mobile/dive-list: make sure filter input area is visible

Since apparently the header property of the ListView isn't reliably
making sure that our filter input line is visible, let's move the filter
header to be it's own visual element and manually manage the
relationship between that and the ListView.

The obvious idea was to anchor the ListView to the bottom of the
filterHeader, but that didn't work in my tests. So instead we are using
the topMargin to make sure that there is space to show the header.

Because this re-indents the whole filterHeader, 'git show -w' gives a
much better idea what this commit actually changes.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

mobile-widgets/qml/DiveList.qml

@@ -353,21 +353,21 @@ Kirigami.ScrollablePage {
 		visible: diveListView.visible && diveListView.count === 0
 	}
 
-	Component {
-		id: filterHeader
 	Rectangle {
-			id: filterRectangle
+		id: filterHeader
 		visible: filterBar.height > 0
 		implicitHeight: filterBar.implicitHeight
 		implicitWidth: filterBar.implicitWidth
 		height: filterBar.height
-			anchors.left: parent.left
+		anchors {
-			anchors.right: parent.right
+			top: parent.top
+			left: parent.left
+			right: parent.right
+		}
 		color: subsurfaceTheme.backgroundColor
 		enabled: rootItem.filterToggle
 		RowLayout {
 			id: filterBar
-				z: 5 //make sure it sits on top
 			states: [
 				State {
 					name: "isVisible"
@@ -379,7 +379,6 @@ Kirigami.ScrollablePage {
 					when: !rootItem.filterToggle
 					PropertyChanges { target: filterBar; height: 0 }
 				}
-
 			]
 			transitions: [
 				Transition { NumberAnimation { property: "height"; duration: 400; easing.type: Easing.InOutQuad }}
@@ -389,6 +388,7 @@ Kirigami.ScrollablePage {
 			anchors.leftMargin: Kirigami.Units.gridUnit / 2
 			anchors.rightMargin: Kirigami.Units.gridUnit / 2
 			TemplateComboBox {
+				visible: filterBar.height === sitefilter.implicitHeight
 				id: sitefilterMode
 				editable: false
 				model: ListModel {
@@ -405,7 +405,6 @@ Kirigami.ScrollablePage {
 			}
 			Controls.TextField  {
 				id: sitefilter
-					z: 10
 				verticalAlignment: TextInput.AlignVCenter
 				Layout.fillWidth: true
 				text: ""
@@ -423,22 +422,18 @@ Kirigami.ScrollablePage {
 			}
 			Controls.Label {
 				id: numShown
-					z: 10
 				verticalAlignment: Text.AlignVCenter
 				text: diveModel.shown
 			}
 		}
 	}
-	}
-
 	ListView {
 		id: diveListView
+		topMargin: filterHeader.height
 		anchors.fill: parent
 		model: diveListModel
 		currentIndex: -1
 		delegate: diveOrTripDelegate
-		header: filterHeader
-		headerPositioning: ListView.OverlayHeader
 		boundsBehavior: Flickable.DragOverBounds
 		maximumFlickVelocity: parent.height * 5
 		bottomMargin: Kirigami.Units.iconSizes.medium + Kirigami.Units.gridUnit