我真的不知道问题到底要问什么。所以我将在这里解释一切：
我正在使用桌面AIR数据库应用程序我有一个名为“数据库屏幕”的类，它链接到一个影片剪辑：
package {
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.display.InteractiveObject;
import flash.filesystem.File;
import flash.filesystem.FileStream;
import flash.filesystem.FileMode;
import flash.utils.Timer;
import flash.events.TimerEvent;
import flash.text.TextField;
public class DatabaseScreen extends MovieClip {
private var allButtons:Array;
private var codeSelected:Boolean;
private var nameSelected:Boolean;
private var xmlDatabase:XML;
private var dbFile:File;
public var xmlList:XMLList;
private var totalProducts:uint;
private var totalItems:uint = 0;
private var productExists:Boolean;
private var productId:Number;
private var XMLReader:xmlReader;
public function DatabaseScreen() {
allButtons = [searchPanel.search_btn, addNewPanel.addNew_btn, dbStatsPanel.xls_btn, searchPanel.code_radio, searchPanel.name_radio];
init();
}
private function init():void
{
XMLReader = new xmlReader();
//adding event listeners..
for(var i:int = 0; i<allButtons.length; i++)
{
allButtons[i].addEventListener(MouseEvent.MOUSE_OVER, onOver, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_OUT, onOut, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_DOWN, onDown, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_UP, onUp, false, 0, true);
allButtons[i].addEventListener(MouseEvent.CLICK, onClick, false, 0, true);
allButtons[i].buttonMode = true;
}
//creating a new file for the database
dbFile = File.documentsDirectory.resolvePath("BlackCat/Database.xml");
xmlDatabase = new XML();
getXML();
saveXML();
getTotalItems();
dbStatsPanel.items.text = String(totalItems);
}
private function getXML():void
{
if(dbFile.exists)
{
var stream:FileStream = new FileStream();
stream.open(dbFile, FileMode.READ);
xmlDatabase = new XML(stream.readUTFBytes(stream.bytesAvailable));
stream.close();
xmlList = xmlDatabase.Product;
dbStatsPanel.products.text = xmlList.length();
XMLReader.xmlData = xmlList;
XMLReader.updateXMLList(xmlList);
}
else
{
xmlDatabase = <Products></Products>
}
}
public function getXMlList():XMLList
{
return xmlList;
}
private function getTotalItems():void
{
for(var i:int = 0; i < xmlList.length(); i++)
{
totalItems += uint(xmlList[i].@Qty);
}
}
private function saveXML():void
{
var stream:FileStream = new FileStream();
stream.open(dbFile, FileMode.WRITE);
stream.writeUTFBytes(xmlDatabase.toXMLString());
}
private function onDown(evt:MouseEvent):void
{
evt.target.scaleX = evt.target.scaleY = .8;
}
private function onUp(evt:MouseEvent):void
{
evt.target.scaleX = evt.target.scaleY = 1;
}
private function onOver(evt:MouseEvent):void
{
evt.target.alpha = .5;
}
private function onOut(evt:MouseEvent):void
{
evt.target.alpha = 1;
evt.target.scaleX = evt.target.scaleY = 1;
}
private function onClick(evt:MouseEvent):void
{
switch(evt.target.name)
{
case "code_radio":
codeSelected = true;
nameSelected = false;
searchPanel.code_radio.gotoAndStop(1);
searchPanel.name_radio.gotoAndStop(2);
break;
case "name_radio":
nameSelected = true;
codeSelected = false;
searchPanel.code_radio.gotoAndStop(2);
searchPanel.name_radio.gotoAndStop(1);
break;
case "addNew_btn":
//Checking if the product already exists..
