An item in a treeview. More...
Inherited by KeyMappingEditorComponent.
Public Member Functions | |
| TreeViewItem () | |
| Constructor. | |
| virtual | ~TreeViewItem () |
| Destructor. | |
| int | getNumSubItems () const throw () |
| Returns the number of sub-items that have been added to this item. | |
| TreeViewItem * | getSubItem (int index) const throw () |
| Returns one of the item's sub-items. | |
| void | clearSubItems () |
| Removes any sub-items. | |
| void | addSubItem (TreeViewItem *newItem, int insertPosition=-1) |
| Adds a sub-item. | |
| void | removeSubItem (int index, bool deleteItem=true) |
| Removes one of the sub-items. | |
| TreeView * | getOwnerView () const throw () |
| Returns the TreeView to which this item belongs. | |
| TreeViewItem * | getParentItem () const throw () |
| Returns the item within which this item is contained. | |
| bool | isOpen () const throw () |
| True if this item is currently open in the treeview. | |
| void | setOpen (bool shouldBeOpen) |
| Opens or closes the item. | |
| bool | isSelected () const throw () |
| True if this item is currently selected. | |
| void | setSelected (bool shouldBeSelected, bool deselectOtherItemsFirst) |
| Selects or deselects the item. | |
| const Rectangle< int > | getItemPosition (bool relativeToTreeViewTopLeft) const throw () |
| Returns the rectangle that this item occupies. | |
| void | treeHasChanged () const throw () |
| Sends a signal to the treeview to make it refresh itself. | |
| void | repaintItem () const |
| Sends a repaint message to redraw just this item. | |
| int | getRowNumberInTree () const throw () |
| Returns the row number of this item in the tree. | |
| bool | areAllParentsOpen () const throw () |
| Returns true if all the item's parent nodes are open. | |
| void | setLinesDrawnForSubItems (bool shouldDrawLines) throw () |
| Changes whether lines are drawn to connect any sub-items to this item. | |
| virtual bool | mightContainSubItems ()=0 |
| Tells the tree whether this item can potentially be opened. | |
| virtual const String | getUniqueName () const |
| Returns a string to uniquely identify this item. | |
| virtual void | itemOpennessChanged (bool isNowOpen) |
| Called when an item is opened or closed. | |
| virtual int | getItemWidth () const |
| Must return the width required by this item. | |
| virtual int | getItemHeight () const |
| Must return the height required by this item. | |
| virtual bool | canBeSelected () const |
| You can override this method to return false if you don't want to allow the user to select this item. | |
| virtual Component * | createItemComponent () |
| Creates a component that will be used to represent this item. | |
| virtual void | paintItem (Graphics &g, int width, int height) |
| Draws the item's contents. | |
| virtual void | paintOpenCloseButton (Graphics &g, int width, int height, bool isMouseOver) |
| Draws the item's open/close button. | |
| virtual void | itemClicked (const MouseEvent &e) |
| Called when the user clicks on this item. | |
| virtual void | itemDoubleClicked (const MouseEvent &e) |
| Called when the user double-clicks on this item. | |
| virtual void | itemSelectionChanged (bool isNowSelected) |
| Called when the item is selected or deselected. | |
| virtual const String | getTooltip () |
| The item can return a tool tip string here if it wants to. | |
| virtual const String | getDragSourceDescription () |
| To allow items from your treeview to be dragged-and-dropped, implement this method. | |
| virtual bool | isInterestedInFileDrag (const StringArray &files) |
| If you want your item to be able to have files drag-and-dropped onto it, implement this method and return true. | |
| virtual void | filesDropped (const StringArray &files, int insertIndex) |
| When files are dropped into this item, this callback is invoked. | |
| virtual bool | isInterestedInDragSource (const String &sourceDescription, Component *sourceComponent) |
| If you want your item to act as a DragAndDropTarget, implement this method and return true. | |
| virtual void | itemDropped (const String &sourceDescription, Component *sourceComponent, int insertIndex) |
| When a things are dropped into this item, this callback is invoked. | |
| void | setDrawsInLeftMargin (bool canDrawInLeftMargin) throw () |
| Sets a flag to indicate that the item wants to be allowed to draw all the way across to the left edge of the treeview. | |
| XmlElement * | getOpennessState () const throw () |
| Saves the current state of open/closed nodes so it can be restored later. | |
| void | restoreOpennessState (const XmlElement &xml) throw () |
| Restores the openness of this item and all its sub-items from a saved state. | |
| int | getIndexInParent () const throw () |
| Returns the index of this item in its parent's sub-items. | |
| bool | isLastOfSiblings () const throw () |
| Returns true if this item is the last of its parent's sub-itens. | |
| const String | getItemIdentifierString () const |
| Creates a string that can be used to uniquely retrieve this item in the tree. | |
An item in a treeview.
