带有Listadapter错误的Android片段（无法启动activity ComponentInfo）

我是android应用程序编程的初学者

当我将片段与ListAdapter一起使用时，我遇到了错误

这是源代码

public class RegReceiptFragment extends Fragment {

    private Context mContext;

    private ListView mRegisteredPLUList;

    private List<String> mDescTestArr;

    private RegReceiptFragmentListAdapter mRegReceiptListAdapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View myFragmentView = inflater.inflate(R.layout.regmain_receipt_layout, container, false);

        mRegisteredPLUList = (ListView) getActivity().findViewById(R.id.reason_list);

        mDescTestArr = new ArrayList<String>();

        testPutListItem(null);

        return myFragmentView;

    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        mContext = getActivity().getBaseContext();

        mRegReceiptListAdapter = new RegReceiptFragmentListAdapter(mContext, R.layout.common_list_item, mDescTestArr);
        if (mRegReceiptListAdapter == null)
            Log.d("masstest", "listview is null!!!");
        else
            mRegisteredPLUList.setAdapter(mRegReceiptListAdapter);
    }

    private void testPutListItem(String value) {
        if (value == null) {
            mDescTestArr.add("BAD!!");
            mDescTestArr.add("HAHAHAHA!!");
            mDescTestArr.add("GEE GEE!!");
        } else {
            mDescTestArr.add(value);
        }

    }
}

public class RegReceiptFragmentListAdapter extends ArrayAdapter<String> {

    private Context mContext;
    private final int mResourceId;
    private List<String> mTestDescArr;

    public RegReceiptFragmentListAdapter(Context context,
            int textViewResourceId, List<String> arry) {
        super(context, textViewResourceId, arry);
        mContext = context;
        mResourceId = textViewResourceId;
        mTestDescArr = arry;
    }

    public View getView(int position, View convertView, ViewGroup parent) {

        ReasonListHolder holder;
        View row = convertView;

        if (row == null) {
            LayoutInflater inflater = (LayoutInflater) mContext
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(mResourceId, parent, false);

            holder = new ReasonListHolder();

            holder.mDescTitle = (TextView) row.findViewById(R.id.list_description);
            holder.mQuantity = (TextView) row.findViewById(R.id.list_quantity);
            holder.mPrice = (TextView) row.findViewById(R.id.list_price);

            row.setTag(holder);
        } else {
            holder = (ReasonListHolder) row.getTag();
        }

        holder.mDescTitle.setText(mTestDescArr.get(position));
        holder.mQuantity.setText(String.valueOf(position));
        holder.mPrice.setText(String.valueOf(position));

        return (row);
    }

    class ReasonListHolder {
        TextView mQuantity;
        TextView mDescTitle;
        TextView mPrice;
    }
}

接下来就是活动

public class MainActivity extends FragmentActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.activity_main);

    // Check whether the activity is using the layout version with
    // the fragment_container FrameLayout. If so, we must add the first fragment
    if (findViewById(R.id.fragment_container) != null) {

        // However, if we're being restored from a previous state,
        // then we don't need to do anything and should return or else
        // we could end up with overlapping fragments.
        if (savedInstanceState != null) {
            return;
        }
    }
}
}

而activity_main.xml是

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" >

        <fragment
            android:id="@+id/fragment_two"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            class="com.sam4s.sample.fragment.test004.RegPLUFragment" />
</FrameLayout>

我找到了原因

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
          ...
          mRegisteredPLUList = (ListView) getActivity().findViewById(R.id.reason_list); 
          ...
    }

此代码应移动到

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    ....
    mRegisteredPLUList = (ListView) getActivity().findViewById(R.id.reason_list); 
    ....
}

这是我在不了解片段生命周期的情况下编写的代码

---

谢谢大家!

托管片段的活动的位置可能重复？

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    ....
    mRegisteredPLUList = (ListView) getActivity().findViewById(R.id.reason_list); 
    ....
}