ActionScript for Flash MX: The Definitive Guide, Second Edition

MovieClip.onSetFocus() Event Handler

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ActionScript Language Reference

MovieClip.onSetFocus() Event Handler

callback invoked when the clip gains focus

Flash 6

mc.onSetFocus(oldFocus)

Arguments

oldFocus The TextField, MovieClip,orButton object that previously had focus, or null

if no object was previously focused.

Description

The onSetFocus() event handler is executed when mc gains focus. A clip gains focus when:

• The user navigates to the clip with the Tab key.

• Selection.setFocus() assigns focus programmatically.

A movie clip can be keyboard-focused under only one or more of the following

circumstances:

• It defines at least one button event handler (onPress(), onRollOver(), etc.).

• Its

tabEnabled property is true, in which case it can be focused by the Tab key.

• Its

focusEnabled property is true, in which case it can be focused by Selection.setFocus().

The following code registers a callback function that responds to onSetFocus():

// Assign the onSetFocus() callback using a function literal

theClip_mc.onSetFocus = function (newFocus) {

trace(this + " now has focus. Old focus was " + newFocus);

};

Notice that from the body of the callback, we can refer to theClip_mc using the this

keyword. To stop a callback from handling the onSetFocus() event, use the delete operator,

as in:

// Make sure ...