Tài liệu Flash: ActionScript Language Reference- P7 ppt

Example The following example illustrates the use of many of the MovieClipLoader class methods and listeners: // first set of listeners var my_mcl:MovieClipLoader = new MovieClipLoader;

MovieClipLoader class 601

Listener summary for the MovieClipLoader class

Constructor for the MovieClipLoader class

MovieClipLoader.onLoadComplete Invoked when a file loaded with MovieClipLoader.loadClip()

has completely downloaded.

MovieClipLoader.onLoadError Invoked when a file loaded with MovieClipLoader.loadClip()

has failed to load.

MovieClipLoader.onLoadInit Invoked when the actions on the first frame of the loaded clip

have been executed.

MovieClipLoader.onLoadProgress Invoked every time the loading content is written to disk during

the loading process.

MovieClipLoader.onLoadStart Invoked when a call to MovieClipLoader.loadClip() has

successfully begun to download a file.

The following example loads an image into a movie clip called image_mc The movie clip instance

is rotated and centered on the Stage, and both the Stage and movie clip have a stroke drawn around their perimeters

var w:Number = target_mc._width;

var h:Number = target_mc._height;

See also

The following example loads an image into a draggable, dynamically created movie clip called

image_mc The number of bytes loaded and the total number of bytes for the loaded image display in a dynamically created text field called filesize_txt

See also

MovieClipLoader.onLoadProgress

target The target path of a movie clip, or an integer specifying the level in Flash Player into which the movie will be loaded The target movie clip is replaced by the loaded SWF file

Using this method instead of loadMovie() or MovieClip.loadMovie() has a number of advantages The following handlers are implemented by the use on a listener object, which is registered with the MovieClipLoader class using

MovieClipLoader.addListener(listenerObject)

• The MovieClipLoader.onLoadStart handler is invoked when loading begins

• The MovieClipLoader.onLoadError handler is invoked if the clip cannot be loaded

• The MovieClipLoader.onLoadProgress handler is invoked as the loading process progresses

• The MovieClipLoader.onLoadInit handler is invoked after the actions in the first frame of the clip have executed, so you can begin manipulating the loaded clip

• The MovieClipLoader.onLoadComplete handler is invoked when a file has completed downloading

A SWF file or image loaded into a movie clip inherits the position, rotation, and scale properties

of the movie clip You can use the target path of the movie clip to target the loaded movie.You can use the method to load one or more files into a single movie clip or level;

MovieClipLoader.loadClip() 605

MovieClipLoader.getProgress() and MovieClipLoaderListener.onLoadProgress do not report the actual bytesLoaded and bytesTotal values in the Authoring player when the files are local When you use the Bandwidth Profiler feature in the authoring environment,

MovieClipLoader.getProgress() and MovieClipLoaderListener.onLoadProgress report the download at the actual download rate, not at the reduced bandwidth rate that the Bandwidth Profiler provides

Example

The following example illustrates the use of many of the MovieClipLoader class methods and listeners:

// first set of listeners

var my_mcl:MovieClipLoader = new MovieClipLoader();

var myListener:Object = new Object();

myListener.onLoadStart = function(target_mc:MovieClip) {

trace("*********First my_mcl instance*********");

trace("Your load has begun on movie clip = "+target_mc);

var loadProgress:Object = my_mcl.getProgress(target_mc);

trace(loadProgress.bytesLoaded+" = bytes loaded at start");

trace(loadProgress.bytesTotal+" = bytes total at start");

};

myListener.onLoadProgress = function(target_mc:MovieClip, loadedBytes:Number, totalBytes:Number) {

trace("*********First my_mcl instance Progress*********");

trace("onLoadProgress() called back on movie clip "+target_mc);

trace(loadedBytes+" = bytes loaded at progress callback");

trace(totalBytes+" = bytes total at progress callback");

};

myListener.onLoadComplete = function(target_mc:MovieClip) {

trace("*********First my_mcl instance*********");

trace("Your load is done on movie clip = "+target_mc);

var loadProgress:Object = my_mcl.getProgress(target_mc);

trace(loadProgress.bytesLoaded+" = bytes loaded at end");

trace(loadProgress.bytesTotal+" = bytes total at end");

};

myListener.onLoadInit = function(target_mc:MovieClip) {

trace("*********First my_mcl instance*********");

trace("Movie clip = "+target_mc+" is now initialized");

// you can now do any setup required, for example:

trace("ERROR CODE = "+errorCode);

trace("Your load failed on movie clip = "+target_mc+"\n");

};

my_mcl.addListener(myListener);

// Now load the files into their targets.

