自定义适配器getView提供NullPointException

Question

我有一个listView需要定制的适配器-Dict_Adapter。 Dict_Adapter的构造函数之一是：

public Dict_Adapter(Context c,ArrayList<String> Meanings){
    context=c;
    meaning=Meanings;
    type=2;
}

在适配器的getView中，应用程序将设置两个TextView和一个ImageView，如下所示：

 @Override
public View getView(int i, View view, ViewGroup viewGroup) {
    if (view==null) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.dict_listview_items, null);
    }
    TextView Difficulty=(TextView) view.findViewById(R.id.Dict_ListView_Difficulty);
    TextView Word=(TextView) view.findViewById(R.id.Dict_ListView_Word);
    ImageView Arrow=(ImageView) view.findViewById(R.id.Dict_ListView_Arrow);
    if (type==2){
        Difficulty.setText(difficulty.get(i));
        Word.setText(meaning.get(i));
        Arrow.setVisibility(View.INVISIBLE);
    }
    return view;

难度和Word是两个向TextViews提供内容的ArrayLists。

在Activity Daily_Word.java中，Dict_Adapter将在下面应用：

ListView Daily_Word_Meaning_List=(ListView) findViewById(R.id.Daily_Word_Meaning_List);
    String sourceMeaning=c.getString(1);
    Log.w("SourceMeaning",sourceMeaning);
    ArrayList<String> meaningList=new ArrayList<>(Arrays.asList(sourceMeaning.split("&")));
    for (int i=0; i<meaningList.size();i++){
        Log.w("Meaning",meaningList.get(i));
    }
    Dict_Adapter adapter1=new Dict_Adapter(getBaseContext(),meaningList);
    Daily_Word_Meaning_List.setAdapter(adapter1);

然后出现问题：应用程序抛出NullPointerException：

07-06 23:01:38.513 341-341/com.android.luftschlafer.wordenhancement E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                  java.lang.NullPointerException
                                                                                      at com.android.luftschlafer.wordenhancement.Adapters.Dict_Adapter.getView(Dict_Adapter.java:103)

这意味着什么     Difficulty.setText（difficulty.get（I））; 给出了nullpointerexception。

如何克服这个问题？我已经在“dict_listview_items”中部署了布局和小部件。