Adobe 12040118 Using Help - Page 207

Adobe After Effects Help Using Help Creating User Interface Elements Back 207 Guidelines for creating and using modal dialogs When your script creates a dialog, you typically create controls that the user must interact with in order to enter values that your script will use. In general, you can minimize the number of event callback functions you attach to various controls in your dialogs, unless interaction with those controls changes the operation of the dialog itself. In most cases where you simply want to read the states of various controls when the dialog is dismissed, you do not need to handle events for them. For instance, you often don't need onClick() functions for every checkbox and radiobutton in your dialog: when the dialog is dismissed, read their states using their value properties. Some exceptions to this guideline: • onChange() functions are needed for edittext elements, if users enter values which must be validated (like a number within a range). The event callback must perform any necessary validation, and interact with the user on errors. • Define onClick() for OK and Cancel buttons which close the dialog with a given value. Note: Perform this function only if you have not defined the defaultElement and/or cancelElement properties or named these buttons in such a way that they will automatically be identified as the OK and Cancel buttons. Prompts and Alerts Some JavaScript environments provide functions on the global window object to display message boxes or alert boxes and a prompt box that displays one or two lines of text and then allows the user to enter one line of text. The scripting user interface defines functions alert(), confirm() and prompt() on the Window class that provides this standard functionality. The host application controls the appearance of these simple dialog boxes, so they are consistent with other alert and message boxes displayed by the application. See the "JavaScript UI reference" on page 213 for details. JavaScript UI example Having explored the individual scripting components that make up the user interface, you are now ready to see the parts assembled into real-world JavaScript code that produces a fully functional user interface. The JavaScript UI code sample described below includes the following functions, which creates a simple user interface builder window populated with various panels, checkboxes, buttons and controls. When you run the builder, you can then cause it to create an Alert Box. • createBuilderDialog() -- Creates an empty dialog window near the upper left of the screen and adds a title panel, a checkbox, a control panel and a panel with buttons to test parameters and create the Alert Box specification. • initializeBuilder() --Sets up initial control states and attaches event callback functions to controls. • runBuilder() -- Runs the builder dialog and returns the resulting Alert Box UI • createResource() -- Creates and returns a string containing a dialog resource specification that creates the Alert Box UI using the parameters entered • stringProperty() -- Returns a formatted string • arrayProperty() -- Returns a formatted array • createTestDialog() -- Creates a new Test dialog These functions are bundled together into a Main script, which assembles the final Alert Box dialog. Using Help Back 207