Foundation Flash CS5 For Designers- P16

Foundation Flash CS5 For Designers- P16: Flash is one of the most engaging, innovative, and versatile technologies available-allowing the creation of anything from animated banners and simple cartoons to Rich Internet Applications, interactive videos, and dynamic user interfaces for web sites, kiosks, devices, or DVDs. The possibilities are endless, and now it just got better
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Foundation Flash CS5 For Designers- P16 BUILDING STUFFhugging the left edge of SeekBar. As it is, however, the numbers are easy. To coordinate its movementswith SeekBar, all SeekKnob has to do is know SeekBar‘s horizontal position (seekBar.x) and take intoconsideration SeekBar’s width (seekBar.width).To position the knob along the bar’s left edge, all you need to do set its MovieClip.x property to the bar’sMovieClip.x property. To slide it halfway across, set the knob’s x property to the x property of the bar,plus half of the bar’s width. To shove it all the way over, set its x property to bar’s, plus the full width of thebar. Keep this principle in mind as we work through the seek slider ActionScript.To begin, copy another one of the commented code block headers and paste it below the last bit ofActionScript (nextHandler(), from the Buttons section). Change the header’s caption to Seek slider,and then type in the following ActionScript, so that your code looks like this:////////////////////////////////////////// Seek slider////////////////////////////////////////// prepseekKnob.buttonMode = true;// eventsseekKnob.addEventListener(MouseEvent.MOUSE_DOWN, seekStartDrag);Like the Prev, Play/Pause, and Next movie clip “buttons,” the seekKnob instance needs to have itsbuttonMode property set to true. When the user clicks it, you want the user to be able to start draggingthat knob, so the MouseEvent.MOUSE_DOWN event is associated with a custom function you’re about towrite, called seekStartDrag(). That function is triggered when the user clicks the mouse (MOUSE_DOWN)on the seekKnob instance. Type the following new ActionScript:function seekStartDrag(evt:MouseEvent):void { if (song != null) { pauseSong(); rect = new Rectangle(seekBar.x, seekKnob.y, seekBar.width, 0); seekKnob.startDrag(true, rect); stage.addEventListener(MouseEvent.MOUSE_UP, seekStopDrag); }};If the song instance isn’t null— for example, it’s null before a song is chosen from the combo box—thenpause the song, in case it’s playing. Next, define a Rectangle instance (stored in the rect variable),which will be used to constrain dragging to the desired location.Rectangle instances are specified at a particular location (x and y) and at a particular width and height. Inthis case, we want the knob to be draggable only from the left side of the bar (seekBar.x, the firstparameter) to the right side (seekBar.width, the third parameter). Its vertical position is fine where it is(seekKnob.y, the second parameter) and shouldn’t vary from that, which means we set the rectangle to aheight of 0 (the fourth parameter). 729 www.zshareall.com CHAPTER 14 The MovieClip.startDrag() method, invoked on seekKnob, is fed two parameters: true, which snaps dragging to the symbol’s registration point, and rect, which confines dragging to the dimensions just described. Finally, a MouseEvent.MOUSE_UP event handler is associated with the stage, configured to trigger a custom seekStopDrag() function. Why is this association made with the stage, rather than with seekKnob? Because the user might just drag the mouse off the knob before releasing the mouse (MOUSE_UP). If the event handler were associated with seekKnob, then seekStopDrag() wouldn’t be triggered. But when it’s assigned to the stage, that pretty much means the mouse can be lifted anywhere, and the dragging routine will stop. Here’s the seekStopDrag() function. Type the following new ActionScript: function seekStopDrag(evt:MouseEvent):void { seekKnob.stopDrag(); playSong(song.length * (seekKnob.x - seekBar.x) / seekBar.width); stage.removeEventListener(MouseEvent.MOUSE_UP, seekStopDrag); };This book was purchased by flashfast1@gmail.com ...