我正在尝试使用 Flex 库和 FlashDevelop IDE 在 ActionScript 3 中编写程序。该程序需要在舞台上绘制五个空白方块，单击其中任何一个方块将独立呈现一个独特的图案（由几何图元组成），以代替该方块。再次单击这些图案会将它们切换回空白方块。
我决定将这种行为抽象为一个用户定义的类，它是 的扩展Sprite，称为PatternTile. 但是，我收到一个程序错误，PatternTile尽管已将其添加到舞台（由事件处理程序确认），但它本身不可见。默认情况下，对象应在中央舞台渲染，并且根据参数，矩形周围至少应有黑色轮廓。单击时，对象应该通过清除和重新指定图形属性来重绘自己。
构造函数有一个参数可以切换这些属性。现在它们都是等价的。
下面是PatternTile类的代码：
package
{
/**
* ...
* @author ...
*/
import flash.display.Shape;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.display.Stage;
public class PatternTile extends Sprite
{
// OBJECTIVE: Generalize a tile object that can be drawn several times independently and change pattern when clicked.
// DECLARE+INSTANCE VARS
private var tileFlip : Boolean = new Boolean( true ) ; // tileFlip - switch for tracking state of shape when clicked on
// PatternTile, for the sake of simplicity, will include all its potential shapes in its constructor.
private var patternCode : int = new int( ); // Stores pattern classification to switch what the pattern for this tile is.
// CONSTRUCTOR
public function PatternTile( xBase:int, yBase:int, xTrans:int , yTrans:int , patternType:int ):void
{
/* ARGUMENTS:
* xBase - reference point for translations on the X axis.
* yBase - reference point for translations on the Y axis.
* xTrans:int - integer representing displacement of pixels from center on X axis.
* yTrans:int - integer representing displacement of pixels from center on Y axis.
* patternType:int - sets code for pattern
*/
patternCode = patternType
x = xBase + xTrans ; // x - new X position
y = yBase + yTrans ; // y - new Y position
// Assign Parametres to blankTile
this.graphics.lineStyle( 5, 0x000000, 1)
this.graphics.beginFill( 0xFFFFFF, 1 );
this.graphics.drawRect( x , y , 200 , 200 );
this.graphics.endFill( );
// EVENT LISTENERS - Clicking on the Sprite
addEventListener( MouseEvent.CLICK , mouseClickHandler ); // Will this generalize to handling clicks on both pattern types (tile, altObject?);
addEventListener( Event.ADDED_TO_STAGE, addedToStage ); // Created event handler for debugging purposes.
}
// Mouse Click Function
public function mouseClickHandler(event:Event):void
{
if (tileFlip) {
this.graphics.clear(); // clear previous properties
switch (patternCode) {
// Because I know there are only five cases, I can include all of them within the object.
case 0: // Pattern 0
// Colour Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
// Draw shape primitives here
this.graphics.drawCircle( x, y, 50 ); // PLACEHOLDER
this.graphics.endFill( );
// trace("you are here")
break;
case 1: // Pattern 1
// Colour Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
// Draw shape primitives here
this.graphics.drawCircle( x, y, 50 ); // PLACEHOLDER
this.graphics.endFill( );
break;
case 2: // Pattern 2
// Colour Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
// Draw shape primitives here
this.graphics.drawCircle( x, y, 50 ); // PLACEHOLDER
this.graphics.endFill( );
break;
case 3: // Pattern 3
// Colour Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
// Draw shape primitives here
this.graphics.drawCircle( x, y, 50 ); // PLACEHOLDER
this.graphics.endFill( );
break;
case 4: // Pattern 4
// Colour Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
// Draw shape primitives here
this.graphics.drawCircle( x, y, 50 ); // PLACEHOLDER
this.graphics.endFill( );
break;
}
tileFlip = false; // prime alternate state to be checked on next click
} else {
this.graphics.clear(); // clear previous properties
// Blank Tile Properties
this.graphics.lineStyle( 1, 0x000000, 1 );
this.graphics.beginFill(0xFFFFFF, 1);
this.graphics.drawRect( x , y , 100 , 100 );
this.graphics.endFill( );
tileFlip = true; // prime alternate state to be checked on next click
}
}
public function addedToStage(e:Event):void
{
trace("Added PatternTile to stage");
}
}
}
下面是Main课程：
package
{
import flash.display.Shape;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
// User-Defined Classes
import PatternTile
/**
* ...
* @author kbruskie
*/
public class Main extends Sprite
{
// Center Stage, called throughout program.
private var xCenter : int = new int( stage.stageWidth / 2 );
private var yCenter : int = new int( stage.stageHeight / 2 );
// Tiles
private var tile1 : PatternTile ;
/*
private var tile2 : PatternTile = new PatternTile( 0, 0, 0 );
private var tile3 : PatternTile = new PatternTile( 0, 0, 0 );
private var tile4 : PatternTile = new PatternTile( 0, 0, 0 );
private var tile5 : PatternTile = new PatternTile( 0, 0, 0 );
*/
public function Main():void
{
trace(xCenter) // prints center of stage on X axis - working
trace(yCenter) // prints center of stage on Y axis - working
tile1 = new PatternTile( xCenter, yCenter, 200, -200, 1 ) // draws single clickable tile in the middle of the stage. Not yet added to stage.
// instances the object but it isn't visibly drawn. What's going on?
stage.addChild(tile1) // Finally - all the properties are set, and this object is ready for showbiz. Add to stage.
}
}
}
我不明白发生了什么，我对我的理论没有信心。任何人都可以帮忙吗？