Actionscript AIR应用程序:无法访问空对象引用的属性或方法。不知道是什么';这是什么原因造成的
我正在使用开源MP3播放器Howler的代码,并尝试将其移植到Spark MobileApplication类型。我得到一个空指针异常,我不知道是什么导致它。我尝试过在我认为导致错误的地方使用断点进行大量调试,并在未触及的Howler项目中设置断点,但范围内的所有变量在我的非工作项目和Howler项目之间似乎是相同的。我唯一能想到的是Howler使用MX组件,而我使用的是spark。我已经在下面粘贴了我所有的代码(非常长),但是我已经加粗了抛出错误的行。在“浏览文件夹”对话框中选择文件夹后,该错误立即发生Actionscript AIR应用程序:无法访问空对象引用的属性或方法。不知道是什么';这是什么原因造成的,actionscript,null,air,Actionscript,Null,Air,我正在使用开源MP3播放器Howler的代码,并尝试将其移植到Spark MobileApplication类型。我得到一个空指针异常,我不知道是什么导致它。我尝试过在我认为导致错误的地方使用断点进行大量调试,并在未触及的Howler项目中设置断点,但范围内的所有变量在我的非工作项目和Howler项目之间似乎是相同的。我唯一能想到的是Howler使用MX组件,而我使用的是spark。我已经在下面粘贴了我所有的代码(非常长),但是我已经加粗了抛出错误的行。在“浏览文件夹”对话框中选择文件夹后,该错
<?xml version="1.0" encoding="utf-8"?>
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark" title="Home"
xmlns:Comp="components.*" xmlns:display="flash.display.*">
<s:Button id="browse" x="546" y="43" label="Open Directory" click="browseForFolder()"/>
<s:DataGrid id="dgPlaylist" width="82" height="141" itemRenderer="components.DurationFormatter">
</s:DataGrid>
<s:Button id="btnForward" x="187" y="126" label="Forward"/>
<s:Button id="btnPause" x="90" y="39" label="Pause"/>
<s:Button id="btnBack" x="55" y="166" label="Back" click="changeSoundIndex(-1)"/>
<s:Button id="btnPlay" x="336" y="199" label="Button"/>
<s:Button id="btnStop" x="366" y="89" label="Stop"/>
<s:VScrollBar id="sldrPosition" x="280" y="43" mouseDown="thumbTimer.stop()"
mouseUp="thumbTimer.start()"
/>
<s:VScrollBar id="sldrVolume" x="265" y="234" change="ChangeSoundTransform()"
/>
<s:RichText id="txtID3" x="236" y="41" width="99">
</s:RichText>
<fx:Declarations>
</fx:Declarations>
<fx:Script>
<![CDATA[
import com.ericcarlisle.PlayList;
import com.ericcarlisle.PlayModes;
import com.ericcarlisle.Utility;
import flash.desktop.NativeDragManager;
import flash.media.Sound;
import mx.core.UIComponent;
import mx.events.CloseEvent;
import mx.events.DragEvent;
import org.osmf.traits.PlayTrait;
import spark.components.DataGrid;
// Player properties
private var playMode:String = "STOP";
private var volume:uint;
private const panning:int = 0;
private var selectedFileCount:uint;
private var loadedFileCount:uint;
private var soundIndex:uint;
// Player objects
private var SoundObj:Sound;
private var Channel:SoundChannel;
private var Transform:SoundTransform;
private var thumbTimer:Timer;
private var PlayList:com.ericcarlisle.PlayList;
private var SoundFilter:FileFilter = new FileFilter("Sounds", "*.mp3;*.wav");
//private var PlaylistFilter:FileFilter = new FileFilter("Sounds", "*.pls;*.m3u");
// Visualization objects.
private var Spectrum:ByteArray;
private const VISUALIZER_HEIGHT:Number = 50;
private const VISUALIZER_COLOR:Number = 0x336699;
// ID3 and other metadata
private var ID3:ID3Info;
private var Duration:int;
/*---------- PLAYER INITIALIZER ----------*/
// Initialization function used to add event handlers and set initial settings.
private function init():void
{
// Set player initial settings.
playMode = PlayModes.STOP;
selectedFileCount = 0;
loadedFileCount = 0;
soundIndex = 0;
// Set initial application height.
