Components provide a lot of freedom to users with regards to packaging re-usable content. However, there are some guidelines that if followed will reduce the potential for confusion when your component is applied to a number of projects.
While it is possible to create components from a single control, this is generally only useful for the simplest of components. In order to manage interactive state, provide feedback and handle input it is better to use a group to provide a consistent namespace for controls and variables.
Components are intended to be created in the context of one project and then shared and used in other projects. However, since a component packages all of its images, fonts, scripts and animations with it, there is always the potential for name conflicts to occur. To minimize the change of conflict it is suggested that you name all of resources with a prefix that links them to component. For example Crank provided components use following naming convention:
A prefix name is established using a prefix of SBC
followed by the name of the component. For example SBCPushButton
All image resources use the prefix name (e.g.,
SBCPushButtonBevel.png
)
All animation definitions use the prefix name (e.g.,
SBCPushButtonFadeOut
)
All Lua script files use the prefix name (e.g., SBCPushButton.lua
)
In order to avoid any conflict within the Lua namespace it is important to not only
identify the Lua script file(s) used by the component but also to ensure that all of the Lua functions
and variables used by the component do not conflict with anything else in the application. This means
ensuring only a minimal set of callback functions are exposed and that the local
keyword
is rigorously applied.
callback
VariableIn many component situations is it desirable to remove the user from the mechanics
of what a component is doing within the UI and to simply provide status information as a final result.
For example a check-box button might have a selected/unselected state or a slider might have a
percentage result that they indicate. In these cases it is a convention to use a variable
associated with the group named callback
that is typed as a Lua function
variable. This allows the user to set different callback functions for different instances of
the component but use the same controlling logic.