[lookandfeel] Add virtual keyboard to the LockScreen

Summary:
This change integrates QtVirtualKeyboard into the Lock screen UI.

A new button is added to the bottom row to toggle the appearance of the
virtual keyboard. The actual keyboard is integrated through a Loader so
that not having qtvirtualkeyboard plugin installed results in a graceful
error instead of a failing lock screen.

When the virtual keyboard is shown the remaining UI shifts upwards. This
is done through adding the stack view into a ColumnLayout. Unfortunately
this can result in an overlap with the clock. This needs some general
improvement as on e.g. my system the clock is never really visible.

To have the virtual keyboard working in the lock screen one also needs
another change to kscreenlocker_greet.

Test Plan: See screenshots

Reviewers: #plasma

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D4870

lookandfeel/contents/components/SessionManagementScreen.qml

@@ -66,7 +66,7 @@ Item {
 
     UserList {
         id: userListView
-        visible: showUserList
+        visible: showUserList && y > 0
         anchors {
             bottom: parent.verticalCenter
             left: parent.left

lookandfeel/contents/lockscreen/LockScreenUi.qml

@@ -132,56 +132,75 @@ PlasmaCore.ColorScope {
             }
         }
 
-        StackView {
-            id: mainStack
+        ColumnLayout {
             anchors.fill: parent
-            focus: true //StackView is an implicit focus scope, so we need to give this focus so the item inside will have it
+            StackView {
+                id: mainStack
+                Layout.fillWidth: true
+                Layout.fillHeight: true
+                focus: true //StackView is an implicit focus scope, so we need to give this focus so the item inside will have it
 
-            initialItem: MainBlock {
-                id: mainBlock
+                initialItem: MainBlock {
+                    id: mainBlock
 
-                Stack.onStatusChanged: {
-                    // prepare for presenting again to the user
-                    if (Stack.status == Stack.Activating) {
-                        mainPasswordBox.remove(0, mainPasswordBox.length)
-                        mainPasswordBox.focus = true
+                    Stack.onStatusChanged: {
+                        // prepare for presenting again to the user
+                        if (Stack.status == Stack.Activating) {
+                            mainPasswordBox.remove(0, mainPasswordBox.length)
+                            mainPasswordBox.focus = true
+                        }
                     }
-                }
-                userListModel: users
-                notificationMessage: {
-                    var text = ""
-                    if (keystateSource.data["Caps Lock"]["Locked"]) {
-                        text += i18nd("plasma_lookandfeel_org.kde.lookandfeel","Caps Lock is on")
-                        if (root.notification) {
-                            text += " • "
+                    userListModel: users
+                    notificationMessage: {
+                        var text = ""
+                        if (keystateSource.data["Caps Lock"]["Locked"]) {
+                            text += i18nd("plasma_lookandfeel_org.kde.lookandfeel","Caps Lock is on")
+                            if (root.notification) {
+                                text += " • "
+                            }
                         }
+                        text += root.notification
+                        return text
                     }
-                    text += root.notification
-                    return text
-                }
-
-                onLoginRequest: {
-                    root.notification = ""
-                    authenticator.tryUnlock(password)
-                }
 
-                actionItems: [
-                    ActionButton {
-                        text: i18nd("plasma_lookandfeel_org.kde.lookandfeel", "Switch User")
-                        iconSource: "system-switch-user"
-                        onClicked: mainStack.push(switchSessionPage)
-                        // the current session isn't listed in the model, hence a check for greater than zero, not one
-                        visible: (sessionsModel.count > 0 || sessionsModel.canStartNewSession) && sessionsModel.canSwitchUser
+                    onLoginRequest: {
+                        root.notification = ""
+                        authenticator.tryUnlock(password)
                     }
-                ]
 
-                Loader {
-                    Layout.fillWidth: true
-                    Layout.preferredHeight: item ? item.implicitHeight : 0
-                    active: true // TODO configurable
-                    source: "MediaControls.qml"
+                    actionItems: [
+                        ActionButton {
+                            text: i18nd("plasma_lookandfeel_org.kde.lookandfeel", "Switch User")
+                            iconSource: "system-switch-user"
+                            onClicked: mainStack.push(switchSessionPage)
+                            // the current session isn't listed in the model, hence a check for greater than zero, not one
+                            visible: (sessionsModel.count > 0 || sessionsModel.canStartNewSession) && sessionsModel.canSwitchUser
+                        }
+                    ]
+
+                    Loader {
+                        Layout.fillWidth: true
+                        Layout.preferredHeight: item ? item.implicitHeight : 0
+                        active: true // TODO configurable
+                        source: "MediaControls.qml"
+                    }
                 }
             }
+            Loader {
+                id: inputPanel
+                property bool keyboardActive: item ? item.active : false
+                Layout.fillWidth: true
+                Layout.preferredHeight: item ? (item.active ? item.implicitHeight : 0) : 0
+                function showHide() {
+                    if (Qt.inputMethod.visible) {
+                        Qt.inputMethod.hide();
+                    } else {
+                        item.activated = true;
+                        Qt.inputMethod.show();
+                    }
+                }
+                Component.onCompleted: inputPanel.source = "VirtualKeyboard.qml"
+            }
         }
 
         Component {
@@ -250,6 +269,12 @@ PlasmaCore.ColorScope {
                 margins: units.smallSpacing
             }
 
+            PlasmaComponents.ToolButton {
+                text: i18ndc("plasma_lookandfeel_org.kde.lookandfeel", "Button to show/hide virtual keyboard", "Virtual Keyboard")
+                iconName: inputPanel.keyboardActive ? "input-keyboard-virtual-on" : "input-keyboard-virtual-off"
+                onClicked: inputPanel.showHide()
+            }
+
             KeyboardLayoutButton {
             }
 

lookandfeel/contents/lockscreen/VirtualKeyboard.qml

@@ -0,0 +1,28 @@
+/********************************************************************
+ This file is part of the KDE project.
+
+Copyright (C) 2017 Martin Gräßlin <mgraesslin@kde.org>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+import QtQuick 2.5
+import QtQuick.VirtualKeyboard 2.1
+
+InputPanel {
+    id: inputPanel
+    property bool activated: false
+    active: activated && Qt.inputMethod.visible
+    visible: active
+    width: parent.width
+}