// loads into movie clips

this.createEmptyMovieClip("clip1_mc", this.getNextHighestDepth());

clip1_mc._x = 400;

this.createEmptyMovieClip("clip2_mc", this.getNextHighestDepth());

my_mcl.loadClip("http://www.macromedia.com/software/drk/images/box_drk5.jpg", clip1_mc);

// Second set of listeners

var another_mcl:MovieClipLoader = new MovieClipLoader();

var myListener2:Object = new Object();

myListener2.onLoadStart = function(target_mc:MovieClip) {

trace("*********Second my_mcl instance*********");

trace("Your load has begun on movie = "+target_mc);

var loadProgress:Object = my_mcl.getProgress(target_mc);

trace(loadProgress.bytesLoaded+" = bytes loaded at start");

trace(loadProgress.bytesTotal+" = bytes total at start");

};

myListener2.onLoadComplete = function(target_mc:MovieClip) {

trace("*********Second my_mcl instance*********");

trace("Your load is done on movie clip = "+target_mc);

var loadProgress:Object = my_mcl.getProgress(target_mc);

trace(loadProgress.bytesLoaded+" = bytes loaded at end");

trace(loadProgress.bytesTotal+" = bytes total at end");

};

myListener2.onLoadError = function(target_mc:MovieClip, errorCode:String) { trace("*********Second my_mcl instance*********");

trace("ERROR CODE = "+errorCode);

trace("Your load failed on movie clip = "+target_mc+"\n");

// Issue the following statements after the download is complete,

// and after my_mcl.onLoadInit has been called.

// my_mcl.removeListener(myListener);

// my_mcl.removeListener(myListener2);

See also

MovieClipLoader.unloadClip()

listenerObject A listener object that was added using MovieClipLoader.addListener().

target_mc A movie clip loaded by a MovieClipLoader.loadClip() method This parameter is optional

Returns

Nothing

Description

Listener; invoked when a file loaded with MovieClipLoader.loadClip() has completely

downloaded The value for target_mc identifies the movie clip for which this call is being made This is useful if multiple files are being loaded with the same set of listeners

This parameter is passed by Flash to your code, but you do not have to implement all of the parameters in the listener function

When you use the onLoadComplete and onLoadInit events with the MovieClipLoader class, it’s important to understand how this differs from the way they work with your SWF file The

onLoadComplete event is called after the SWF or JPEG file has loaded, but before the application has been initialized At this point it is impossible to access the loaded movie clip’s methods and properties, and because of this you cannot call a function, move to a specific frame, and so on In most situations, it’s better to use the onLoadInit event instead, which is called after the content has loaded and is fully initialized

Example

The following example loads an image into a movie clip instance called image_mc The

onLoadInit and onLoadComplete events are used to determine how long it takes to load the image The information displays in a dynamically created text field called timer_txt

target_mc.createTextField("timer_txt", target_mc.getNextHighestDepth(), 0, target_mc._height, target_mc._width, 22);

target_mc.timer_txt.text = "loaded in "+timerMS+" ms.";

};

var image_mcl:MovieClipLoader = new MovieClipLoader();

image_mcl.addListener(mclListener);

image_mcl.loadClip("http://www.macromedia.com/images/shared/product_boxes/ 112x112/box_studio_112x112.jpg", image_mc);

See also

MovieClipLoader.addListener(), MovieClipLoader.onLoadStart,

MovieClipLoader.onLoadError

listenerObject.onLoadError = function(target_mc:Object, errorCode:String) {

// your statements here

}

Parameters

listenerObject A listener object that was added using MovieClipLoader.addListener()

target_mc A movie clip loaded by a MovieClipLoader.loadClip() method

errorCode A string that explains the reason for the failure

Example

The following example displays information in the Output panel when an image fails to load This occurs when you test the following ActionScript, because the image does not exist in the specified location

this.createEmptyMovieClip("image_mc", this.getNextHighestDepth());

var mclListener:Object = new Object();

mclListener.onLoadError = function(target_mc:MovieClip, errorCode:String) { trace("ERROR!");

listenerObject A listener object that was added using MovieClipLoader.addListener().

target_mc A movie clip loaded by a MovieClipLoader.loadClip() method This parameter is optional

