| MovieClip.onSetFocus( ) Event Handler | Flash 6 |
| callback invoked when the clip gains focus |
The TextField, MovieClip, or Button object that previously had focus, or null if no object was previously focused.
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 to omit the () operator after the function name! delete clip_mc.onSetFocus;
The onSetFocus( ) handler normally is used to highlight an interface element when it has focus. For example, a dark blue dial can be colored light blue and surrounded with a black circle.
To capture all focus events centrally, rather than for a single instance, use Selection.onSetFocus( ).
Note that onSetFocus( ) cannot be used in a Flash 5-style onClipEvent( ) block.
The onSetFocus( ) handler does not work with main movie timelines (e.g., _root, _level1, _level2) because main timelines cannot receive input focus.
Button.onSetFocus( ), MovieClip.focusEnabled, MovieClip.onKillFocus( ), MovieClip.tabEnabled, Selection.onSetFocus( ), Selection.setFocus( ), TextField.onSetFocus( ); Chapter 10
