求教关于ratingbar

我复制SDK文档中的例子在模拟器中运行，为什么点击ratingbar的时候会跳出错误11-06 12:05:34.477: E/AndroidRuntime(17236): FATAL EXCEPTION: main
11-06 12:05:34.477: E/AndroidRuntime(17236): java.lang.NullPointerException
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.widget.AbsSeekBar.onTouchEvent(AbsSeekBar.java:338)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.View.dispatchTouchEvent(View.java:5462)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1680)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1680)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1680)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1680)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1882)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1361)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.app.Activity.dispatchTouchEvent(Activity.java:2364)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1830)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.View.dispatchPointerEvent(View.java:5638)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2827)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2406)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.os.Looper.loop(Looper.java:137)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at android.app.ActivityThread.main(ActivityThread.java:4340)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at java.lang.reflect.Method.invokeNative(Native Method)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at java.lang.reflect.Method.invoke(Method.java:511)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
11-06 12:05:34.477: E/AndroidRuntime(17236):  at dalvik.system.NativeStart.main(Native Method)
另外关于res/xml和res/anim下的xml文件没有提示功能，需要自己添加dtd文件还是需要在哪里设置？？？？