The value for target_mc identifies the movie clip this call is being made for This is useful if you are loading multiple files with the same set of listeners This optional parameter is passed to your ActionScript

Example

The following example loads an image into a movie clip instance called image_mc The

onLoadInit and onLoadComplete events are used to determine how long it takes to load the image This information displays in a text field called timer_txt

target_mc.timer_txt.text = "loaded in "+timerMS+" ms.";

};

var image_mcl:MovieClipLoader = new MovieClipLoader();

image_mcl.addListener(mclListener);

image_mcl.loadClip("http://www.macromedia.com/images/shared/product_boxes/ 112x112/box_studio_112x112.jpg", image_mc);

See also

MovieClipLoader.onLoadStart

listenerObject A listener object that was added using MovieClipLoader.addListener().

target_mc A movie clip loaded by a MovieClipLoader.loadClip() method This parameter is optional

loadedBytes The number of bytes that had been loaded when the listener was invoked

totalBytes The total number of bytes in the file being loaded

loadedBytes and totalBytes parameters

The value for target_mc identifies the movie clip this call is being made for This is useful if you are loading multiple files with the same set of listeners This optional parameter is passed to your ActionScript

Example

The following example creates a progress bar using the Drawing API The progress bar displays the loading progress of an image using the onLoadProgress listener When the image finishes loading, the progress bar is removed from the Stage You must replace the URL parameter of the

image_mcl.loadClip() command so that the parameter refers to a valid JPEG file using HTTP

If you attempt to use this example to load a local file that resides on your hard disk, this example will not work properly because, in test movie mode, Flash Player loads local files in their entirety Add the following ActionScript to your FLA or AS file:

listenerObject A listener object that was added using MovieClipLoader.addListener().

target_mc A movie clip loaded by a MovieClipLoader.loadClip() method This parameter is optional

Returns

Nothing

Description

Listener; invoked when a call to MovieClipLoader.loadClip() has successfully begun to download

a file The value for target_mc identifies the movie clip this call is being made for This is useful

if you are loading multiple files with the same set of listeners This optional parameter is passed to your ActionScript

Example

The following example loads an image into a movie clip instance called image_mc The

onLoadInit and onLoadComplete events are used to determine how long it takes to load the image This information displays in a text field called timer_txt

target_mc.timer_txt.text = "loaded in "+timerMS+" ms.";

};

var image_mcl:MovieClipLoader = new MovieClipLoader();

image_mcl.addListener(mclListener);

image_mcl.loadClip("http://www.macromedia.com/images/shared/product_boxes/ 112x112/box_studio_112x112.jpg", image_mc);

See also

MovieClipLoader.onLoadError, MovieClipLoader.onLoadInit, MovieClipLoader.onLoadComplete

Method; removes the listener that was used to receive notification when a MovieClipLoader

event handler was invoked No further loading messages will be received

start_button.enabled = true;

stop_button.enabled = false;

//

image_mcl.removeListener(mclListener); };

stop_button.enabled = false;

trace("\t name: "+target_mc._name);

trace("\t url: "+target_mc._url);

Variable; a predefined variable with the IEEE-754 value for NaN (not a number) To determine if

a number is NaN, use isNaN()

Constant; specifies the IEEE-754 value representing negative infinity The value of this constant

is the same as Number.NEGATIVE_INFINITY

CHAPTER 2

ActionScript Language Reference

NetConnection class

Availability

Flash Player 7

Note: This class is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Description

The NetConnection class provides the means to play back streaming FLV files from a local drive

or HTTP address For more information on video playback, see “Playing back external FLV files

dynamically” in Using ActionScript in Flash

Method summary for the NetConnection class

Constructor for the NetConnection class

Availability

Flash Player 7

Note: This class is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see your Flash Communication Server documentation.

Constructor; creates a NetConnection object that you can use in conjunction with a NetStream

object to play back local streaming video (FLV) files After creating the NetConnection object,

use NetConnection.connect() to make the actual connection

Playing external FLV files provides several advantages over embedding video in a Flash document,

such as better performance and memory management, and independent video and Flash frame

NetConnection.connect() Opens a local connection through which you can play back video

(FLV) files from an HTTP address or from the local file system.

