将项目加载到网格时它有空网格

Question

当我在 gridview 上工作时，我遇到了以下问题，我们将不胜感激，

当我将数据加载到我的 gridview 时，它加载了所有 18 个项目。（Log.i 它显示了我 LogCat 中的所有 18 个项目，因为我使用了 if 条件 ((object.getString("MainCategoryID")).equals("1")) ).但它也会加载 10 个空网格。为什么它加载其他 10 个空网格。

由于MainCategoryID=1的item只有18个，应该只加载18个grid，但是这里加载了28个grid（因为responseJson里面有28个item）。我想将它限制为 18 个网格并删除空网格。

当我加载时它看起来像这样

列表片段class

 public class PizzaFragment extends ListFragment implements OnTaskCompleted {

    GridView grid;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.menu_grid_main, container, false);

        new PizzaMenuAsyncTask(getActivity(), this).execute();

        mQuickReturnView = (TextView) view.findViewById(R.id.footer);
        mQuickReturnView1 = (TextView) view.findViewById(R.id.footer1);
        mQuickReturnView2 = (TextView) view.findViewById(R.id.footer2);

        grid = (GridView) view.findViewById(R.id.grid);
        return view;
    }

    @Override
    public void onTaskCompleted(JSONArray responseJson) {

        try {
            String[] Description = new String[responseJson.length()];
            String[] ImageURL = new String[responseJson.length()];

            for (int i = 0; i < responseJson.length(); i++) {
                JSONObject object = responseJson.getJSONObject(i);
                if ((object.getString("MainCategoryID")).equals("1")) {
                    Log.i("MainCategoryID ", object.getString("MainCategoryID"));
                    ImageURL[i] = object.getString("ImageURL");
                    Log.i("MainCategoryID ", object.getString("Description"));
                    Description[i] = object.getString("Description");

                    CustomGrid adapter = new CustomGrid(getActivity(), Description,
                            ImageURL);
                    grid.setAdapter(adapter);
                }
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

自定义网格class

public class CustomGrid extends BaseAdapter {

    private Context context;
    private Context mContext;
    private final String[] Description;
    private final String[] ImageURL;

    public CustomGrid(Context c, String[] Description, String[] ImageURL) {
        this.context = c;
        this.Description = Description;
        this.ImageURL = ImageURL;
    }

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

    @Override
    public Object getItem(int position) {
        return Description[position];
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(
                    R.layout.fragment_pizza, parent, false);
            holder.ivImage = (ImageView) convertView
                    .findViewById(R.id.grid_image);
            holder.tvHeader = (TextView) convertView
                    .findViewById(R.id.grid_text);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.tvHeader.setText(Description[position]);
        Picasso.with(this.context).load(ImageURL[position]).into(holder.ivImage);

        return convertView;
    }

    private class ViewHolder {
        private TextView tvHeader;
        private ImageView ivImage;
    }
}

Answer 1

这是因为在 CustomGrid class 的 getCount() 方法中，您要返回 Description[] 数组的大小；和 String[] Description = new String[responseJson.length()];，连同 ListFragment class 中的 CustomGrid adapter = new CustomGrid(getActivity(), Description, ImageURL); 导致网格看到 28 个项目（Description[] 数组的大小）而不是 18 个具有 "MainCategoryID" 的项目1.

您可能需要重写 public void onTaskCompleted(JSONArray responseJson) 方法，以便只存储符合条件的项目的描述和图像 URL。而且

CustomGrid adapter = new CustomGrid(getActivity(), Description, ImageURL);
grid.setAdapter(adapter);

可以在循环之外，在您已经准备好数据之后。

我继续为您重写下面的代码：

public class PizzaFragment extends ListFragment implements OnTaskCompleted {
    GridView grid;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.menu_grid_main, container, false);

        new PizzaMenuAsyncTask(getActivity(), this).execute();

        mQuickReturnView = (TextView) view.findViewById(R.id.footer);
        mQuickReturnView1 = (TextView) view.findViewById(R.id.footer1);
        mQuickReturnView2 = (TextView) view.findViewById(R.id.footer2);

        grid = (GridView) view.findViewById(R.id.grid);
        return view;
    }

    @Override
    public void onTaskCompleted(JSONArray responseJson) {
        try {
            List<String> descriptions = new ArrayList<String>();
            List<String> imageUrls = new ArrayList<String>();

            for (int i = 0; i < responseJson.length(); ++i) {
                JSONObject object = responseJson.getJSONObject(i);

                if ((object.getString("MainCategoryID")).equals("1")) {
                    Log.i("ImageURL ", object.getString("ImageURL"));

                    imageUrls.add(object.getString("ImageURL"));

                    Log.i("Description ", object.getString("Description"));

                    descriptions.add(object.getString("Description"));
                }
            }

            CustomGrid adapter = new CustomGrid(getActivity(), descriptions, imageUrls);
            grid.setAdapter(adapter);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

和

public class CustomGrid extends BaseAdapter {
    private Context context;
    private Context mContext;
    private final List<String> descriptions;
    private final List<String> imageUrls;

    public CustomGrid(Context c, List<String> descriptions, List<String> imageUrls) {
        this.context = c;
        this.descriptions = descriptions;
        this.imageUrls = imageUrls;
    }

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

    @Override
    public Object getItem(int position) {
        return descriptions.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(
                    R.layout.fragment_pizza, parent, false);
            holder.ivImage = (ImageView) convertView
                    .findViewById(R.id.grid_image);
            holder.tvHeader = (TextView) convertView
                    .findViewById(R.id.grid_text);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.tvHeader.setText(descriptions.get(position));
        Picasso.with(this.context).load(imageUrls.get(position)).into(holder.ivImage);

        return convertView;
    }

    private class ViewHolder {
        private TextView tvHeader;
        private ImageView ivImage;
    }
}

注意：我改用 List 而不是 Array，并修复了一些代码风格问题。我没有测试这个。您应该自己尝试该示例并查阅文档以获取更多信息。另请阅读 the Google Java Style 以获得良好的 Java 风格指南。

将项目加载到网格时它有空网格

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