Don't show the pre-flight check list option if the custom plugin doesn't provide one.

src/QmlControls/PreFlightCheckList.qml

-/****************************************************************************
- *
- *   (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
- *
- * QGroundControl is licensed according to the terms in the file
- * COPYING.md in the root of the source code directory.
- *
- ****************************************************************************/
-
-import QtQuick          2.3
-import QtQuick.Controls 1.2
-import QtQml.Models     2.1
-
-import QGroundControl               1.0
-import QGroundControl.ScreenTools   1.0
-import QGroundControl.Controls      1.0
-
-Rectangle {
-    width:      mainColumn.width  + ScreenTools.defaultFontPixelWidth * 3
-    height:     mainColumn.height + ScreenTools.defaultFontPixelHeight
-    color:      qgcPal.windowShade
-    radius:     3
-
-    property alias model: checkListRepeater.model
-
-    property bool _passed:  false
-
-    function _handleGroupPassedChanged(index, passed) {
-        if (passed) {
-            // Collapse current group
-            var group = checkListRepeater.itemAt(index)
-            group._checked = false
-            // Expand next group
-            if (index + 1 < checkListRepeater.count) {
-                group = checkListRepeater.itemAt(index + 1)
-                group.enabled = true
-                group._checked = true
-            }
-        }
-        _passed = passed
-    }
-
-    // We delay the updates when a group passes so the user can see all items green for a moment prior to hiding
-    Timer {
-        id:         delayedGroupPassed
-        interval:   750
-
-        property int index
-
-        onTriggered: _handleGroupPassedChanged(index, true /* passed */)
-    }
-
-    Column {
-        id:                     mainColumn
-        width:                  40  * ScreenTools.defaultFontPixelWidth
-        spacing:                0.8 * ScreenTools.defaultFontPixelWidth
-        anchors.left:           parent.left
-        anchors.top:            parent.top
-        anchors.topMargin:      0.6 * ScreenTools.defaultFontPixelWidth
-        anchors.leftMargin:     1.5 * ScreenTools.defaultFontPixelWidth
-
-        function groupPassedChanged(index, passed) {
-            if (passed) {
-                delayedGroupPassed.index = index
-                delayedGroupPassed.restart()
-            } else {
-                _handleGroupPassedChanged(index, passed)
-            }
-        }
-
-        // Header/title of checklist
-        Item {
-            width:      parent.width
-            height:     1.75 * ScreenTools.defaultFontPixelHeight
-
-            QGCLabel {
-                text:                   qsTr("Pre-Flight Checklist %1").arg(_passed ? qsTr("(passed)") : "")
-                anchors.left:           parent.left
-                anchors.verticalCenter: parent.verticalCenter
-                font.pointSize:         ScreenTools.mediumFontPointSize
-            }
-            QGCButton {
-                width:                  1.2 * ScreenTools.defaultFontPixelHeight
-                height:                 1.2 * ScreenTools.defaultFontPixelHeight
-                anchors.right:          parent.right
-                anchors.verticalCenter: parent.verticalCenter
-                tooltip:                qsTr("Reset the checklist (e.g. after a vehicle reboot)")
-
-                onClicked:              model.reset()
-
-                QGCColoredImage {
-                    source:         "/qmlimages/MapSyncBlack.svg"
-                    color:          qgcPal.buttonText
-                    anchors.fill:   parent
-                }
-            }
-        }
-
-        // All check list items
-        Repeater {
-            id: checkListRepeater
-        }
-    }
-}

src/ui/preferences/GeneralSettings.qml

@@ -431,7 +431,7 @@ Rectangle {
                             FactCheckBox {
                                 text:       qsTr("Use Preflight Checklist")
                                 fact:       _useChecklist
-                                visible:    _useChecklist.visible
+                                visible:    _useChecklist.visible && QGroundControl.corePlugin.options.preFlightChecklistUrl.toString().length
 
                                 property Fact _useChecklist: QGroundControl.settingsManager.appSettings.useChecklist
                             }