CHAPTER 2

ActionScript Language Reference

NetConnection class 623 See also

NetStream class, Video.attachVideo()

Availability

Flash Player 7

Note: This method is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

NetStream class 625

NetStream class

Availability

Flash Player 7

Note: This class is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Description

The NetStream class provides methods and properties for playing Flash Video (FLV) files from

the local file system or an HTTP address You use a NetStream object to stream video through a

NetConnection object Playing external FLV files provides several advantages over embedding

video in a Flash document, such as better performance and memory management, and

independent video and Flash frame rates This class provides a number of methods and properties

you can use to track the progress of the file as it loads and plays, and to give the user control over

playback (stopping, pausing, and so on)

For more information on video playback, see “Playing back external FLV files dynamically” in

Using ActionScript in Flash.

Method summary for the NetStream class

The following methods and properties of the NetConnection and NetStream classes are used to

control FLV playback

Property summary for the NetStream class

NetStream.close() Closes the stream but does not clear the video object.

NetStream.pause() Pauses or resumes playback of a stream.

NetStream.play() Begins playback of an external video (FLV) file.

NetStream.seek() Seeks a specific position in the FLV file.

NetStream.setBufferTime() Specifies how long to buffer data before starting to display the stream.

NetStream.bufferLength The number of seconds of data currently in the buffer.

NetStream.bufferTime Read-only; the number of seconds assigned to the buffer by

NetStream.currentFps The number of frames per second being displayed.

NetStream.time Read-only; the position of the playhead, in seconds.

CHAPTER 2

ActionScript Language Reference

Event handler summary for the NetStream class

Constructor for the NetStream class

Availability

Flash Player 7

Note: This class is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

var connection_nc:NetConnection = new NetConnection();

NetConnection class, NetStream class, Video.attachVideo()

NetStream.onStatus Invoked every time a status change or error is posted for the

NetStream object.

NetStream.bufferLength 627

NetStream.bufferLength

Availability

Flash Player 7

Note: This property is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Example

The following example dynamically creates a text field that displays information about the number of seconds that are currently in the buffer The text field also displays the buffer length that the video is set to, and percentage of buffer that is filled

this.createTextField("buffer_txt", this.getNextHighestDepth(), 10, 10, 300, 22);

var output_str:String = "<textformat tabStops='[100,200]'>";

output_str += "Length: "+my_ns.bufferLength+"\t"+"Time:

Availability

Flash Player 7

Note: This property is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Example

The following example dynamically creates a text field that displays information about the number of seconds that are currently in the buffer The text field also displays the buffer length that the video is set to, and percentage of buffer that is filled

this.createTextField("buffer_txt", this.getNextHighestDepth(), 10, 10, 300, 22);

var output_str:String = "<textformat tabStops='[100,200]'>";

output_str += "Length: "+my_ns.bufferLength+"\t"+"Time:

The following example creates a progress bar using the Drawing API and the bytesLoaded and

bytesTotal properties that displays the loading progress of video1.flv into the video object instance called my_video A text field called loaded_txt is dynamically created to display information about the loading progress as well

var connection_nc:NetConnection = new NetConnection();

this.createEmptyMovieClip("progressBar_mc", this.getNextHighestDepth()); progressBar_mc.createEmptyMovieClip("bar_mc",

var loaded_interval:Number = setInterval(checkBytesLoaded, 500, stream_ns); function checkBytesLoaded(my_ns:NetStream) {

var pctLoaded:Number = Math.round(my_ns.bytesLoaded/my_ns.bytesTotal*100); loaded_txt.text = Math.round(my_ns.bytesLoaded/1000)+" of

"+Math.round(my_ns.bytesTotal/1000)+" KB loaded ("+pctLoaded+"%)";

The following example creates a progress bar using the Drawing API and the bytesLoaded and

bytesTotal properties that displays the loading progress of video1.flv into the video object instance called my_video A text field called loaded_txt is dynamically created to display information about the loading progress as well

var connection_nc:NetConnection = new NetConnection();

this.createEmptyMovieClip("progressBar_mc", this.getNextHighestDepth()); progressBar_mc.createEmptyMovieClip("bar_mc",

NetStream.close() 633

NetStream.close()

Availability

Flash Player 7

Note: This method is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Availability

Flash Player 7

Note: This property is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

var fps_interval:Number = setInterval(displayFPS, 500, stream_ns);

function displayFPS(my_ns:NetStream) {

fps_txt.text = "currentFps (frames per second):

"+Math.floor(my_ns.currentFps);