A TreeViewItem can either be a leaf-node in the tree, or it can contain its own sub-items.
To implement an item that contains sub-items, override the itemOpennessChanged() method so that when it is opened, it adds the new sub-items to itself using the addSubItem method. Depending on the nature of the item it might choose to only do this the first time it's opened, or it might want to refresh itself each time. It also has the option of deleting its sub-items when it is closed, or leaving them in place.
| TreeViewItem::TreeViewItem | ( | ) |
Constructor.
| virtual TreeViewItem::~TreeViewItem | ( | ) | [virtual] |
Destructor.
| int TreeViewItem::getNumSubItems | ( | ) | const throw () |
Returns the number of sub-items that have been added to this item.
Note that this doesn't mean much if the node isn't open.
| TreeViewItem* TreeViewItem::getSubItem | ( | int | index | ) | const throw () |
Returns one of the item's sub-items.
Remember that the object returned might get deleted at any time when its parent item is closed or refreshed, depending on the nature of the items you're using.
| void TreeViewItem::clearSubItems | ( | ) |
Removes any sub-items.
| void TreeViewItem::addSubItem | ( | TreeViewItem * | newItem, | |
| int | insertPosition = -1 | |||
| ) |
Adds a sub-item.
| newItem | the object to add to the item's sub-item list. Once added, these can be found using getSubItem(). When the items are later removed with removeSubItem() (or when this item is deleted), they will be deleted. | |
| insertPosition | the index which the new item should have when it's added. If this value is less than 0, the item will be added to the end of the list. |
| void TreeViewItem::removeSubItem | ( | int | index, | |
| bool | deleteItem = true | |||
| ) |
Removes one of the sub-items.
| index | the item to remove | |
| deleteItem | if true, the item that is removed will also be deleted. |
| TreeView* TreeViewItem::getOwnerView | ( | ) | const throw () |
Returns the TreeView to which this item belongs.
| TreeViewItem* TreeViewItem::getParentItem | ( | ) | const throw () |
Returns the item within which this item is contained.
| bool TreeViewItem::isOpen | ( | ) | const throw () |
True if this item is currently open in the treeview.
| void TreeViewItem::setOpen | ( | bool | shouldBeOpen | ) |
Opens or closes the item.
When opened or closed, the item's itemOpennessChanged() method will be called, and a subclass should use this callback to create and add any sub-items that it needs to.
| bool TreeViewItem::isSelected | ( | ) | const throw () |
True if this item is currently selected.
Use this when painting the node, to decide whether to draw it as selected or not.
| void TreeViewItem::setSelected | ( | bool | shouldBeSelected, | |
| bool | deselectOtherItemsFirst | |||
| ) |
Selects or deselects the item.
This will cause a callback to itemSelectionChanged()
| const Rectangle<int> TreeViewItem::getItemPosition | ( | bool | relativeToTreeViewTopLeft | ) | const throw () |
Returns the rectangle that this item occupies.
If relativeToTreeViewTopLeft is true, the co-ordinates are relative to the top-left of the TreeView comp, so this will depend on the scroll-position of the tree. If false, it is relative to the top-left of the topmost item in the tree (so this would be unaffected by scrolling the view).
| void TreeViewItem::treeHasChanged | ( | ) | const throw () |
Sends a signal to the treeview to make it refresh itself.
Call this if your items have changed and you want the tree to update to reflect this.
| void TreeViewItem::repaintItem | ( | ) | const |
Sends a repaint message to redraw just this item.
Note that you should only call this if you want to repaint a superficial change. If you're altering the tree's nodes, you should instead call treeHasChanged().
| int TreeViewItem::getRowNumberInTree | ( | ) | const throw () |
Returns the row number of this item in the tree.
The row number of an item will change according to which items are open.
| bool TreeViewItem::areAllParentsOpen | ( | ) | const throw () |
Returns true if all the item's parent nodes are open.
This is useful to check whether the item might actually be visible or not.
| void TreeViewItem::setLinesDrawnForSubItems | ( | bool | shouldDrawLines | ) | throw () |
Changes whether lines are drawn to connect any sub-items to this item.
By default, line-drawing is turned on.
| virtual bool TreeViewItem::mightContainSubItems | ( | ) | [pure virtual] |
Tells the tree whether this item can potentially be opened.
If your item could contain sub-items, this should return true; if it returns false then the tree will not try to open the item. This determines whether or not the item will be drawn with a 'plus' button next to it.
Implemented in KeyMappingEditorComponent.
| virtual const String TreeViewItem::getUniqueName | ( | ) | const [virtual] |
Returns a string to uniquely identify this item.
