flash – ActionScript属性 – 公共Getter,受保护的Setter

我有以下代码：

public class Mob extends Sprite {
    // snip

    private var _health:Number; // tried making this protected,didn't work
    public function get health():Number { return _health; }
    protected function set health(value:Number):void {
        _health = value;
    }

    // snip

    public function takeDamage(amount:Number,type:DamageType,... additionalAmountAndTypePairs):void {
        var dmg:Number = 0;
        // snip
        var h:Number = this.health; // 1178: Attempted access of inaccessible property health through a reference with static type components.mobs:Mob.
        this.health = h - dmg; // 1059: Property is read-only.
    }
}

我确实有这个.健康 – = dmg;但我把它拆分出来以获得有关编译器错误的更多细节.

我不明白该属性如何在同一个类中被认为是只读的.我也不明白它是如何无法进入的.

如果我将支持字段,getter和setter全部保护起来,它会编译,但这不是我想要的结果;我需要外在可读的健康.