Special Functions of the Tree Structure

Use

The tree structure is comprised of the following areas:

The Structure

The structure is defined by the initial table that you specify with the FACTORY method. It is displayed by the column header , which is the top row of the tree structure. Every node in a tree structure has exactly the structure that is defined in the initial table.
Hierarchy Column

The first column of the tree structure is always the hierarchy column . It is not part of the initial table. It contains symbols that the user can use to display or hide lower levels of a node. Using different icons, you are able to display whether a node is a branch with subnodes or a leaf.

By default the hierarchy column has no text. However, for each node, you are able to determine which text is to appear in the hierarchy column.
Node

The actual entries in the tree structure are called nodes . Every node has the same structure as the initial table. Every node is uniquely identified by a key.

A node can either be a leaf or a branch: Branches contain either more branches or leaves that are not subdivided any further as subnodes.
Item

Items are components of a node: Each node contains exactly as many items as are contained in the initial table. In this way you are able to compare items with the entries in a column.

Based on the deviating data model, you are able to make some settings to the tree structure that are not available in the other ALV tools.

You are able to make the following settings for hierarchy column :

Determining Column Header (Section: Determining Wording of the Column Header )
Inserting Icons into the Column Header (Section: Display Icon )
Determining the Tooltip for the Column Header (Section: Determining the Tooltip for the Column Header )
Define text for the node
Determine Icons for Expanded and Collapsed Branches
Display Leaf as Branch

You are able to make the following settings for nodes :

Get node objects
Generate, Move and Delete Nodes
Collapse and expand branches

You are able to make the following settings for items :

Determine value
Set Display of the Item
Set selectability

Features

For all of the following functions, this is valid:

ALV Tool	Display type	Function available
Simple, two-dimensional table	Classic ABAP List	No
Fullscreen	No
In the Container	No
Hierarchical-sequential list	Classic ABAP List	No
Tree Structure	Fullscreen	Yes
In the Container	Yes

Get Node Object

Each node is represented by an object of class CL_SALV_NODE, and all of the nodes together are represented by the object CL_SALV_NODES.

You get the references to the desired node object using various getter methods:

Function	Class	Method
All nodes together	CL_SALV_TREE	GET_NODES
List of all node objects and their key	CL_SALV_NODES	GET_ALL_NODES
Specific key	GET_NODE
Top node	GET_TOP_NODE
List of all subnodes and their key	CL_SALV_NODE	GET_SUBTREE GET_CHILDREN
Get key for the node	GET_KEY
Related nodes	GET_PARENT GET_FIRST_CHILD GET_LAST_CHILD GET_PREVIOUS_SIBLING GET_NEXT_SIBLING

Generate, Move and Delete Nodes

While you can display whole tables with one command using the ALV tools: simple, two-dimensional table and a hierarchical-sequential list , with the tree structure, you need to generate the nodes individually. To do this, provide at least the following:

The contents of the node that you wish to insert. The new node must have exactly the same structure as is specified in the initial table.
One reference nodeEvery node is uniquely identified by a key. If there is not yet a node in the tree structure, there will still be the top node. By default, the top node has an empty character string as the key. You insert the new node at a position relative to the reference node.
The relationship between the new node and the reference nodeYou are able to insert the new node at one of the following positions relative to the reference node:

Function	Class	Method
Add Node	CL_SALV_NODES	ADD_NODE
Change top node	SET_TOP_NODE
Move node to another position within the tree structure	CL_SALV_NODE	MOVE
Delete node with all of its subnodes	DELETE
Delete all nodes of the tree structure	CL_SALV_NODES	DELETE_ALL

Determine text in the hierarchy column

The hierarchy column is not part of the initial table. This means you are not able to control text in it with the contents of the data table. You determine the texts in the hierarchy column for each node individually.

Function	Class	Method
Determine text in the hierarchy column	CL_SALV_NODE	SET_TEXT
Get current text in the hierarchy column	GET_TEXT

Determine Icons for Expanded and Collapsed Branches

By default, a node that contains subnodes is indicated by an icon that looks like a folder. The icon looks different depending on whether the node is expanded or collapsed. You are able to use a different graphic for each icon. You determine both icons for each icon individually.

