AS3 CookBook学习整理(二)

1. 我要改变影片的对齐方式

使用stage.align属性

stage.align的值是flash.display.StageAlign类的一个枚举。其值如下：

Value	Vertical Alignment	Horizontal
StageAlign.TOP	Top	Center
StageAlign.BOTTOM	Bottom	Center
StageAlign.LEFT	Center	Left
StageAlign.RIGHT	Center	Right
StageAlign.TOP_LEFT	Top	Left
StageAlign.TOP_RIGHT	Top	Right
StageAlign.BOTTOM_LEFT	Bottom	Left
StageAlign.BOTTOM_RIGHT	Bottom	Right

package
{
    import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    public class Sample1105 extends Sprite
    {
        public function Sample1105()
        {
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align = StageAlign.TOP_RIGHT;
            
            this.graphics.beginFill(0xFF0000);
            this.graphics.drawRect(10,10,stage.stageWidth,stage.stageHeight);
            this.graphics.endFill();            
        }
    }
}

2. 确定客户端是否能播放音频

使用flash.system.Capabilities的hasAudio判断是否支持音频，hasMP3判断是否能播放MP3

if(flash.system.Capabilities.hasAudio && flash.system.Capabilities.hasMP3)
{
}
else
{
}

3. 提示用户改变播放器设置

使用flash.system.Security.showSettings()方法打开用户的Flash播放器设置对话框窗口

该方法接受一个flash.system.SecurityPanel枚举作为参数。对应功能如下：

SecurityPanel.DEFAULT 默认面板

SecurityPanel.CAMERA 摄像头面板

SecurityPanel.LOCAL_STORAGE 本地存储面板

SecurityPanel.MICROPHONE 话筒面板

SecurityPanel.PRIVACY 安全控制面板

SecurityPanel.SETTINGS_MANAGER 管理面板会打开浏览器进行更多设置

package {
    import flash.display.Sprite;
    import flash.system.Security;
    import flash.system.SecurityPanel;
    public class Sample1117 extends Sprite
    {
        public function Sample1117()
        {
            flash.system.Security.showSettings(flash.system.SecurityPanel.DEFAULT);
        }
    }
}

4. 对数值进行四舍五入或取近似值

用Math.round()进行四舍五入，Math.floor()和Math.ceil()进行上下近似值。NumberUtilities.round()方法可自定义取值

package {
    import ascb.util.NumberUtilities;
    
    import flash.display.Sprite;
    public class Sample1117 extends Sprite
    {
        public function Sample1117()
        {
            trace(Math.round(234.56)); //235 
            trace(Math.floor(234.56)); //234; 
            trace(Math.ceil(234.56));  //235; 
            
            trace(Math.round(123.456*100)/100);//123.46; 
           //也有一种写法，可读性比上面好 
            trace(Math.round(123.456/0.1)*0.1);//123.5; 
           //第三方函数的方法，实现机制其实和上面一样 
            trace(NumberUtilities.round(123.456,0.1)); //123.5 
            trace(NumberUtilities.round(123.456,6));   //126; 
            
        }
    }
}

5. 对数字和字符串进行格式化

用NumberFormat对象的format()与currencyFormat()方法。由于是第三方类库，测试过程中发现有些不完善。自己写了一个格式化货币的方法

package {
    import flash.display.Sprite;
    
    public class Sample1118 extends Sprite
    {
        public function Sample1118()
        {
            var money:Number = 26591234569.5678;
            trace(formatString(money));//26,591,234,569.57 
            var i:int = 1234;
            trace(formatString(i));//1,234.00 
            trace(formatString("fox"));
        }
        private function formatString(obj:Object):String
        {
            if(obj  is  int||obj  is  uint||obj  is  Number)
            {
                var money:Number = obj  as  Number;
                var str:String = (Math.round(money/0.01) * 0.01).toString();
                var _index:int = str.indexOf(".");
                var cursor:int = 0;
                if(_index>-1)
                {
                    cursor = _index;
                    str = str.substring(0,_index + 3);
                    while(str.length < _index+3)
                    {
                        str = str + "0";
                    }           
                }
                else
                {
                    cursor = str.length;
                    str = str+".00";
                }
                var arrStr:Array = new Array();
                while(cursor-3>=0)
                {
                    arrStr.push(str.substr(cursor-3,3));
                    cursor = cursor-3;
                }
                if(cursor>0)
                {
                    arrStr.push(str.substr(0,cursor));
                }
                arrStr.reverse();
                return arrStr.join(',') + str.substr(str.indexOf("."));
            }
            else
            {
                return obj.toString();
            }
        }   
    }
}

