[System Monitor Applet] Add setting for update interval

BUG: 353063
FIXED-IN: 5.13.0

Differential Revision: https://phabricator.kde.org/D6864

applets/systemmonitor/common/contents/config/main.xml

@@ -9,6 +9,10 @@
     <entry name="sources" type="StringList">
         <label>Which "systemmonitor" dataengine sources this applet will take data from.</label>
     </entry>
+    <entry name="updateInterval" type="Int">
+        <label>The interval in milliseconds to update the data shown.</label>
+        <default>2000</default>
+    </entry>
   </group>
 
 </kcfg>

applets/systemmonitor/common/contents/ui/Applet.qml

@@ -81,7 +81,7 @@ Item {
         id: smSource
 
         engine: "systemmonitor"
-        interval: 2000
+        interval: plasmoid.configuration.updateInterval
         onSourceAdded: {
             if (plasmoid.configuration.sources.length > 0 &&
                 plasmoid.configuration.sources.indexOf(encodeURIComponent(source)) === -1) {

applets/systemmonitor/common/contents/ui/ConfigGeneral.qml

@@ -48,6 +48,7 @@ Item {
             }
         }
     }
+    property int cfg_updateInterval
 
     signal sourceAdded(string source)
 
@@ -102,6 +103,22 @@ Item {
         id: mainColumn
         anchors.left: parent.left
 
+        Layouts.RowLayout {
+            Controls.Label {
+                text: i18n("Update Interval:")
+            }
+
+            Controls.SpinBox {
+                id: updateIntervalSpinBox
+                decimals: 2
+                suffix: i18nc("Suffix for spinbox (seconds)", " sec")
+                maximumValue: 1000
+                stepSize: 0.5
+                onValueChanged: cfg_updateInterval = value * 1000
+                Component.onCompleted: value = cfg_updateInterval / 1000
+            }
+        }
+
         Repeater {
             id: repeater
             model: sourcesModel