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03-04 20:06:21.516 2822-2822/com.xjh.ibook E/AndroidRuntime: FATAL EXCEPTION: main
                                                             Process: com.xjh.ibook, PID: 2822
                                                             java.lang.NullPointerException
                                                                 at android.support.v7.widget.RecyclerView.onInterceptTouchEvent(RecyclerView.java:1636)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1859)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
                                                                 at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1917)
                                                                 at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2068)
                                                                 at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1515)
                                                                 at android.app.Activity.dispatchTouchEvent(Activity.java:2458)
                                                                 at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59)
                                                                 at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2016)
                                                                 at android.view.View.dispatchPointerEvent(View.java:7886)
                                                                 at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:3978)
                                                                 at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3857)
                                                                 at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3423)
                                                                 at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3473)
                                                                 at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3442)
                                                                 at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3549)
                                                                 at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3450)
                                                                 at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3606)
                                                                 at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3423)
                                                                 at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3473)
                                                                 at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3442)
                                                                 at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3450)
                                                                 at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3423)
                                                                 at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5626)
                                                                 at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5606)
                                                                 at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5577)
                                                                 at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5706)
                                                                 at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
                                                                 at android.os.MessageQueue.nativePollOnce(Native Method)
                                                                 at android.os.MessageQueue.next(MessageQueue.java:138)
                                                                 at android.os.Looper.loop(Looper.java:123)
                                                                 at android.app.ActivityThread.main(ActivityThread.java:5045)
                                                                 at java.lang.reflect.Method.invokeNative(Native Method)
                                                                 at java.lang.reflect.Method.invoke(Method.java:515)
                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
                                                                 at dalvik.system.NativeStart.main(Native Method)