//this.height= cvsControlBar.height + cvsPlayer.height;
// Set volume.
volume = sldrVolume.value;
// Instantiate sound objects.
Channel = new SoundChannel();
Transform = new SoundTransform(volume/100, panning);
PlayList = new com.ericcarlisle.PlayList();
// Bind playlist data to datagrid.
dgPlaylist.dataProvider = PlayList.Sounds;
// Create a timer to control the song position hslider.
thumbTimer = new Timer(500);
thumbTimer.addEventListener(TimerEvent.TIMER, onTimerTick);
// Create event handlers for application.
this.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
this.addEventListener(Event.ENTER_FRAME, onEnterFrame);
this.addEventListener(NativeDragEvent.NATIVE_DRAG_ENTER, onPlayerDragInto);
this.addEventListener(NativeDragEvent.NATIVE_DRAG_DROP, onPlayerDropInto);
this.addEventListener(InvokeEvent.INVOKE, onInvoke);
}
/*---------- DRAG/DROP & FILE MANAGEMENT ----------*/
private function onInvoke(event:InvokeEvent):void
{
if (event.arguments.length > 0)
{
var file:File;
var files:Array = new Array();
for (var i:int = 0; i < event.arguments.length; i++)
{
file = new File(event.arguments[i]);
files.push(file);
}
if (PlayList.Sounds.length > 0) removeAllSounds();
loadFiles(files);
}
}
// Handles file selection event dispatched by browse dialog.
private function onFileSelect(event:FileListEvent):void
{
loadFiles(event.files);
}
// Handles folder selection event dispatched by browse dialog.
private function onDirectorySelect(event:Event):void
{
var directory:File = event.target as File;
**loadFiles(directory.getDirectoryListing());**
}
// Loads a batch of files into the playlist.
private function loadFiles(files:Array):void
{
var file:File;
// Count the number of files selected. Only accept files with .mp3 extension.
selectedFileCount = 0;
for (var i:uint = 0; i < files.length; i++)
{
file = files[i];
if (file.extension == "mp3") selectedFileCount++;
}
// Reset the count on files currently loaded.
loadedFileCount = 0;
**// Set the player mode so that loaded files are played automatically.
if (PlayList.Sounds.length == 0) playMode = PlayModes.LOADTOPLAY;**
// Load files as sound objects.
for(var j:uint = 0; j < files.length; j++)
{
file = files[j];
if (file.extension == "mp3" || file.extension == "wav")
{
var sound:Sound = new Sound(new URLRequest(file.url));
sound.addEventListener(Event.ID3,onID3);
}
}
}
// Presents file browse (multiple file) dialog.
private function browseForFiles():void
{
var SoundFile:File = new File();
SoundFile.browseForOpenMultiple("Open", [SoundFilter]);//, PlaylistFilter]);
SoundFile.addEventListener(FileListEvent.SELECT_MULTIPLE, onFileSelect);
}
// Presents file browse (folder) dialog.
private function browseForFolder():void
{
var directory:File = File.documentsDirectory;
directory.browseForDirectory("Select Directory");
directory.addEventListener(Event.SELECT, onDirectorySelect);
}
// Accept files dragged into player.
private function onPlayerDragInto(event:Event):void
{
NativeDragManager.acceptDragDrop(this);
}
// Manages files dropped into player.
private function onPlayerDropInto(event:NativeDragEvent):void
{
// Accept only files.
if (event.clipboard.hasFormat(ClipboardFormats.FILE_LIST_FORMAT))
{
// Parse dragged contents into array of files.
var dragFiles:Array = event.clipboard.getData(ClipboardFormats.FILE_LIST_FORMAT) as Array;
// Load the files.
loadFiles(dragFiles);
}
}
/*---------- SOUND MANAGEMENT ----------*/
private function loadSound():void
{
SoundObj = new Sound();
SoundObj.load(new URLRequest(PlayList.Sounds[soundIndex]["url"]));
SoundObj.addEventListener(Event.COMPLETE, onSoundLoaded);
}
private function onSoundLoaded(event:Event):void
{
// Retrieve data for current sound from playlist.
var soundData:Object = PlayList.Sounds[soundIndex];
// Place ID3 information into the readout panel.
