作为练习，我尝试扩展 ImageButton 以添加一些我认为有用的功能。其中一个尤其是卓尔阴影。我已经用这个撞到了众所周知的墙。
在我看来，扩展 BitmapDrawable 的类是必要的。此类包含一个 Paint 对象，用于将位图绘制到屏幕上。如果我有权访问这个 Paint 对象...我所要做的就是调用它的 setShadowLayer() 方法...但是，唉，它是 私人的。有一个 public 方法 getPaint() 将返回绘制对象，但对其进行任何修改都是无用的，除非有相应的 setPaint()< /代码> 方法。 （没有。）
目前，我的思考过程如下所示...
- 创建扩展 BitmapDrawable 的类
ShadowBitmapDrawable
- 在此类中，以某种方式更改
BitmapDrawable 的 Paint 对象与 Paint 的 setShadowLayer() 方法。
- 在我的自定义
ImageButton 类中，调用 setImageDrawable(Drawable d)，并将其传递给我的 ShadowBitmapDrawable 对象。
第 2 步是路障。我可以做什么来更改 BitmapDrawable 的 Paint 对象？请注意，我添加我的思维过程只是为了表明我在这个问题中所处的位置。我愿意接受其他建议。
以下是一些参考：
PS我有一种不好的预感，我已经知道我会得到的答案，但我不会喜欢它。我想无论如何都会发布这个问题并希望得到最好的结果。
As an exercise, I am trying to extend ImageButton to add some features I think would be useful. One, in particular, is a drow shadow. I've hit the proverbial wall with this one.
It seems to me, that a class extending BitmapDrawable is necessary. This class contains a Paint object used to draw the bitmap to the screen. If I had access to this Paint object... all I would have to do is call it's setShadowLayer() method... but, alas, it is private. There is a public method, getPaint() that will return the paint object, but any modifications to it would be useless unless there were a corresponding setPaint() method. (There isn't.)
Currently, my thought process looks something like the following...
- Create class
ShadowBitmapDrawable which extends BitmapDrawable
- Within this class, somehow alter the
BitmapDrawable's Paint object with Paint's setShadowLayer() method.
- In my custom
ImageButton class, call setImageDrawable(Drawable d), and pass it my ShadowBitmapDrawable object.
Step 2 is the road block. What can I do to change BitmapDrawable's Paint object? Note that I added my thought process only as an indicator of where I am in this problem. I am open to other suggestions.
Here are some references:
P.S. I have a bad feeling I already know the answer I'm going to get, and I'm not going to like it. Thought I'd post the question anyways and hope for the best.
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将 BitmapDrawable 克隆到您的项目中，将其重构到您自己的包中，使数据成员受保护（或提供受保护的 setter 或其他东西），使用修改后的
BitmapDrawable，并测试它的效果。Clone
BitmapDrawableinto your project, refactor it into your own package, make the data memberprotected(or provide aprotectedsetter or something), use your modifiedBitmapDrawable, and test the heck out of it.