Function	Class	Method
Set icon for expanded branch	CL_SALV_NODE	SET_EXPANDED_ICON
Set icon for collapsed branch	SET_COLLAPSED_ICON
Get icon for expanded branch	GET_EXPANDED_ICON
Get icon for collapsed branch	GET_COLLAPSED_ICON

Display Leaf as Branch

For reasons of speed, you are able to display a node as a branch even if it does not contain subnodes. When the user expands the node, you insert the subnodes.

Note

A node that is displayed as a branch although it contains no subnodes is also called an empty folder.

Function	Class	Method
Instead of displaying the icon for leaves, show the icon for a collapsed branch	CL_SALV_NODE	SET_FOLDER
Check whether the node is an empty folder	IS_FOLDER
Display an expander in the empty folder	SET_EXPANDER
Check whether the empty folder has an expander	HAS_EXPANDER

Note

When the user expands an empty folder, the event EXPAND_EMPTY_FOLDER from the class CL_SALV_EVENTS_TREE is triggered.

Expand or Collapse Branches or Hide Areas

You are able to expand and collapse the branches of the tree structure individually or together. Beyond that you are able to make a node or an item completely invisible.

Function	Class	Method
Expand individual branch	CL_SALV_NODE	EXPAND
Collapse individual branch	COLLAPSE
Expand all branches	CL_SALV_NODES	EXPAND_ALL
Collapse all branches	COLLAPSE_ALL
Change visibility of a node	CL_SALV_NODE	SET_VISIBLE
Check whether the node is visible	IS_VISIBLE
Change visibility of an item	CL_SALV_ITEM	SET_VISIBLE
Check whether the item is visible	IS_VISIBLE

Change the Content of a Node or an Item

While you are modifying the contents of the two ALV tools simple, two-dimensional table and hierarchical-sequential list by making changes to the transferred table, changes also take place in the tree structure on the node or item level.

Note

If you exchange the content of the whole node, the structure of the new one must exactly match the one specified by the initial table.

Function	Class	Method
Change content of a node	CL_SALV_NODE	SET_DATA_ROW
Get content of a node	GET_DATA_ROW
Change contents of an item	CL_SALV_ITEM	SET_VALUE
Get content of an item	GET_VALUE

Set Display of the Item

In items of the tree structure you are able to display things other than text. With the type of the item, you are able to determine that one of the following elements be displayed in it:

Default setting
Text
Checkbox
Pushbutton
Link
Icons

For the types Checkbox (CHECKBOX), Pushbutton (BUTTON), and Link (LINK), there are events available to process interactions by the user.

Note

The user can only change the value of checkboxes that are enabled.

Function	Class	Method
Set type of an item	CL_SALV_ITEM	SET_TYPE
Get current type of the item	GET_TYPE
Change value of a checkbox	SET_CHECKED
Check value of a checkbox	IS_CHECKED
Enable checkbox so that the user can change the value interactively	SET_EDITABLE
Check whether a checkbox is enabled	IS_EDITABLE
Insert icon	SET_ICON
Get icon	GET_ICON

Example

To display an icon in an item, proceed as follows:

You assign the type Default (DEFAULT) to the item
You ensure that the content of the item is a permitted indicator for the desired icon (for example @AB@ )
Use the method SET_ICON in the CL_SALV_ITEM class.

Note

When the user changes the value of a checkbox, the event CHECKBOX_CHANGE from the class CL_SALV_EVENTS_TREE is triggered.
If the user clicks on an item of type Pushbutton (BUTTON) or Link (LINK), the event LINK_CLICK from the class CL_SALV_EVENTS_TREE is triggered.

Set selectability of an item

By default, the user is able to select an item by clicking on it or by pressing the tab key. You are able to determine that users cannot select an item.

Function	Class	Method
Set selectability of an item	CL_SALV_ITEM	SET_ENABLED
Check selectability	IS_ENABLED