//txtID3.htmlText = Utility.ReadoutHTML(soundData["title"], soundData["track"], soundData["album"], soundData["artist"], soundData["year"], soundData["duration"]);
// Configure the holizontal slider to act as a playhead.
sldrPosition.maximum = soundData["duration"];
// Set the selected row in the playlist display.
dgPlaylist.selectedIndex = soundIndex;
// Start the player if the mode is correct.
if (playMode == PlayModes.LOADTOPLAY)
{
playSound();
}
else
{
playMode = PlayModes.LOADED;
}
}
// Plays the current sound.
public function playSound():void
{
// Load sound into channel.
Channel.stop();
Channel = SoundObj.play(sldrPosition.value,0,Transform);
playMode = PlayModes.PLAY;
// Start position timer.
thumbTimer.start();
// Configure UI controls.
btnPlay.visible = false;
btnPause.visible = true;
sldrPosition.enabled = true;
btnPlay.enabled = true;
btnStop.enabled = true;
setBackForwardButtons();
Channel.addEventListener(Event.SOUND_COMPLETE, onSoundComplete);
}
private function setBackForwardButtons():void
{
if (soundIndex == PlayList.Sounds.length-1 || PlayList.Sounds.length == 0)
{
btnForward.enabled = false;
}
else
{
btnForward.enabled = true;
}
if (soundIndex == 0 || PlayList.Sounds.length == 0)
{
btnBack.enabled = false;
}
else
{
btnBack.enabled = true;
}
}
// Stops the current sound.
public function stopSound():void
{
Channel.stop();
thumbTimer.stop();
sldrPosition.value = 0;
playMode = PlayModes.STOP;
//Visualizer.graphics.clear();
btnPlay.visible = true;
btnPause.visible = false;
}
// Pause a playing sound.
private function pauseSound():void
{
Channel.stop();
thumbTimer.stop();
btnPlay.visible = true;
btnPause.visible = false;
}
// Change the sound index
private function changeSoundIndex(delta:int):void
{
stopSound();
playMode = PlayModes.LOADTOPLAY;
soundIndex = soundIndex + delta;
loadSound();
}
// Change the volume and panning via the sound transform object.
private function ChangeSoundTransform():void
{
volume = Math.round(sldrVolume.value);
Channel.soundTransform = new SoundTransform(volume/100, panning);
}
// Handles event for sound completing.
private function onSoundComplete(event:Event):void
{
stopSound();
soundIndex++;
if (soundIndex < PlayList.Sounds.length)
{
playMode = PlayModes.LOADTOPLAY;
loadSound();
}
}
// Load ID3 information into local variables.
// Update the readout panel.
// Configure position slider.
private function onID3(event:Event):void
{
var sound:Sound = Sound(event.target);
ID3 = ID3Info(sound.id3);
Duration = Math.floor(sound.length);
// Load sound id3 data into the playlist.
PlayList.AddSound(ID3.songName, ID3.album, ID3.artist, ID3.track, ID3.year, ID3.genre, Duration, sound.url);
// Increment the loaded file count.
loadedFileCount++;
if (loadedFileCount == selectedFileCount * 2)
{
// Refresh the playlist so that new results will be visually displayed.
PlayList.Sounds.refresh();
// Set the count properties.
selectedFileCount = 0;
loadedFileCount = 0;
soundIndex = 0;
if (playMode == PlayModes.LOADTOPLAY) loadSound();
}
}
/*---------- VISUALIZATION ----------*/
private function UpdateVisualizer():void
{
// Instantiate a new byte array to contain spectrum data.
Spectrum = new ByteArray();
// Clear the visualizer graphics.
