Android 2.3下重写PopupWindow的NullPointerException问题

重写PopupWindow后，自定义PopupWindow的样式。重写了构造函数，发现4.0以上木有问题，2.3一下会有崩溃问题，如下：

03-21 11:23:36.149: E/AndroidRuntime(13738): java.lang.NullPointerException

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.widget.PopupWindow.setContentView(PopupWindow.java:384)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.widget.PopupWindow.<init>(PopupWindow.java:286)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.widget.PopupWindow.<init>(PopupWindow.java:266)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.widget.PopupWindow.<init>(PopupWindow.java:223)

03-21 11:23:36.149: E/AndroidRuntime(13738): at com.sdtv.sdsjt.views.PaikeTipPopwindow.<init>(PaikeTipPopwindow.java:25)

03-21 11:23:36.149: E/AndroidRuntime(13738): at com.sdtv.sdsjt.paike.HDVoiceRecordActivity$2.onClick(HDVoiceRecordActivity.java:151)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.view.View.performClick(View.java:2486)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.view.View$PerformClick.run(View.java:9130)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.os.Handler.handleCallback(Handler.java:587)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.os.Handler.dispatchMessage(Handler.java:92)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.os.Looper.loop(Looper.java:130)

03-21 11:23:36.149: E/AndroidRuntime(13738): at android.app.ActivityThread.main(ActivityThread.java:3703)

03-21 11:23:36.149: E/AndroidRuntime(13738): at java.lang.reflect.Method.invokeNative(Native Method)

03-21 11:23:36.149: E/AndroidRuntime(13738): at java.lang.reflect.Method.invoke(Method.java:507)

03-21 11:23:36.149: E/AndroidRuntime(13738): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)

03-21 11:23:36.149: E/AndroidRuntime(13738): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:624)

03-21 11:23:36.149: E/AndroidRuntime(13738): at dalvik.system.NativeStart.main(Native Method)