow key events through
-        return;
-    }
 
     QKeyEvent ev(e->keyType, e->key, e->modifiers,
                  e->nativeScanCode, e->nativeVirtualKey, e->nativeModifiers,
                  e->unicode, e->repeat, e->repeatCount);
     ev.setTimestamp(e->timestamp);
 
-#ifdef Q_OS_ANDROID
-    if (e->keyType == QEvent::KeyRelease && e->key == Qt::Key_Back) {
-        if (!window) {
+    // only deliver key events when we have a window, and no modal window is blocking this window
+
+    if (window && !window->d_func()->blockedByModalWindow)
+        QGuiApplication::sendSpontaneousEvent(window, &ev);
+#if defined(Q_OS_ANDROID) && !defined(Q_OS_ANDROID_NO_SDK)
+    else
+        ev.setAccepted(false);
+
+    static bool backKeyPressAccepted = false;
+    if (e->keyType == QEvent::KeyPress) {
+        backKeyPressAccepted = e->key == Qt::Key_Back && ev.isAccepted();
+    } else if (e->keyType == QEvent::KeyRelease && e->key == Qt::Key_Back && !backKeyPressAccepted && !ev.isAccepted()) {
+        if (!window)
             qApp->quit();
-        } else {
-            QGuiApplication::sendEvent(window, &ev);
-            if (!ev.isAccepted() && e->key == Qt::Key_Back)
-                QWindowSystemInterface::handleCloseEvent(window);
-        }
-    } else
+        else
+            QWindowSystemInterface::handleCloseEvent(window);
+    }
 #endif
-        QGuiApplication::sendSpontaneousEvent(window, &ev);
 }
 
 void QGuiApplicationPrivate::processEnterEvent(QWindowSystemInterfacePrivate::EnterEvent *e)