Setting Up SeekBar and VolumeBar Components
Let me demonstrate some more advanced methods for customizing your FLVPlayback Custom UI components through the use of ActionScript by focusing on two specific Custom UI components: the SeekBar and VolumeBar.
The SeekBar and VolumeBar components are similar, although they have different functions. Each has handles, uses the same handle-tracking mechanisms, and has support for clips nested within to track progress and fullness (see Figure 9).
Figure 9 The FLVPlayback component playing in the published SWF file
There are many places in which the ActionScript code in the FLVPlayback component assumes that the registration point of your SeekBar or VolumeBar component is at the upper-left corner of the content, so it is important to maintain this convention. Otherwise, you might have problems with handles and with progress and fullness movie clips (see Figure 10).
Figure 10 The registration point in the upper-left corner of the VolumeBar movie clip
Although the seek bars in the skin SWF files use 9-slice scaling because they need to be scaled at runtime, the SeekBar FLV custom UI component does not and cannot use 9-slice scaling because it has nested movie clips. If you want to make the SeekBar wider or taller, you should change its contents instead of scaling it.