}

NetStream.onStatus 635

NetStream.onStatus

Availability

Flash Player 7

Note: This handler is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Usage

my_ns.onStatus = function(infoObject:Object) : Void{

// Your code here

}

Parameters

infoObject A parameter defined according to the status or error message For more

information about this parameter, see “Description,” below

Returns

Nothing

Description

Event handler; invoked every time a status change or error is posted for the NetStream object

If you want to respond to this event handler, you must create a function to process the

information object

The information object has a code property containing a string that describes the result of the

onStatus handler, and a level property containing a string that is either status or error

In addition to this onStatus handler, Flash also provides a “super” function called

System.onStatus If onStatus is invoked for a particular object and there is no function assigned

to respond to it, Flash processes a function assigned to System.onStatus if it exists

The following events notify you when certain NetStream activities occur

If you consistently see errors regarding buffer, you should try changing the buffer using the NetStream.setBufferTime() method

NetStream.Buffer.Empty status Data is not being received quickly enough to fill

the buffer Data flow will be interrupted until the buffer refills, at which time a

NetStream.Buffer.Full message will be sent and the stream will begin playing again.

NetStream.Buffer.Full status The buffer is full and the stream will begin

playing

NetStream.Play.Start status Playback has started.

NetStream.Play.Stop status Playback has stopped.

NetStream.Play.StreamNotFound error The FLV passed to the play() method can't be

found.

The following example displays data about the stream in the Output panel:

var connection_nc:NetConnection = new NetConnection(); connection_nc.connect(null);

var stream_ns:NetStream = new NetStream(connection_nc); my_video.attachVideo(stream_ns);

NetStream.pause() 637

NetStream.pause()

Availability

Flash Player 7

Note: This method is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

Usage

my_ns.pause( [ pauseResume:Boolean ] ) : Void

Parameters

pauseResume A Boolean value specifying whether to pause play (true) or resume play (false)

If you omit this parameter, NetStream.pause() acts as a toggle: the first time it is called on a specified stream, it pauses play, and the next time it is called, it resumes play This parameter is optional

Returns

Nothing

Description

Method; pauses or resumes playback of a stream

The first time you call this method (without sending a parameter), it pauses play; the next time, it resumes play You might want to attach this method to a button that the user presses to pause or resume playback

Example

The following examples illustrate some uses of this method:

my_ns.pause(); // pauses play first time issued

my_ns.pause(); // resumes play

my_ns.pause(false); // no effect, play continues

my_ns.pause(); // pauses play

See also

NetStream.close(), NetStream.play()

Availability

Flash Player 7

Note: This method is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

If you want to control the audio associated with an FLV file, you can use

MovieClip.attachAudio() to route the audio to a movie clip; you can then create a Sound object to control some aspects of the audio For more information, see MovieClip.attachAudio()

If the FLV file can’t be found, the NetStream.onStatus event handler is invoked If you want to stop a stream that is currently playing, use NetStream.close()

You can play local FLV files that are stored in the same directory as the SWF file or in a

subdirectory; you can’t navigate to a higher-level directory For example, if the SWF file is located

in a directory named /training, and you want to play a video stored in the /training/videos directory, you would use the following syntax:

my_ns.play("videos/videoName.flv");

To play a video stored in the /training directory, you would use the following syntax:

my_ns.play("videoName.flv");

Example

The following example illustrates some ways to use the NetStream.play() command:

// Play a file that is on the user’s computer

// The joe_user directory is a subdirectory of the directory

NetStream.play() 639

See also

MovieClip.attachAudio(), NetStream.close(), NetStream.pause(),

Video.attachVideo()

Availability

Flash Player 7

Note: This method is also supported in Flash Player 6 when used with Flash Communication Server

For more information, see the Flash Communication Server documentation.

• To return to the beginning of the stream, pass 0 for numberOfSeconds

• To seek forward from the beginning of the stream, pass the number of seconds you want to advance For example, to position the playhead at 15 seconds from the beginning, use

my_ns.seek(15)

• To seek relative to the current position, pass my_ns.time + n or my_ns.time - n to seek n

seconds forward or backward, respectively, from the current position For example, to rewind 20 seconds from the current position, use my_ns.seek(my_ns.time - 20).

The precise location to which a video seeks will differ depending on the frames per second setting

at which it was exported Therefore, if the same video is exported at 6 fps and 30 fps, it will seek

to two different locations if you use, for example, my_ns.seek(15) for both video objects

The following example illustrates some ways to use the NetStream.seek() command:

// Return to the beginning of the stream