ActionScript 3.0 Design Patterns.pdf - VideoTutorials-bg.com

Example 9-13. PlayMedia .as (continued)
}
}
vidUp.mediaProducer ( );
addChild (vidUp);
}
//Invoke the template method (mediaProducer) for the audio
private function getTune (e:MouseEvent):void
{
var tuneUp:VidAudio=new Audio( );
tuneUp.mediaProducer ( );
addChild (tuneUp);
}
Most of the work in this application has been done with ActionScript, but a Flash document
file will be used to create the buttons for the UI. The following steps show how:
1. Open a new Flash document and save it as PlayMedia.fla in the same folder as
the other files in the application.
2. Select Insert ➝ New Symbol from the menu bar.
3. In the New Symbol dialog box, select Button as the type. Type VideoButton in
the Name window, and click the Export for ActionScript checkbox. Click OK to
enter the Symbol editing mode.
4. Select the Rectangle tool, and set the Rectangle Corner Radius to 8. Draw a rectangle
with the dimensions W=49 and H=60.
5. Add a second layer while still in the Symbol editing mode. Name the top layer
“Text” and the bottom layer “Shape.” In the Text layer, add the static text label,
“Video.” Click OK.
6. Repeat Steps 2 to 5, substituting TuneButton for the button name, and “Tune” for
the static text label in Step 5.
7. Your Library panel should show two buttons, one named VideoButton and the
other named TuneButton. Each is considered a class, and instances of each are
used in the PlayMedia class.
To work with this application, you’ll need two additional files; an MP3 file and an
FLV file. Rename the MP3 file to iBlues.mp3 and the FLV file to media.flv.
Figure 9-5 shows the application running the video.
As you can see by this example, the “details” changed in the algorithm’s operations
can be extensive. Looking at the two main concrete classes, the methods handling the
video are far more extensive than those handling the audio. Not only does it include a
mechanism for starting the play, it also has a routine for extracting the metadata from
the FLV file, and displaying it on the stage in a text field. In contrast the path taken for
sound does not use the display array to add sound children. That’s because the sound
isn’t displayed on the stage, and so no display elements are required.
350 | Chapter 9: Template Method Pattern