Handling Interaction 
ALV output is not just used to display data structures as tables to users. Users can also use ALV output interactively in various ways. You can provide the following options:
Standard ALV Functions
In the Settings dialog box or the toolbar, you can show or hide various UI elements with which the user can access the ALV output services.
Example
ALV supports the selection of standard functions: If, for example, your ALV output does not contain any columns with values that can be calculated, the UI elements for calculation are not displayed in the columns.
More information: Configuring Standard ALV Functions
User-defined, application-specific functions
You create UI elements in the toolbar with which the user can run the functions you programmed or standard ALV functions, and thus use your application effectively.
More information: Providing Application-Specific Functions
Interactive UI elements within the ALV output table
You can use interactive UI elements in the ALV output table (for example, as cell editors in the columns and cells of your ALV output). There are two types of interaction:
Interaction Without Data Change
More information: Handling Interaction Without Data Change)
Interaction with Data Change
More information: Handling Interaction with Editable ALV
Various events are available to handle users' actions for these UI elements.