6. 生成随机数(猜硬币)

用NumberUtilities.random(0,1)方法产生随机数

package {
    import ascb.util.NumberUtilities;
    
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.text.TextField;
    
    public class Sample1118 extends Sprite
    {   
        private var label:TextField;
        public function Sample1118()
        {
            label = new TextField();
            label.background = true;
            label.backgroundColor = 0xFF0000;
            label.textColor = 0xF7FCFF;
            label.autoSize = "left";
            this.addChild(label);
            var sprite:Sprite = new Sprite();
            sprite.graphics.beginFill(0xFFFF00);
            sprite.graphics.drawCircle(100,100,50);
            sprite.graphics.endFill();
            sprite.addEventListener(MouseEvent.CLICK,OnClick);
            this.addChild(sprite);
        }
        private function OnClick(event:MouseEvent):void
        {
            if(NumberUtilities.random(0,1)==0)
            {
                label.text = "正面";
            }
            else
            {
                label.text = "背面";
            }
        }
    }
}

7. 生成随机数(骰子)

用NumberUtilities.random(1,6)方法产生随机数

package {
    import ascb.util.NumberUtilities;
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    public class Sample1119 extends Sprite
    {   
        private var sprite:Sprite;
        public function Sample1119()
        {
            sprite = new Sprite();
            this.addChild(sprite);
            sprite.addEventListener(MouseEvent.CLICK,OnClick);
            OnClick(null); //第一次显示出来 
        }
        
        private function OnClick(event:MouseEvent):void
        {
            sprite.graphics.clear();
            sprite.graphics.beginFill(0xFFFFFF);
            sprite.graphics.drawRect(0,0,50,50);
            sprite.graphics.endFill();
            var randNum:int = NumberUtilities.random(1,6);
            sprite.graphics.beginFill(0x000000);
            if(randNum==1)
            {       
                sprite.graphics.drawCircle(25,25,6);
            }
            else if(randNum!=2)
            {
                sprite.graphics.drawCircle(8,8,6);
                sprite.graphics.drawCircle(42,42,6);
            }
            if(randNum==3||randNum==5)
            {
                sprite.graphics.drawCircle(25,25,6);                
            }
            if(randNum==4||randNum==5||randNum==6)
            {
                sprite.graphics.drawCircle(42,8,6); 
                sprite.graphics.drawCircle(8,42,6);
            }
            if(randNum==2)
            {
                sprite.graphics.drawCircle(25,8,6);
                sprite.graphics.drawCircle(25,42,6);            
            }
            if(randNum==6)
            {
                sprite.graphics.drawCircle(8,25,6);
                sprite.graphics.drawCircle(42,25,6);
            }
            sprite.graphics.endFill();
        }
    }
}

8. 生成唯一随机数(基于毫秒)

调用NumberUtilities.getUnique()得到当前时间(精确到毫秒)的唯一数字

package {
    import ascb.util.NumberUtilities;
    import flash.display.Sprite;
    public class Sample1119 extends Sprite
    {   
        public function Sample1119()
        {
            for(var i:uint=0;i<10;i++)
            {
                trace(NumberUtilities.getUnique());
            }
        }
    }
}

9. 计算两点之间的距离

根据勾股定理，使用Math.pow()和Math.sqrt()联合计算

package {   
    import flash.display.Sprite;
    import flash.geom.Point;
    public class Sample1119 extends Sprite
    {   
        public function Sample1119()
        {
            var p1:Point = new Point(10,20);
            var p2:Point = new Point(100,200);
            var x:int = p1.x - p2.x;
            var y:int = p1.y = p2.y;
            var length:Number = Math.sqrt(Math.pow(x,2)+Math.pow(y,2));
            trace(length);
        }
    }
}

10. DisplayObject类结构图

flash.display包中包含Flash Player用于构建可视显示内容的核心类。DisplayObject类是可放在显示列表中的所有对象的基类