If you're planning on using the TreeView::getOpennessState() method, then these strings will be used to identify which nodes are open. The string should be unique amongst the item's sibling items, but it's ok for there to be duplicates at other levels of the tree.
If you're not going to store the state, then it's ok not to bother implementing this method.
Reimplemented in KeyMappingEditorComponent.
| virtual void TreeViewItem::itemOpennessChanged | ( | bool | isNowOpen | ) | [virtual] |
Called when an item is opened or closed.
When setOpen() is called and the item has specified that it might have sub-items with the mightContainSubItems() method, this method is called to let the item create or manage its sub-items.
So when this is called with isNowOpen set to true (i.e. when the item is being opened), a subclass might choose to use clearSubItems() and addSubItem() to refresh its sub-item list.
When this is called with isNowOpen set to false, the subclass might want to use clearSubItems() to save on space, or it might choose to leave them, depending on the nature of the tree.
You could also use this callback as a trigger to start a background process which asynchronously creates sub-items and adds them, if that's more appropriate for the task in hand.
| virtual int TreeViewItem::getItemWidth | ( | ) | const [virtual] |
Must return the width required by this item.
If your item needs to have a particular width in pixels, return that value; if you'd rather have it just fill whatever space is available in the treeview, return -1.
If all your items return -1, no horizontal scrollbar will be shown, but if any items have fixed widths and extend beyond the width of the treeview, a scrollbar will appear.
Each item can be a different width, but if they change width, you should call treeHasChanged() to update the tree.
| virtual int TreeViewItem::getItemHeight | ( | ) | const [virtual] |
Must return the height required by this item.
This is the height in pixels that the item will take up. Items in the tree can be different heights, but if they change height, you should call treeHasChanged() to update the tree.
| virtual bool TreeViewItem::canBeSelected | ( | ) | const [virtual] |
You can override this method to return false if you don't want to allow the user to select this item.
| virtual Component* TreeViewItem::createItemComponent | ( | ) | [virtual] |
Creates a component that will be used to represent this item.
You don't have to implement this method - if it returns 0 then no component will be used for the item, and you can just draw it using the paintItem() callback. But if you do return a component, it will be positioned in the treeview so that it can be used to represent this item.
The component returned will be managed by the treeview, so always return a new component, and don't keep a reference to it, as the treeview will delete it later when it goes off the screen or is no longer needed. Also bear in mind that if the component keeps a reference to the item that created it, that item could be deleted before the component. Its position and size will be completely managed by the tree, so don't attempt to move it around.
Something you may want to do with your component is to give it a pointer to the TreeView that created it. This is perfectly safe, and there's no danger of it becoming a dangling pointer because the TreeView will always delete the component before it is itself deleted.
As long as you stick to these rules you can return whatever kind of component you like. It's most useful if you're doing things like drag-and-drop of items, or want to use a Label component to edit item names, etc.
| virtual void TreeViewItem::paintItem | ( | Graphics & | g, | |
| int | width, | |||
| int | height | |||
| ) | [virtual] |
Draws the item's contents.
You can choose to either implement this method and draw each item, or you can use createItemComponent() to create a component that will represent the item.
If all you need in your tree is to be able to draw the items and detect when the user selects or double-clicks one of them, it's probably enough to use paintItem(), itemClicked() and itemDoubleClicked(). If you need more complicated interactions, you may need to use createItemComponent() instead.
| g | the graphics context to draw into | |
| width | the width of the area available for drawing | |
| height | the height of the area available for drawing |
| virtual void TreeViewItem::paintOpenCloseButton | ( | Graphics & | g, | |
| int | width, | |||
| int | height, | |||
| bool | isMouseOver | |||
| ) | [virtual] |
Draws the item's open/close button.
If you don't implement this method, the default behaviour is to call LookAndFeel::drawTreeviewPlusMinusBox(), but you can override it for custom effects.
| virtual void TreeViewItem::itemClicked | ( | const MouseEvent & | e | ) | [virtual] |
Called when the user clicks on this item.
If you're using createItemComponent() to create a custom component for the item, the mouse-clicks might not make it through to the treeview, but this is how you find out about clicks when just drawing each item individually.
The associated mouse-event details are passed in, so you can find out about which button, where it was, etc.
| virtual void TreeViewItem::itemDoubleClicked | ( | const MouseEvent & | e | ) | [virtual] |
Called when the user double-clicks on this item.
If you're using createItemComponent() to create a custom component for the item, the mouse-clicks might not make it through to the treeview, but this is how you find out about clicks when just drawing each item individually.
The associated mouse-event details are passed in, so you can find out about which button, where it was, etc.
