标签: instance

有多个MovieClip将动态放置在舞台上.这些MovieClip被编码为按钮.我想弄清楚 - 当用户点击MovieClip时...找出用户点击的flash阶段上的哪个对象.

内部函数toggleClick我把trace语句:

trace("movieClip Instance Name = " + e.target.name);

在OUTPUT窗口中:

movieClip Instance Name = instance5 
movieClip Instance Name = instance12 
movieClip Instance Name = instance5 
movieClip Instance Name = instance32 
movieClip Instance Name = instance5 
movieClip Instance Name = instance59 

这似乎不是获取被点击的MovieClip的名称的方法.

getChildByName()是这样做的吗？如果是这样,任何想法如何使用getChildByName()来获取被点击的MovieClip的名称？

    Public Sub New()
        If GridElement.typeList(getId(), getLayer()) Is Nothing Then
            GridElement.typeList(getid(),getlayer()) = GetType(me)
        End If
    End Sub

看看上面的代码片段.在第三行,我试图将多维数组设置为当前类的类型.我怎样才能获得我目前所在班级的类型？

我正在使用VB.net所以所有.net示例都可以接受.

我想创建一个带有变量的实例,指定下面的一些特征,这会给你一个错误.无论如何在scala中这样做？

var traitRefer = classOf[SomeTrait]
var a = new SomeClass() with traitRefer

我在Python中遇到了一个我无法相信的问题.请参阅以下代码:

class Container(object):
    array = []

    def __init__(self):
        print self.array

for i in range(0, 5):
    container = Container()
    container.array.append('Test')
print 'Last Container:', container.array

输出是:

[]
['Test']
['Test', 'Test']
['Test', 'Test', 'Test']
['Test', 'Test', 'Test', 'Test']
Last Container: ['Test', 'Test', 'Test', 'Test', 'Test']

我认为Container该类在实例化时使用顶部的值进行初始化.为什么不是这样？

谢谢!

我是Objective C的新手,我对这个概念感到困惑.

以下方法应该创建作为参数传递的类的实例并编辑实例的变量.

- (void) createObject:(Class)objecttype atPoint: (CGPoint)position {

    if ([objecttype isSubclassOfClass:[GameObject class]]){

        id theobject = [[objecttype alloc] init];

        theobject.x = position.x; //error
        theobject.y = position.y; //error
    }
}

我收到上面显示的错误消息: Property 'x' not found on object of type '__strong id'

看起来它应该很简单,但我不明白什么是错的.

I have two classes, A and B.

B contains the instances of A. I want to return instance of A from B by its name:

class A
{
    public String name;

    public A (String name)
    {
        this.name = name;
    }
}

class B
{
    public A a1;
    public A a2;
    public A a3;

    public B ()
    {
        this.a1 = new A ("a1");
        this.a2 = new A ("a2");
        this.a3 = new A ("a3");
    }

    public A get_A_byName (String name)
    {
        // …

我已经尝试查看有关此问题的帖子,但我的代码中仍然遇到此错误的问题.所以在第四行中,我创建了一个名为SongDatabase访问SongDatabase该类的实例变量.但是当我到达线SongDatabase.addNewSong();下时case 1,我得到一个java.lang.NullPointerException:null错误.

接口类:

public class Interface 
{
    Scanner console = new Scanner(System.in);
    private SongDatabase SongDatabase;

    public static void main(String[] args) {
        Interface intFace = new Interface();
        intFace.run();
    }

    private void run() {
        switch (userInput) {
        case 1: 
            SongDatabase.addNewSong();
            break;
        case 2:
            SongDatabase.removeSong();
            break;
        case 3:
            SongDatabase.sortSongs();
            break;
        default:
            System.out.println("Please enter a valid number.");
            break;

    }
}

SongDatabase类:

public class SongDatabase {
    Scanner console = new Scanner(System.in);  
    private Song song1, song2, song3, song4; …

我在Haskell中有以下代码:

module Shape where
type Height = Float
type Width  = Float
type Radius = Float
data Rectangle  = Rectangle Height Width 
data Circle = Circle Radius

class (Eq a, Show a) => Shape a where
   area :: a -> Float
   perimeter :: a -> Float

instance Shape Rectangle where
    area (Rectangle h w) = h * w
    perimeter (Rectangle h w) = h*2 + w*2
    show (Rectangle h w) = "rectangle "  ++ (show h) ++ " " ++ …

我正在研究涉及统一的问题,使用用户定义的类型Subst a.问题是:

"定义一个类型类Unifiable,它指定一个函数unify :: a - > a - > Maybe(Subst a)必须为这个类中的任何一个类型定义.一个类型a只能在Unifiable类中,如果它已经是在Eq和Substitutable类中,这应该在你的定义中表示."

到目前为止,我已经定义了Substitutable和Unifiable:

class Substitutable a where
subst :: Subst a -> a -> a

class Unifiable a where
unify :: a -> a -> Maybe (Subst a)

但是,我不确定如何将类型a指定为Unifiable类,只有它已经在Eq和Substitutable类中.

我不是在寻找这个特定问题的答案,但总的来说,如果指定一个类型只能在一个类中,如果它已经存在于其他类中,我该怎么办？

谢谢.

1. 我试图回答这个问题:"给定代数数据类型

   data Maybe a = Nothing | Just a
   

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   选择正确的实例声明,显示类型构造函数Maybe是一个Monad."(取自这里:"DelftX:FP101x函数式编程简介".

2. 我试图解决的方法是依次编译每个潜在的答案,例如,这个:

   instance Monad Maybe where
              return x = Just x
              Nothing >>= _ = Nothing
              (Just x ) >>= f = f x
   

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3. 我无法编译它,因为它已在前奏中定义.

   HwEx9.hs:16:10: error:
       Duplicate instance declarations:
         instance Monad Maybe -- Defined at HwEx9.hs:16:10
         instance Monad Maybe -- Defined in `GHC.Base'
   

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我的问题是:我怎么编译它？