TableView: Expand to single column and prevent multiple use

This fix ensures that we can only add a TableViewColumn exactly
once. It also automatically expands the column with to the viewport
when only one column is in use.

In addition I have disabled dragging when columnCount == 1
as it was pointless.

Change-Id: Ief6011c3e58166907836bf55b0fa6643698192d2
Reviewed-by: Caroline Chao <caroline.chao@digia.com>

src/controls/TableView.qml

@@ -303,7 +303,12 @@ ScrollView {
         if (typeof column['createObject'] === 'function')
             object = column.createObject(root)
 
+        else if (object.__view) {
+            console.warn("TableView::insertColumn(): you cannot add a column to multiple views")
+            return null
+        }
         if (index >= 0 && index <= columnCount && object.Accessible.role === Accessible.ColumnHeader) {
+            object.__view = root
             columnModel.insert(index, {columnItem: object})
             return object
         }
@@ -616,7 +621,7 @@ ScrollView {
 
                     delegate: Item {
                         z:-index
-                        width: modelData.width
+                        width: columnCount == 1 ? viewport.width + __verticalScrollBar.width : modelData.width
                         visible: modelData.visible
                         height: headerVisible ? headerStyle.height : 0
 
@@ -655,7 +660,7 @@ ScrollView {
                             // NOTE: the direction is different from the master branch
                             // so this indicates that I am using an invalid assumption on item ordering
                             onPositionChanged: {
-                                if (pressed) { // only do this while dragging
+                                if (pressed && columnCount > 1) { // only do this while dragging
                                     for (var h = columnCount-1 ; h >= 0 ; --h) {
                                         if (drag.target.x > headerrow.children[h].x) {
                                             repeater.targetIndex = h
@@ -680,7 +685,7 @@ ScrollView {
                             }
                             drag.maximumX: 1000
                             drag.minimumX: -1000
-                            drag.target: draghandle
+                            drag.target: columnCount > 1 ? draghandle : null
                         }
 
                         Loader {
@@ -708,6 +713,7 @@ ScrollView {
                             anchors.rightMargin: -width/2
                             width: 16 ; height: parent.height
                             anchors.right: parent.right
+                            enabled: columnCount > 1
                             onPositionChanged:  {
                                 var newHeaderWidth = modelData.width + (mouseX - offset)
                                 modelData.width = Math.max(minimumSize, newHeaderWidth)
@@ -728,7 +734,7 @@ ScrollView {
                                     modelData.width = minWidth
                             }
                             onPressedChanged: if (pressed) offset=mouseX
-                            cursorShape: Qt.SplitHCursor
+                            cursorShape: enabled ? Qt.SplitHCursor : Qt.ArrowCursor
                         }
                     }
                 }

src/controls/TableViewColumn.qml

@@ -49,6 +49,10 @@ import QtQuick 2.1
 */
 
 QtObject {
+
+    /*! \internal */
+    property Item __view: null
+
     /*! The title text of the column. */
     property string title
 
@@ -56,8 +60,10 @@ QtObject {
     property string role
 
     /*! The current width of the column
-    The default value depends on platform. */
-    property int width: 160
+    The default value depends on platform. If only one
+    column is defined, the width expands to the viewport.
+    */
+    property int width: (__view && __view.columnCount === 1) ? __view.viewport.width : 160
 
     /*! The visible status of the column. */
     property bool visible: true

tests/auto/controls/data/tst_tableview.qml

@@ -240,6 +240,23 @@ TestCase {
         table.destroy()
     }
 
+    function test_columnWidth() {
+        var tableView = Qt.createQmlObject('import QtQuick 2.1; import QtQuick.Controls 1.0; TableView { }', testCase, '');
+        compare(tableView.columnCount, 0)
+        var column = newColumn.createObject(testCase, {title: "title 1"});
+        verify(column.__view === null)
+        compare(column.width, 160)
+        compare(column.title, "title 1")
+        tableView.addColumn(column)
+        compare(column.__view, tableView)
+        compare(column.width, tableView.viewport.width)
+        var tableView2 = Qt.createQmlObject('import QtQuick 2.1; import QtQuick.Controls 1.0; TableView { }', testCase, '');
+        tableView2.addColumn(column) // should not work
+        compare(column.__view, tableView) //same as before
+        tableView2.destroy()
+        tableView.destroy()
+    }
+
     function test_dynamicColumns() {
         var component = Qt.createComponent("tableview/table_dynamiccolumns.qml")
         compare(component.status, Component.Ready)