If not overridden, the base class method here will open or close the item as if the 'plus' button had been clicked.
| virtual void TreeViewItem::itemSelectionChanged | ( | bool | isNowSelected | ) | [virtual] |
Called when the item is selected or deselected.
Use this if you want to do something special when the item's selectedness changes. By default it'll get repainted when this happens.
| virtual const String TreeViewItem::getTooltip | ( | ) | [virtual] |
The item can return a tool tip string here if it wants to.
| virtual const String TreeViewItem::getDragSourceDescription | ( | ) | [virtual] |
To allow items from your treeview to be dragged-and-dropped, implement this method.
If this returns a non-empty name then when the user drags an item, the treeview will try to find a DragAndDropContainer in its parent hierarchy, and will use it to trigger a drag-and-drop operation, using this string as the source description, with the treeview itself as the source component.
If you need more complex drag-and-drop behaviour, you can use custom components for the items, and use those to trigger the drag.
To accept drag-and-drop in your tree, see isInterestedInDragSource(), isInterestedInFileDrag(), etc.
| virtual bool TreeViewItem::isInterestedInFileDrag | ( | const StringArray & | files | ) | [virtual] |
If you want your item to be able to have files drag-and-dropped onto it, implement this method and return true.
If you return true and allow some files to be dropped, you'll also need to implement the filesDropped() method to do something with them.
Note that this will be called often, so make your implementation very quick! There's certainly no time to try opening the files and having a think about what's inside them!
For responding to internal drag-and-drop of other types of object, see isInterestedInDragSource().
| virtual void TreeViewItem::filesDropped | ( | const StringArray & | files, | |
| int | insertIndex | |||
| ) | [virtual] |
When files are dropped into this item, this callback is invoked.
For this to work, you'll need to have also implemented isInterestedInFileDrag(). The insertIndex value indicates where in the list of sub-items the files were dropped.
| virtual bool TreeViewItem::isInterestedInDragSource | ( | const String & | sourceDescription, | |
| Component * | sourceComponent | |||
| ) | [virtual] |
If you want your item to act as a DragAndDropTarget, implement this method and return true.
If you implement this method, you'll also need to implement itemDropped() in order to handle the items when they are dropped. To respond to drag-and-drop of files from external applications, see isInterestedInFileDrag().
| virtual void TreeViewItem::itemDropped | ( | const String & | sourceDescription, | |
| Component * | sourceComponent, | |||
| int | insertIndex | |||
| ) | [virtual] |
When a things are dropped into this item, this callback is invoked.
For this to work, you need to have also implemented isInterestedInDragSource(). The insertIndex value indicates where in the list of sub-items the new items should be placed.
| void TreeViewItem::setDrawsInLeftMargin | ( | bool | canDrawInLeftMargin | ) | throw () |
Sets a flag to indicate that the item wants to be allowed to draw all the way across to the left edge of the treeview.
By default this is false, which means that when the paintItem() method is called, its graphics context is clipped to only allow drawing within the item's rectangle. If this flag is set to true, then the graphics context isn't clipped on its left side, so it can draw all the way across to the left margin. Note that the context will still have its origin in the same place though, so the coordinates of anything to its left will be negative. It's mostly useful if you want to draw a wider bar behind the highlighted item.
| XmlElement* TreeViewItem::getOpennessState | ( | ) | const throw () |
Saves the current state of open/closed nodes so it can be restored later.
This takes a snapshot of which sub-nodes have been explicitly opened or closed, and records it as XML. To identify node objects it uses the TreeViewItem::getUniqueName() method to create named paths. This means that the same state of open/closed nodes can be restored to a completely different instance of the tree, as long as it contains nodes whose unique names are the same.
You'd normally want to use TreeView::getOpennessState() rather than call it for a specific item, but this can be handy if you need to briefly save the state for a section of the tree.
The caller is responsible for deleting the object that is returned.
| void TreeViewItem::restoreOpennessState | ( | const XmlElement & | xml | ) | throw () |
Restores the openness of this item and all its sub-items from a saved state.
See TreeView::restoreOpennessState for more details.
You'd normally want to use TreeView::restoreOpennessState() rather than call it for a specific item, but this can be handy if you need to briefly save the state for a section of the tree.
| int TreeViewItem::getIndexInParent | ( | ) | const throw () |
Returns the index of this item in its parent's sub-items.
| bool TreeViewItem::isLastOfSiblings | ( | ) | const throw () |
Returns true if this item is the last of its parent's sub-itens.
| const String TreeViewItem::getItemIdentifierString | ( | ) | const |
Creates a string that can be used to uniquely retrieve this item in the tree.
The string that is returned can be passed to TreeView::findItemFromIdentifierString(). The string takes the form of a path, constructed from the getUniqueName() of this item and all its parents, so these must all be correctly implemented for it to work.
1.6.3
