Now, you're ready to add the ActionScript code necessary to load an external .flv file, and display it in the vWin instance. Select frame 1 of the actions layer, and open the Actions panel (F9, Option+F9). Change the code to that shown in Listing 28-7.
Listing 28-7: Creating a NetStream Object to Access Flash Video Content
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1. var cbtLoad:mx.controls.Button;
2. var cbtUnload:mx.controls.Button;
3. var tVid:TextField;
4. var vWin:Video;
5.
6. var nc:NetConnection = new NetConnection();
7. nc.connect(null);
8.
9. var ns:NetStream = new NetStream(nc);
10.
11. ns.onStatus = function(oInfo:Object):Void {
12. trace("ns.onStatus >");
13. trace("\tlevel:\t" +oInfo.level);
14. trace("\tcode:\t" + oInfo.code);
15. };
16.
17. ns.onMetaData = function(oData:Object):Void {
18. trace("ns.onMetaData >");
19. trace("\twidth: "+ oData.width);
20. trace("\theight: "+ oData.height);
21. trace("\tduration: "+ oData.duration);
22. };
23.
24. ns.setBufferTime(5);
25. vWin.attachVideo(ns);
26.
27. var oLoader:Object = new Object();
28. oLoader.click = function(oEvent:Object):Void {
29. var sLabel:String = oEvent.target.label.toLowerCase();
30. if(sLabel == "load flv"){
31. ns.play(tVid.text);
32. } else if (sLabel == "unload flv"){
33. ns.close();
34. vWin.clear();
35. }
36. };
37.
38. cbtLoad.addEventListener("click", oLoader);
39. cbtUnload.addEventListener("click", oLoader);
40.
41. focusManager.defaultPushButton = cbtLoad;
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In lines 1 through 4, the data types of elements on the Stage are updated to reflect the current contents.
In lines 6 through 7, a new NetConnection instance named nc is created. This object is required as the sole parameter of the NetStream constructor (line 9). In line 7, the nc instance is connected to a null URL. If you were streaming content from a Flash Communication Server application or Flash Video Streaming Service, you would specify an RTMP location here. For progressively downloaded .flv files from a standard Web server, though, you simply connect to a null location.
In line 9, a new NetStream instance named ns is created. A NetStream instance is required to play an FLV file.
In lines 11 through 15, an onStatus() handler is defined for the ns object. This handler is invoked whenever an event occurs on the stream. In this example, the handler simply outputs trace() messages to the Output panel, letting you know what's happening with the stream.
| Note |
The \t backslash pairs shown in the trace() actions enable you to shift trace messages to the right, inserting tab characters. You'll see the effect of each \t when you test the movie.
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Lines 17 through 22 define the onMetaData() handler for the NetStream instance. This handler is invoked when the .flv file's metadata is received. The metadata is at the front of the .flv file. As such, this handler invokes before the video begins to play. The file's metadata includes information describing the media file, including its width, height, and duration.
On line 24, a buffer time is set for the stream. This value determines how many seconds of the stream must download before playback begins.
In line 25, the attachVideo() method of the Video class is invoked on the vWin instance, the object you placed on the Stage in Step 8. The parameter for the attachVideo() method is the instance name of the NetStream object created in line 9.
Like previous examples, the behavior for each Button component is tied to respective if/else statements within the click() handler of the listener object, oLoader. If the cbtLoad instance is clicked, then lines 30 and 31 are invoked. In line 31, the play() method of the NetStream class is invoked on the ns instance. For .flv files that are not accessed from a Flash Communication Server application, the parameter for the play() method is the HTTP-based URL of the .flv file. You can use relative or absolute paths for this URL. In our example, you use the text from the tVid field to determine the URL.
In lines 32 through 34, the video file's playback is stopped. This code is invoked when the cbtUnload instance is clicked. In line 33, playback of the stream is stopped by invoking the close() method of the ns instance, and the image in the Video instance, vWin, is erased with the clear() method.
In line 41, you set the focusManager class's defaultPushButton property to the cbtLoad instance. This action enables the Enter key for the cbtLoad instance. When you test the movie, make sure you choose Control ð Disable Keyboard Shortcuts to remap the Enter key to the Flash movie.
| Note |
The focusManager class is automatically available in your Flash movies whenever you add User Interface components to your Flash movie.
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