Actionscript Cookbook

7.7. Checking for Mouseover

Problem

You want to check whether the mouse pointer is over a movie clip.

Solution

Use the onRollover( ) event handler, or use the hitTest( ) method within an onEnterFrame( ) method.

Discussion

In many cases, the onRollOver( ) and onRollOut( ) event handler methods, as shown in Recipe 7.5, are the easiest way to respond to the mouse pointer rolling over a movie clip. However, this technique fails when you drag one clip over another, such as when using a clip as a custom mouse pointer. Here is an example to illustrate the point:

// Include the DrawingMethods.as file from Chapter 4 for its drawRectangle(  ) and
// drawCircle(  ) methods.
#include "DrawingMethods.as"

// Create a rectangle_mc movie clip on the Stage.
_root.createEmptyMovieClip("rectangle_mc", 1);
rectangle_mc.lineStyle(1, 0x000000, 100);
rectangle_mc.beginFill(0, 100);
rectangle_mc.drawRectangle(100, 200, 10);
rectangle_mc.endFill(  );
rectangle_mc._x = 100;
rectangle_mc._y = 100;

// Create onRollOver(  ) and onRollOut(  ) methods such that when the mouse rolls on and
// off the movie clip, it goes to 50% transparency and back.
rectangle_mc.onRollOver = function (  ) {
  this._alpha = 50;
};

rectangle_mc.onRollOut = function (  ) {
  this._alpha = 100;
};

// Create a circle_mc movie clip.
_root.createEmptyMovieClip("circle_mc", 2);
circle_mc.lineStyle(1, 0x000000, 100);
circle_mc.beginFill(0xFFFFFF, 100);
circle_mc.drawCircle(50);
circle_mc.endFill(  );

// Create onPress(  ) and onRelease(  ) methods such ...