for(var i:int = 0; i < xmlList.length(); i++)
{
if(xmlList[i].@code == addNewPanel.add_code_txt.text)
{
productExists = true;
productId = i;
}
}
if(productExists)
{
var PQty:uint = uint(xmlList[productId].@Qty);
var PQtoAdd:uint = uint(addNewPanel.add_qty_txt.text);
PQty += PQtoAdd;
xmlList[productId].@Qty = String(PQty);
productExists = false;
}
else
{
xmlDatabase.appendChild(<Product code={addNewPanel.add_code_txt.text}
name={addNewPanel.add_name_txt.text} Price={addNewPanel.add_price_txt.text}
Qty={addNewPanel.add_qty_txt.text}></Product>);
}
totalItems += uint(addNewPanel.add_qty_txt.text);
xmlList = xmlDatabase.Product;
dbStatsPanel.products.text = xmlList.length();
dbStatsPanel.items.text = String(totalItems);
XMLReader.updateXMLList(xmlList);
saveXML();
trace(xmlDatabase);
break;
}
}
public function setVisiblity(visibility:Boolean):void
{
switch(visibility)
{
case true:
this.visible = true;
break;
case false:
this.visible = false;
break;
}
}
public function getXMLList():XMLList
{
return xmlList;
}
}
}
我有另一个名为“NewOrder”的类，在这个类中我试图从“DatabaseScreen”类访问xmlList，但我无法这样做。
package {
import flash.display.MovieClip;
import flash.events.MouseEvent;
import com.greensock.TweenMax;
import flash.filesystem.File;
import flash.filesystem.FileStream;
import flash.filesystem.FileMode;
public class NewOrder extends MovieClip {
private var allButtons:Array;
private var shoppingCart:Array;
private var scroller:FlickScroll;
private var db:DatabaseScreen;
private var XMLReader:xmlReader;
public function NewOrder() {
this.visible = false;
init(db);
}
private function init(dbase:DatabaseScreen):void
{
XMLReader = new xmlReader();
trace(XMLReader.xmlData);
scroller = new FlickScroll(masker, container, 84.05, -500);
addChild(scroller);
allButtons = [scan_btn, print_invoice];
shoppingCart = [];
for(var i:int = 0; i < allButtons.length; i++)
{
allButtons[i].addEventListener(MouseEvent.MOUSE_OVER, onOver, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_OUT, onOut, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_DOWN, onDown, false, 0, true);
allButtons[i].addEventListener(MouseEvent.MOUSE_UP, onUp, false, 0, true);
allButtons[i].mouseChildren = false;
allButtons[i].buttonMode = true;
}
}
private function onOver(evt:MouseEvent):void
{
evt.target.alpha = .5;
}
private function onOut(evt:MouseEvent):void
{
evt.target.alpha = 1;
evt.target.scaleX = evt.target.scaleY = 1;
}
private function onDown(evt:MouseEvent):void
{
evt.target.scaleX = evt.target.scaleY = .8;
}
private function onUp(evt:MouseEvent):void
{
evt.target.scaleX = evt.target.scaleY = 1;
if(evt.target.name == "scan_btn")
{
var cartElement:CartElement = new CartElement();
container.addChild(cartElement);
cartElement.x = 0;
cartElement.alpha = 0;
TweenMax.to(cartElement, .4, {alpha:1});
shoppingCart.push(cartElement);
cartElement.id_txt.text = String(shoppingCart.length) + " - ";
if(shoppingCart.length < 2)
{
cartElement.y = container.height - 30;
}
else
{
cartElement.y = container.height + 5;
}
}
}
}
}
还有一个Main类，我处理所有屏幕，例如DatabaseScreen，NewOrder ..这意味着我已将这些添加到Main类的显示列表中。为了从DatabaseScreen访问xmlList，我尝试在NewOrder类中创建一个新实例，但它创建了DatabaseScreen。我还尝试创建另一个名为“xmlReader”的类： 包{
public class xmlReader {
public var xmlData:XMLList;
public function xmlReader() {
}
public function updateXMLList(updatedList:XMLList):void
{
xmlData = updatedList;
}
}
}
在databaseScreen类中，只要我填充xmlList，我就将xmlReader类的xmlData设置为等于databaseScreen类中的xmlList。当我在databaseScreen中跟踪XMLReader.xmlData时，它工作正常。但是当我在NewOrder类中做同样的事情时，我在输出窗口中得到“null”。 我该如何解决这个问题。非常感谢任何帮助。
答案 0 :(得分：1)
您需要将引用传递给Order类才能访问DatabaseScreen类。这样的事情。
var ds = new DatabaseScreen();
var or = new NewOrder(ds)
在NewOrder中，您可以保存参考号。
public class NewOrder {
private var screens:DatabaseScreens;
public function NewOrder(ds:DatabaseScreens) {
screens = ds;
// Now you can call screens.xmlList
}
}