我已经试过这样：

r = Resources.getSystem().getIdentifier("ball_red","drawable","com.Juggle2");
Log.i("FindBall","R = "+r);

和这样的：

r = Resources.getSystem().getIdentifier("com.Juggle2:drawable/ball_red", null, null);

不过，R最终总是为零。

But 'r' always ends up as zero.

我打电话这条线从一个辅助类，这不是一个活动，并没有延伸什么里面，所以无法简单地调用 getResources（），但我可以从我的 SurfaceView 通过。

I'm calling this line from inside a helper class that's not an Activity and doesn't extend anything, so I can't simply call getResources(), but I can pass it from my SurfaceView.

最后，我想替换ball_red有一个变量，但第一件事情第一。这是行不通的。

Eventually, I want to replace "ball_red" with a variable, but first thing's first. This isn't working.

com.Juggle2 确实是我包的名字。 绘制是 RES 文件夹，它是在，而且，该文件的名称确实是 ball_red 。

com.Juggle2 is indeed my package name. drawable is the res folder that it's in, and, the name of the file is indeed ball_red.

R.java说：

        public static final int ball_red=0x7f020027;

所以我不知道为什么它不工作。

So I'm not sure why it isn't working.

所以，我不能使用的资源，我必须通过一个背景，而我这样做是这样的： 里面的位置：

So I can't use Resources, I must pass a context, and I'm doing that this way: Inside here:

class Collection extends SurfaceView implements SurfaceHolder.Callback {

我做我的类的新实例，并传递给它的getContext（）作为一个参数。

推荐答案

既然你是一个活动里面就足以写

Since you are inside of an activity it is enough to write

int resId=YourActivity.this.getResources().getIdentifier("ball_red", "drawable", YourActivity.this.getPackageName());

或者，如果你不从内部类调用它

or if you're not calling it from an inner class

int resourceID = getResources().getIdentifier("ball_red", "drawable", getPackageName());

注意

getIdentifier() Returns 0 if no such resource was found. (0 is not a valid resource ID.)

查看

也检查你的R.java是否有绘制名为 ball_red

Check also in your R.java whether there is a drawable with the name ball_red

例如：

public static final class drawable {
        public static final int ball_red=0x7f020000;
 }

修改 如果你没有在任何活动，那么你必须已经过时了一个环境，而不是资源参数然后执行

EDIT If you're not in any activity then you must passe a context instead of resources as parameter then do this

int resId=context.getResources().getIdentifier("ball_red", "drawable", context.getPackageName());