add frames p. 42
Every Flash movie contains multiple timelines. Every scene has a main Timeline, and each symbol has its own independent Timeline, as you saw when editing our background. Within a scene or symbol, each layer also has its own Timeline. In complex Flash movies like the one we're building, it is best to use the scene's main Timeline for organizational and reference purposes only. Use the timelines available inside symbols for animation.
We define two kinds of frames in a Timelinebasic frames and keyframes. Keyframes are where we do all of our work. Whenever you want to manually change the contents of a frame, you must do it in a keyframe. Basic frames make up what is known as a keyframe's spanthe frames between that keyframe and the next. Frames act merely as clones of the preceding keyframe.
By default, the first frame in any Timeline is a keyframe.
If you change an object in a frame, you're actually making that change to the keyframe and all frames in its span. It can be incredibly painful to make a change in a particular frame, thinking that you're only changing that frame, and 30 minutes later realize you actually changed 15 frames, so be careful that you are always editing in a keyframe.
In the Timeline, keyframes are marked with a bullet. A solid bullet signifies that the keyframe has contents, and a hollow bullet signifies an empty keyframe.The final frame in a keyframe span is marked with a hollow rectangle.
add frame labels p. 46
When you're working with multiple timelines throughout your movie, moving objects from place to place, and adding or removing frames as you work, it can be difficult to remember what frame number holds an object you're looking for or want to link to from elsewhere in the movie.
If you have objects on a keyframe at Frame 70 but then add 8 frames to the Timeline, your keyframe is now at 78. If buttons or other movie clips are linking to that keyframe by number, you have to remember to search them out and change the link from 70 to 78. But if you've labeled the keyframe important_frame, that doesn't change, and all the pointers in your movie are still correct.
It's a common practice in Flash development to add frames after a keyframe just to make enough room to display the frame label, making it easy to locate frames during development. In our Timeline so far, the only frames that will actually be seen by viewers are frames 1 and 11; the other frames will be bypassed. You'll understand this more when we add animations and navigation controlled with ActionScript later in the book.
control the timeline p. 47
ActionScript is Flash's powerful scripting language that allows developers to control playback, establish complex interactions, and even develop Flash-based applications. While it is considered an easy language to use, those of us who are not programmers don't necessarily think so.
In this book we'll avoid too much scripting by using very simple Actions (chunks of ActionScript) and Behaviors (prepackaged Actions) to control our timelines and provide navigation.
To help keep us organized, we add an empty layer named actions to each of our timelinesusing the layer only for labeling and ActionScript. This helps us keep the mechanics of our movie separate from the content and lets us visually track frame properties easily.