notifyDataSetChanged() 从 DialogFragment 到片段中的 GridView 适配器

Question

我有一个 Main activity，它包含 NavigationDrawerFragment（取自 android studio 模板） GridViewAdapter 有 OnLongClickListener，它通过 Main:

中的回调运行 SettingsFragment

主要内容：

  public void ShowSettings(Drink drink, int position) {
        // DialogFragment.show() will take care of adding the fragment
        // in a transaction.  We also want to remove any currently showing
        // dialog, so make our own transaction and take care of that here.
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        Fragment prev = getFragmentManager().findFragmentByTag("dialog");
        if (prev != null) {
            ft.remove(prev);
        }
        ft.addToBackStack(null);
        // Create and show the dialog.
        DialogFragment settings = FragmentSettings.newInstance(drink, position);

        settings.show(ft, "FragmentSettings");

网格视图适配器：

public class GridViewAdapter extends BaseAdapter implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener {

    private ArrayList<Drink> listDrink = new ArrayList<Drink>();
    private Activity activity;
    private Context mContext;
    private GridViewAdapterCallback callback;

    public GridViewAdapter(Activity activity, ArrayList<Drink> listDrink) {
        super();
        this.listDrink = listDrink;
        this.activity = activity;
    }

    public GridViewAdapter(Context c) {
        mContext = c;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return listDrink.size();
    }

    @Override
    public Drink getItem(int position) {
        // TODO Auto-generated method stub
        return listDrink.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }




    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder view;
        LayoutInflater inflator = activity.getLayoutInflater();
        if (convertView == null) {
            view = new ViewHolder();
            convertView = inflator.inflate(R.layout.grid_item, null);

            view.txtViewTitle = (TextView) convertView.findViewById(R.id.tvName);

            view.imgViewFlag = (ImageView) convertView.findViewById(R.id.imageView1);

            view.txtViewCount = (TextView) convertView.findViewById(R.id.tvCount);

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

        view.txtViewTitle.setText(listDrink.get(position).getProductName());
        switch (listDrink.get(position).getType()) {
            case (1):
                view.imgViewFlag.setImageResource(R.drawable.btn_beer);
                break;
            case (2):
                view.imgViewFlag.setImageResource(R.drawable.btn_dark);
                break;
            default:
                view.imgViewFlag.setImageResource(R.drawable.btn_shot);
                break;


        }

        int count = callback.SqliteCountProducts(listDrink.get(position).getProductName());
        view.txtViewCount.setText(String.valueOf(count));
//        notifyDataSetChanged();

        return convertView;
    }

    public void setCallback(GridViewAdapterCallback callback) {

        this.callback = callback;
    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//        Log.d("My_Log", "On_click:" + position);
        callback.SqliteSave(listDrink.get(position));
        notifyDataSetInvalidated();


    }


    @Override
    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
//        Log.d("My_Log", "On_long_click:" + position);
        callback.ShowSettings(listDrink.get(position), position);
        notifyDataSetInvalidated();
        return true;
    }

    public void UpdateGrid() {
        notifyDataSetInvalidated();

    }


    public interface GridViewAdapterCallback {

        public int SqliteCountProducts(String product);

        public void SqliteSave(Drink drink);

        public void ShowSettings(Drink drink, int position);
    }

    public static class ViewHolder {
        public ImageView imgViewFlag;
        public TextView txtViewTitle;
        public TextView txtViewCount;
    }


}

GridFragment，包含 GridViewAdapter

public class GridFragment extends Fragment {
    //    ArrayList<Drink> listDrink = new ArrayList<Drink>();
    public GridViewAdapter mAdapter;

    public GridFragment() {
        // Required empty public constructor
    }

    public static GridFragment newInstance() {
        GridFragment fragment = new GridFragment();
        return fragment;
    }



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_grid, container, false);
        // prepared arraylist and passed it to the Adapter class
        mAdapter = new GridViewAdapter(getActivity(), ((Main) getActivity()).PrepareDefaultArray());
        GridView gridView = (GridView) view.findViewById(R.id.gvMain);

        mAdapter.setCallback((GridViewAdapter.GridViewAdapterCallback) view.getContext());
        gridView.setAdapter(mAdapter);
        gridView.setOnItemClickListener(mAdapter);
        gridView.setOnItemLongClickListener(mAdapter);



        return view;
    }

    @Override
    public void onResume() {

        super.onResume();
        UpdateArray();


    }
    public void UpdateArray() {
        mAdapter.notifyDataSetChanged();

    }

onResume 有效，但仅在 GridView 项目滑到屏幕后方并返回后才有效

我不知道如何让它正常工作。 :/

内容提供商？

我无法对 main 进行另一个回调 - 因为它会导致循环

感谢您的帮助

Answer 1

为什么将 UpdateArray() 放在 onCreate() 中？ mAdapter 尚未实例化。

@Override public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    UpdateArray();


}

所以在 gridView.setAdapter(mAdapter);

之后将 UpdateArray() 从 onCreate() 移动到 onCreateView()

更新：

并评论 notifyDataSetInvalidated ()，因为：

public void notifyDataSetInvalidated (): Notifies the attached observers that the underlying data is no longer valid or available. Once invoked this adapter is no longer valid and should not report further data set changes.

notifyDataSetChanged() 从 DialogFragment 到片段中的 GridView 适配器

notifyDataSetChanged() from DialogFragment to GridView adapter in a fragment

android

callback

android-arrayadapter

android-fragments