小编Zac*_*ers的帖子

我正在研究的Android应用程序中有一个非常不明显的错误.我有一个片段,它依次包含一个由FragmentStatePagerAdapter支持的ViewPager.寻呼机包含两个片段.

每当我尝试添加一个PageTransformer(使用Android开发者网站上的那些:http://developer.android.com/training/animation/screen-slide.html),一切正常,直到我试图离开片段包含viewpager(backpress或regular).我得到的错误如下.我无法真正追踪导致它的原因x_x.底部的寻呼机结构的代码片段.

Process: edu.utcs.android, PID: 11728
    java.lang.NullPointerException
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2946)
            at android.view.View.draw(View.java:14476)
            at android.support.v4.view.ViewPager.draw(ViewPager.java:2171)
            at android.view.View.getDisplayList(View.java:13370)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at android.view.ViewGroup.drawChild(ViewGroup.java:3103)
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2940)
            at android.view.View.draw(View.java:14476)
            at android.widget.FrameLayout.draw(FrameLayout.java:472)
            at android.view.View.getDisplayList(View.java:13370)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at android.view.ViewGroup.drawChild(ViewGroup.java:3103)
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2940)
            at android.view.View.getDisplayList(View.java:13365)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at android.view.ViewGroup.drawChild(ViewGroup.java:3103)
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2959)
            at android.view.View.getDisplayList(View.java:13365)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at android.view.ViewGroup.drawChild(ViewGroup.java:3103)
            at android.support.v4.widget.DrawerLayout.drawChild(DrawerLayout.java:870)
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2940)
            at android.view.View.getDisplayList(View.java:13365)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at android.view.ViewGroup.drawChild(ViewGroup.java:3103)
            at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2940)
            at android.view.View.getDisplayList(View.java:13365)
            at android.view.View.getDisplayList(View.java:13412)
            at android.view.View.draw(View.java:14190)
            at …