Android Fragment BaseAdapter 不工作

Question

此代码在 Activity 中正常工作，我将所有 Context 更改为 getActivity()

但是在 adapter=new ListViewAdapter(getActivity(), arraylist); 之后将其复制到 Fragment 时出现错误当 mylist.setAdapter(adapter) 为运行时，我的 class ListViewAdapter 错误如何解决？

片段

public class Fragment1 extends Fragment  {

DataBaseHelper myDbHelper;

ListView mylist;
ArrayList<String> iran,arr_intityid,arrshomare,primarykeyarrlist;
String[] fa,mysid,myshomare,primarykeyarr;
SQLiteDatabase db;
Cursor mCursor;
int translate;
EditText mysearch;
int [] favorit;
ArrayList<Integer> favor;
ListViewAdapter adapter;


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

    View myview = inflater.inflate(R.layout.search_fragment, container, false);

    mylist=(ListView) myview.findViewById(R.id.mylist);

    return myview;

}

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    myDbHelper = new DataBaseHelper(getActivity().getApplicationContext());
    myDbHelper = new DataBaseHelper(getActivity());
    iran=new ArrayList<String>();
    arr_intityid=new ArrayList<String>();
    arrshomare=new ArrayList<String>();
    primarykeyarrlist=new ArrayList<String>();
    favor=new ArrayList<Integer>();

    try {

        myDbHelper.createDataBase();

    }                   

    catch (IOException ioe) {
        throw new Error("Unable to create database");
            }

    try {
                            myDbHelper.openDataBase();

    }       


    catch (SQLException sqle) {

        sqle.printStackTrace();

    }


    ArrayList<myitems> arraylist = new ArrayList<myitems>();
    db = myDbHelper.getReadableDatabase();

    mCursor= db.rawQuery("SELECT field_translation_id_value,title,translate,my_id,favorites  FROM khotbe"
            + " WHERE translate =1 ORDER BY field_translation_id_value ASC   ;",null);

    int i = 1;

    mCursor.moveToFirst();

    while (mCursor.isAfterLast() == false) {


        iran.add(mCursor.getString(1));
        arr_intityid.add(mCursor.getString(0));
        primarykeyarrlist.add(mCursor.getString(3));
        favor.add(mCursor.getInt(4));
        arrshomare.add(""+i++);
        mCursor.moveToNext();

}

     fa= new String [iran.size()];
     fa=iran.toArray(fa);
        mysid= new String [arr_intityid.size()];                        
       mysid=arr_intityid.toArray(mysid);
        primarykeyarr= new String [primarykeyarrlist.size()];                       
       primarykeyarr=primarykeyarrlist.toArray(primarykeyarr);
        myshomare=new String[arrshomare.size()];
       myshomare=arrshomare.toArray(myshomare);

       favorit =new int[favor.size()];
       for (int t= 0; t < favor.size(); t++) {

      favorit[t]=favor.get(t).intValue();

    }

       mCursor.moveToPosition(0);

       for (int j = 0; j < fa.length; j++) {


         myitems qqq= new myitems(fa[j],mysid[j],myshomare[j],primarykeyarr[j],favorit[j]);

           arraylist.add(qqq);

       }

       Log.i("sssssss",getActivity()+"");

       adapter=new ListViewAdapter(getActivity(), arraylist);
       Log.i("sssssss", "2222222222222");

       mylist.setAdapter(adapter);


}

class ListViewAdapter

public class ListViewAdapter extends BaseAdapter {

        LayoutInflater inflater;
        private List<myitems> worldpopulationlist = null;
        private ArrayList<myitems> arraylist;
        int myfavorit =0;


        public ListViewAdapter(Context context, List<myitems> worldpopulationlist) {
        //  mContext = context;
            this.worldpopulationlist = worldpopulationlist;

            inflater = LayoutInflater.from(getActivity());

            this.arraylist = new ArrayList<myitems>();
            this.arraylist.addAll(worldpopulationlist);
        }

        public class ViewHolder {
            TextView rank;
            TextView country;
            TextView population;
            Button btn;

        }

        @Override
        public int getCount() {
            return worldpopulationlist.size();
        }

        @Override
        public myitems getItem(int position) {
            return worldpopulationlist.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        public View getView(final int position, View view, ViewGroup parent) {
            final ViewHolder holder;
            if (view == null) {
                holder = new ViewHolder();


                view = inflater.inflate(R.layout.myitems_list, null);

                holder.rank = (TextView) view.findViewById(R.id.txt25);
                holder.btn=(Button) view.findViewById(R.id.btnfavor);

                holder.country = (TextView) view.findViewById(R.id.txt26);

                view.setTag(holder);
            } else {
                holder = (ViewHolder) view.getTag();
            }


            holder.rank.setText(worldpopulationlist.get(position).gettitle());

            holder.country.setText(worldpopulationlist.get(position).getshomare()+"-");


            if(myfavorit==0){
                holder.btn.setBackgroundResource(R.drawable.ic_launcher);

            }

            else{
                holder.btn.setBackgroundResource(R.drawable.star);

            }


            return view;

        }
        }

Answer 1

因为onCreate方法比onCreateView触发的早

onCreateView方法中一定是这样

mylist=(ListView) myview.findViewById(R.id.mylist);

adapter = new ListViewAdapter(getActivity(), arraylist);
mylist.setAdapter(adapter);

P.S。请访问 http://developer.android.com/guide/components/fragments.html

和

https://source.android.com/source/code-style.html

Android Fragment BaseAdapter 不工作

Android Fragment BaseAdapter not working

android

fragment

baseadapter