[英]ListViewAnimation insert() NullPointerException on notifyDataSetChanged()
我正在使用ListViewAnimation库,并尝试为ListView做添加项动画。
为了实现这种动画,他们的文档说我应该这样做:
要使用此功能,只需让您的适配器实现Insertable,然后在DynamicListView上调用insert方法之一:
MyInsertableAdapter myAdapter = new MyInsertableAdapter(); // MyInsertableAdapter implements Insertable
mDynamicListView.setAdapter(myAdapter);
mDynamicListView.insert(0, myItem); // myItem is of the type the adapter represents.
所以这就是我所做的:
我将Listview设置为DynamicListView(我正在使用ButterKnife )并将其设置为使用我的适配器
@InjectView(R.id.flow_list) DynamicListView mFlowList; mFlowListAdapter = new FlowListAdapter(getActivity(), mItems); mFlowList.setAdapter(mFlowListAdapter);
使我的适配器实现“ Insertable”接口并覆盖其抽象方法:
@Override public void add(int i, @NonNull Object o) { Item newItem = (Item)o; mList.add(Item); notifyDataSetChanged(); }
在我的ListView上调用insert()
@OnClick(R.id.done) void addItem() { ... mFlowList.insert(0,item); }
但是,当我运行我的应用程序并单击触发ListView的insert()的完成按钮时,我得到了NullPointerException:
09-15 11:51:41.046 14660-14660/com.jezer.MyApp E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at com.nhaarman.listviewanimations.itemmanipulation.animateaddition.AnimateAdditionAdapter$HeightUpdater.onAnimationUpdate(AnimateAdditionAdapter.java:352)
at com.nineoldandroids.animation.ValueAnimator.animateValue(ValueAnimator.java:1178)
at com.nineoldandroids.animation.ValueAnimator.animationFrame(ValueAnimator.java:1139)
at com.nineoldandroids.animation.ValueAnimator.setCurrentPlayTime(ValueAnimator.java:545)
at com.nineoldandroids.animation.ValueAnimator.start(ValueAnimator.java:928)
at com.nineoldandroids.animation.ValueAnimator.start(ValueAnimator.java:951)
at com.nineoldandroids.animation.AnimatorSet.start(AnimatorSet.java:502)
at com.nineoldandroids.animation.AnimatorSet.start(AnimatorSet.java:502)
at com.nhaarman.listviewanimations.itemmanipulation.animateaddition.AnimateAdditionAdapter.getView(AnimateAdditionAdapter.java:318)
at android.widget.AbsListView.obtainView(AbsListView.java:2232)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1253)
at android.widget.ListView.onMeasure(ListView.java:1162)
at android.view.View.measure(View.java:15775)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:681)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461)
at android.view.View.measure(View.java:15775)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15775)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15775)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:850)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15775)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2193)
at android.view.View.measure(View.java:15775)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2212)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1291)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1486)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1181)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4942)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:776)
at android.view.Choreographer.doCallbacks(Choreographer.java:579)
at android.view.Choreographer.doFrame(Choreographer.java:548)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:762)
at android.os.Handler.handleCallback(Handler.java:800)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5391)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
当我在add()方法上注释出notifyDataSetChanged()时,没有得到此异常。 但这是我知道刷新列表视图并希望看到附加动画的唯一方法。
您也许正在这样做: convertView = inflater.inflate(R.layout.cell, null);
代替这个? convertView = inflater.inflate(R.layout.page_cell, parent, false);
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