- Listening for Events
- Mouse Detection
- The SimpleButton Class
- Invisible Buttons
- Animated Buttons and the Movie Clip Symbol
- Complex Buttons
- Button-Tracking Options
- Changing Button Behavior
- Creating Buttons Dynamically
- Keyboard Detection
- The Contextual Menu
- Creating Continuous Actions
- A Summary of Events
This chapter is from the book
This chapter is from the book
This chapter is from the book
Complex Buttons
You can use a combination of invisible buttons, animated buttons, and movie clips to create objects with complex behaviors such as pull-down menus. The pull-down (or pop-up) menu is a kind of button that is common in operating systems and Web interfaces, and is useful for presenting several choices under a single heading. The functionality consists of a single button that expands to show more buttons and collapses when a selection has been made (Figure 4.28).
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Figure 4.28 Typical pull-down menus: a Mac OS system menu (left) and a Web menu (right).
To build your own pull-down menu, the basic strategy is to place buttons inside a movie clip. The buttons specify which frames within the movie clip timeline to play. Whether the menu is expanded or collapsed is determined within the movie clip. Placing an instance of this movie clip on the Stage allows you to access either the expanded or collapsed state independently of what's happening in your main movie.
To create a simple pull-down menu
- Create a button symbol that will be used for the top menu button as well as the choices in the expanded list.
- Add a filled rectangle to the Up, Over, Down, and Hit keyframes (Figure 4.29).
Figure 4.29 A generic button with the four keyframes defined.
Create a new movie clip symbol.
Enter symbol-editing mode for the movie clip.
Insert a new keyframe at a later point in the movie clip timeline.
You now have two keyframes. The first one will contain the collapsed state of your menu, and the second one will contain its expanded state (Figure 4.30).
Figure 4.30 The pull-down menu movie clip timeline contains two keyframes: one at frame 1 and another at frame 9.
Drag one instance of your button symbol into the first keyframe, and add text over the instance to describe the button.
This is the collapsed state of your menu.
Drag several instances of your button symbol into the second keyframe, align them with one another, and add text over these instances to describe the buttons.
This is the expanded state of your menu.
- Add a new layer, and place frame labels to mark the collapsed and expanded keyframes (Figure 4.31).
Figure 4.31 The two states of your pull-down menu. The collapsed state is in the first keyframe (top); the expanded state is in the second keyframe (bottom). The expanded state contains the initial button plus four button instances that represent the menu choices.
In the Frame Label field of the Property inspector, enter collapsed for the first keyframe and expanded for the second keyframe.
The frame labels let you see clearly the collapsed and expanded states of your movie clip and let you use the gotoAndStop() action with frame labels instead of frame numbers.
- Select the button instance in the first keyframe, and give it an instance name.
- Add a new layer; select the first keyframe in that layer, and open the Actions panel.
In the first line of the Script pane, add the action stop().
Without this stop() in the first frame of your movie clip, the menu would open and close repeatedly because of the automatic cycling of movie clips. The stop() action ensures that the movie clip stays on frame 1 until you click the menu button (Figure 4.32).
Figure 4.32 The movie clip timeline for the pull-down menu. A stop action is assigned to the first frame in the top layer.
- On the next line of the Script pane, add a function that goes to the expanded keyframe of the movie clip, like so:
stop(); function expandmenu(myevent: MouseEvent):void { this.gotoAndStop("expanded"); }When this function is called, the current timeline is targeted (with the keyword this) and the playhead goes to the frame labeled expanded. Make sure that the frame label is within quotation marks. - On the next available line of the Script pane, add an event listener for the button on the first keyframe of your movie clip:
pick_btn.addEventListener (MouseEvent.CLICK, expandmenu);
The listener listens for the mouse click on the button called pick_btn (Figure 4.33).
Figure 4.33 The stop action plus the event handler for the button in the first keyframe. When this button is clicked, Flash goes to the expanded keyframe.
- Select the first button instance on the last keyframe, and give it an instance name.
In the layer with your ActionScript, select the frame above the expanded keyframe, and add a new keyframe.
In this keyframe, you'll add the code for the buttons in the expanded menu.
You have to put more code here because you can't add event handler code to buttons until they're present on the Stage. Otherwise, Flash won't find the button instances and can't reference them from the code (Figure 4.34).
Figure 4.34 When buttons appear on a later frame (frame number 9), add a new keyframe at the same frame number with event handler code for those buttons.
- With your new keyframe selected, open the Actions panel and add a function that goes back to the collapsed keyframe like so:
function collapsemenu(myevent: MouseEvent):void { this.gotoAndStop("collapsed"); } - Next, add an event listener for the first button in the expanded keyframe:
pick2_btn.addEventListener (MouseEvent.CLICK, collapsemenu);
The listener listens for the mouse click on the button called pick2_btn (Figure 4.35).
Figure 4.35 The ActionScript for the buttons in the expanded keyframe sends the Flash playhead to the frame labeled collapsed and stops there.
- Assign instance names to each of the remaining button instances on this keyframe, and repeat steps 15–16 to add event handler code for each of them.
- Return to the main movie Timeline, and place an instance of your movie clip on the Stage.
Choose Control > Test Movie to see how your pull-down menu works.
When you click the first button, the buttons for your choices appear because you direct the playhead to go to the expanded keyframe on the movie clip timeline. When you click one of the buttons in the expanded state, the buttons disappear, returning you to the collapsed keyframe of the movie clip timeline. All this happens independently of the main movie Timeline, where the movie clip instance resides (Figure 4.36).
At this point, you've created a complex button that behaves like a pull-down menu but doesn't actually do anything (except modify itself). In Chapter 5, you'll learn how to make timelines communicate with one another, which enables you to create complex navigation systems.
Figure 4.36 The two states of the pull-down menu work independently of the main Timeline.
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