Porting QML Plasmoids to Plasma 2

The Plasma Quick APIs have been ported to QtQuick2. This has been done with API compatibility in mind. Usually, it is pretty easy to get your QtQuick2 code running on top of QtQuick2 and Plasma2. This document guides you through the important changes in QtQuick2.

The following modules have been fully ported:

org.kde.plasma.core (PlasmaCore)
org.kde.plasma.components (PlasmaComponents)
org.kde.plasma.extras (PlasmaExtras)
org.kde.qtextracomponents (QtExtras)
org.kde.draganddrop
org.kde.runnermanager (work in progress)

API Changes

The API has been kept compatible to minimize the porting effort to Plasma2. With the following changes, you can get your code running on Plasma2:

Change import version numbers of all above components to 2.0
org.kde.locale is gone, use Qt.locale() or PlasmaCore.Format for localization.
PlasmaCore.Dialog: activateWindow() is gone, use requestActivate() (from QWindow)
PlasmaCore.Dialog.activeWindow is gone, use Dialog.active (inherited from QWindow)
PlasmaCore.Dialog.windowFlags is gone, use Dialog.flags (inherited from QWindow)
PlasmaCore.Theme: mSize now takes a font as argument, theme.mSize(theme.defaultFont)
PlasmaCore.ToolTip: image property now takes a QString, which is passed as source into an Image item
QIcon has gone from the API as creatable type, replace QIcon("icon-name") with "icon-name" (PlasmaCore.IconItem.iconSource also understands QIcon)
theme.defaultFont.mSize changes to theme.mSize(theme.defaultFont), likewise for other fonts.
you cannot import *.private imports from other components anymore, this is a new security restriction
theme.smallIconSize becomes units.iconSizes.small
theme.smallMediumIconSize becomes units.iconSizes.smallMedium
theme.mediumIconSize becomes units.iconSizes.medium
theme.largeIconSize becomes units.iconSizes.large
theme.hugeIconSize becomes units.iconSizes.huge
theme.enormousIconSize becomes units.iconSizes.enormous

Backwards compatible API Improvements:

org.kde.dirmodel has been added, allowing efficient access to the filesystem
icon sizes now scale with the screen's DPI
units.* in PlasmaCore provides the tools for DPI-scalabel UIs (gridUnit, smallSpacing, largeSpacing, devicePixelRatio)
PlasmaCore.ToolTip can now optionally include Components
PlasmaCore.MenuItem.icon now accepts icons as QString, as well as QIcon

Please note that the Plasma QtQuick 2 APIs are still subject to change. This document is work in progress.

Versioning of plugins

All plugin versions have been upped to 2.0. PlasmaComponents, PlasmaCore, PlasmaExtras, QtExtras, DragAndDrop, RunnerModel, etc. are now at version two. Locale was at 1.0, and is now also at 2.0. Change lines like:

import org.kde.plasma.components 0.1 as PlasmaComponents

to

import org.kde.plasma.components 2.0 as PlasmaComponents

Namespacing of enums

As we cannot export new types into the global namespace, enums have to be loaded into a namespace. In order to do this, make sure

you are importing the plugin in question using a namespace (import org.kde.foo 2.0 as MyFoo)
you change references to enums defined in a class with its full name, i.e. PlasmaCore.Dialog.Closed (not Dialog.Closed)

Configuration

Plasma2 doesn't use .ui files anymore. Instead, config pages has to be written in QML. In order to populate the configuration dialog, put a config.qml file in the config/ directory of the plasmoid.

config/config.qml

The config.qml file must be an instance of the ConfigModel {} component, which can only contains ConfigCategory {} items.

 import org.kde.plasma.configuration 0.1
 ConfigModel {
     ConfigCategory {
          name: "General"
          icon: "plasma"
          source: "configGeneral.qml"
     }
     ConfigCategory {
          name: "Page2"
          icon: "config"
          source: "whatever.qml"
     }
     ...
}

The source properties define qml file names that represent the pages of the config categories and will be searched for in the ui/ directory of the Plasma package.

Mapping from config pages to plasmoid configuration

TODO

config/main.xml

As in Plasma1, the schema for the configuration stays in a KConfigXT main.xml file under the confg directory, that will define what the allowed config keys are.

<?xml version="1.0" encoding="UTF-8"?>
<kcfg xmlns="http://www.kde.org/standards/kcfg/1.0"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0
      http://www.kde.org/standards/kcfg/1.0/kcfg.xsd" >
  <kcfgfile name=""/>
  <group name="General">
    <entry name="Test" type="String">
      <label>This is a test</label>
      <default>test</default>
    </entry>
  </group>
</kcfg>

Reading and writing the configuration from the plasmoid code

The plasmoid global object available in the implementation of the QML plasmoid has a new property available: plasmoid.configuration.

the configuration object is an Object that has a property for each configuration key in the config file, with the same name. It is possible to use property bindings for those properties (so the plasmoid implementation doesn't have to worry about applying configuration values after the user configured something with the config dialog). If a JavaScript piece assigns a value to one of the properties of configuration, the new value will be written on the configuration on disk.