//Visualizer.graphics.clear();
// Dump the spectrum data into the byte array.
SoundMixer.computeSpectrum(Spectrum,false,0);
var f:Number;
var i:int;
var ave:int;
//Visualizer.graphics.lineStyle(1, VISUALIZER_COLOR,1);
//Visualizer.graphics.beginFill(VISUALIZER_COLOR, 0.75);
for (i = 0; i < 512; i=i+10)
{
f = Spectrum.readFloat();
//Visualizer.drawRoundRect(Math.floor(i*0.7) + 7, cvsReadout.height - 10, 4, -Math.abs(f) * (cvsReadout.height-10));
}
//Visualizer.graphics.endFill();
}
// Updates the position of the hslider thumb.
private function onTimerTick(event:TimerEvent):void
{
sldrPosition.value = Math.round(Channel.position);
}
// Update the wave visualizer if the sound is playing.
private function onEnterFrame(event:Event):void
{
if (playMode == PlayModes.PLAY)
{
UpdateVisualizer();
}
}
// Show application information.
private function showHowlerInfo():void
{
//cvsAbout.visible = true;
}
private function togglePlayList():void
{
}
private function onItemDoubleClick(event:Event):void
{
this.playMode = PlayModes.LOADTOPLAY;
thumbTimer.stop();
sldrPosition.value = 0;
loadSound();
}
/*---------- ERROR HANDLING ----------*/
// Handles IO errors.
private function onIOError(event:IOErrorEvent):void
{
//Alert.show("File load error: " + event.text);
}
private function startMove():void
{
stage.nativeWindow.startMove();
}
private function unloadSound():void
{
stopSound();
txtID3.text = "";
btnPlay.visible = true;
btnPause.visible = false;
btnPlay.enabled = false;
btnStop.enabled = false;
}
private function removeSound():void
{
var index:int = dgPlaylist.selectedIndex;
if (index >= 0)
{
if (index == soundIndex)
{
unloadSound();
}
PlayList.RemoveSoundAt(index);
PlayList.Sounds.refresh();
setBackForwardButtons();
}
}
private function removeAllSounds():void
{
unloadSound();
PlayList.Sounds.removeAll();
PlayList.Sounds.refresh();
setBackForwardButtons();
}
private function onKeyDown(event:KeyboardEvent):void
{
if (event.charCode.toString() == "8" || event.charCode.toString() == "127")
{
removeSound();
}
}
]]>
</fx:Script>
</s:View>
0)
{
var文件:文件;
var文件:Array=new Array();
for(变量i:int=0;i0)删除所有声音();
加载文件(文件);
}
}
//处理“浏览”对话框发送的文件选择事件。
私有函数onFileSelect(事件:FileListEvent):void
{
加载文件(event.files);
}
//处理“浏览”对话框发送的文件夹选择事件。
directoryselect的私有函数(事件:event):void
{
var目录:File=event.target作为文件;
**加载文件(directory.getDirectoryListing())**
}
//将一批文件加载到播放列表中。
私有函数loadFiles(文件:数组):void
{
var文件:文件;
//计算所选文件的数量。仅接受扩展名为.mp3的文件。
selectedFileCount=0;
对于(变量i:uint=0;i<mx:DataGrid x="6"
y="7"
width="388"
height="310"
id="dgPlaylist"
keyDown="onKeyDown(event)"
dragMoveEnabled="true"
doubleClickEnabled="true"
dragEnabled="true"
dropEnabled="true"
dragComplete="onPlaylistDragDrop(event)"
itemDoubleClick="onItemDoubleClick(event)">
<mx:columns>
<mx:DataGridColumn width="168" headerText="Title" dataField="title" />
<mx:DataGridColumn width="160" headerText="Album" dataField="album"/>
<mx:DataGridColumn width="60" headerText="Duration" dataField="duration" textAlign="right" itemRenderer="components.DurationFormatter"/>
</mx:columns>
</mx:DataGrid>
var arrayCollection:ArrayCollection;
arrayCollection.addItem( new Object() );