位于DaysAdapter.getView（DaysFragment.java:117）的NPE

直觉上我知道为什么会出现NPE异常，但在这种情况下我找不到原因。也许这只是一天的结束。 我在这条线上得到了NPE

viewHolder.dayCaption.setText(storage.getDayName(i));

我使用此代码记录：

Log.d("MTEST","viewHolder="+viewHolder+"\nviewHolder.dayCaption="+viewHolder.dayCaption+"\nstorage.getDayName(i)="+storage.getDayName(i));

得到这个值：

viewHolder=com.bbc.ddm.fragments.DaysFragment$DaysAdapter$ViewHolder@423df950
viewHolder.dayCaption= android.widget.TextView@423ded08

storage.getDayName(i)=Monday

这满是适配器

 private class DaysAdapter extends BaseAdapter implements AdapterView.OnItemClickListener{

    @Override
    public int getCount() {
        return dayEnabled.length;
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return i;
    }
    private class ViewHolder {
        TextView dayCaption;
        CheckBox dayCheck;
    }
    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder viewHolder;

        if (view == null) {
            view = getActivity().getLayoutInflater().inflate(R.layout.day_list_item, viewGroup, false);
            viewHolder = new ViewHolder();
            viewHolder.dayCaption = (TextView) view.findViewById(R.id.day_caption);
            viewHolder.dayCheck = (CheckBox) view.findViewById(R.id.day_check);                
        } else {
            viewHolder = (ViewHolder) view.getTag();
        }
        storage = Storage.getInstance();
//            Log.d("MTEST","viewHolder="+viewHolder+"\nviewHolder.dayCaption= "+viewHolder.dayCaption+"\nstorage.getDayName(i)="+storage.getDayName(i));
            viewHolder.dayCaption.setText(storage.getDayName(i));
            viewHolder.dayCheck.setTag(i);
            viewHolder.dayCheck.setChecked(dayEnabled[i]);
            viewHolder.dayCheck.setOnCheckedChangeListener(checkedChangeListener);

        return view;
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        activity.showDayTime(i);
    }




}

---

您忘记了使用

setTag（）

在视图中存储视图保持架。在循环视图中，使用

getTag（）

检索的持有者将为空

加

---

在

if（view==null）

块的末尾。

您介意再显示一点代码吗？从你的日志来看，这可能有用。我怀疑问题有点深。我已经添加了适配器。您还可以显示实际的错误日志吗？您是否可以注释掉某些部分，以检查此问题是否仅存在于

viewHolder.daycontrol

或整个

viewHolder

？这不是一个大项目，但也不容易。我在改变碎片，我肯定在某个地方失去了价值。无法在此情况下使用调试

10-01 17:18:19.176: E/AndroidRuntime(4455): FATAL EXCEPTION: main
10-01 17:18:19.176: E/AndroidRuntime(4455): java.lang.NullPointerException
10-01 17:18:19.176: E/AndroidRuntime(4455):     at com.revolage.eyespause.fragments.DaysFragment$DaysAdapter.getView(DaysFragment.java:120)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.AbsListView.obtainView(AbsListView.java:2255)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.ListView.measureHeightOfChildren(ListView.java:1269)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.ListView.onMeasure(ListView.java:1181)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1421)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:698)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:579)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:315)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:315)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:622)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:404)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:315)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:850)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:579)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:315)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2155)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.View.measure(View.java:15323)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1854)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1102)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1275)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4218)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.Choreographer.doCallbacks(Choreographer.java:555)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.Choreographer.doFrame(Choreographer.java:525)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.os.Handler.handleCallback(Handler.java:615)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.os.Handler.dispatchMessage(Handler.java:92)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.os.Looper.loop(Looper.java:137)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at android.app.ActivityThread.main(ActivityThread.java:4744)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at java.lang.reflect.Method.invokeNative(Native Method)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at java.lang.reflect.Method.invoke(Method.java:511)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-01 17:18:19.176: E/AndroidRuntime(4455):     at dalvik.system.NativeStart.main(Native Method)

view.setTag(viewHolder);