Question

我尝试在我的应用中实现添加到收藏夹功能。我在列表视图中有两个图像按钮ddToFavouritiesBtn和removeFromFavouritiesBtn。一次只有一个图像按钮在选择时可见。

我的问题是，当我选择addToFavouritiesBtn时，它会被选中，但当我向下滚动列表视图并返回到该图像按钮时，它仍然未被选中。

请告诉我如何在滚动时保持所选项目的状态。

这是我的代码。

public class Product{

  private boolean selected = false;

  public boolean isSelected() {
    return selected;
}

public void setSelected(boolean selected) {
    this.selected = selected;
  }
}

ProdctListAdaptet.class

public class ProductListAdapter extends BaseAdapter {
private Activity activity;
private List<Product> productItems;
private Context context;
int pos;
int flag = 0 ;

public ProductListAdapter(Context context,Activity activity, List<Product> productItems,int flag) {
    this.activity = activity;
    this.productItems = productItems;
    this.context = context;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
   // ProductHolder holder = null;

    final   ProductHolder holder;
    if (convertView == null) {

        holder = new ProductHolder();

        LayoutInflater  inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.product_list_row_item, parent,false);

        holder.thumbNail = (ImageView) convertView
                .findViewById(R.id.product_image);
        holder.title = (TextView) convertView.findViewById(R.id.title);

        holder.btnAddFavourite  = (ImageButton) convertView.findViewById(R.id.AddFavourites);
        holder.btnRemoveFavourite  = (ImageButton) convertView.findViewById(R.id.RemoveFavourites);


        holder.btnAddFavourite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                flag = 1;
                System.out.println("Add favourities");
                pos = (Integer) v.getTag();
                productItems.get(pos).setSelected(false);

                holder.btnAddFavourite.setVisibility(View.GONE);
                holder.btnRemoveFavourite.setVisibility(View.VISIBLE);

                //notifyDataSetChanged();
            }
        });

        holder.btnRemoveFavourite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                flag = 2;
                System.out.println("Remove favorities");
                pos = (Integer) v.getTag();

                productItems.get(pos).setSelected(true);

                holder.btnAddFavourite.setVisibility(View.VISIBLE);
                holder.btnRemoveFavourite.setVisibility(View.GONE);

               // notifyDataSetChanged();

            }
        });
          convertView.setTag(holder);

    } else {

        holder = (ProductHolder) convertView.getTag();
    }

    holder.btnAddFavourite.setTag(position);
    holder.btnRemoveFavourite.setTag(position);

    Product state = productItems.get(position);
    System.out.println("Product position -----> " + state);

    if (state.isSelected()) {

        System.out.println("Selected state ******************* " + state.isSelected());
        System.out.println("selected");
        holder.btnAddFavourite.setVisibility(View.VISIBLE);
        holder.btnRemoveFavourite.setVisibility(View.GONE);
    } else {
        System.out.println("Selected state ******************* " + state.isSelected());
        System.out.println(" not selected");
        holder.btnAddFavourite.setVisibility(View.GONE);
        holder.btnRemoveFavourite.setVisibility(View.VISIBLE);

    }

    convertView.setTag(holder);
    return convertView;
}

    final Product product = (Product) productItems.get(position);
    //final  Product product = (Product) getItem(position);

  holder.thumbNail.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
    holder.title.setText(product.getName());


Picasso.with(activity).load(product.getHref())
            .placeholder(R.drawable.ic_default_banner)
            .into(holder.thumbNail);

private class ProductHolder {
    TextView title;
    ImageView thumbNail;
    ImageButton btnAddFavourite;
    ImageButton btnRemoveFavourite;
}

}

Answer 1

在按钮onclick功能中更改数据集后，必须使用youradapetr.notifydatasetchanged（），在您的情况下，只需添加notifyDataSetChanged（）;如下所示两个函数

        holder.btnAddFavourite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                System.out.println("Add favourities");
                int pos = (Integer) v.getTag();
                productItems.get(pos).setSelected(false);

                holder.btnAddFavourite.setVisibility(View.GONE);
             holder.btnRemoveFavourite.setVisibility(View.VISIBLE);
notifyDataSetChanged();
            }
        });

Answer 2

我认为问题出在onClickListener中。使用作为参数而不是pos的位置来设置监听器内的状态。

holder.btnAddFavourite.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            System.out.println("Add favourities");
            productItems.get(position).setSelected(false);
            holder.btnAddFavourite.setVisibility(View.GONE);
            holder.btnRemoveFavourite.setVisibility(View.VISIBLE);
        }
    });

holder.btnRemoveFavourite.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            System.out.println("Remove favorities");
            productItems.get(position).setSelected(true);

            holder.btnAddFavourite.setVisibility(View.VISIBLE);
            holder.btnRemoveFavourite.setVisibility(View.GONE);

        }
    });

编辑1： -

你可以尝试下面的getView方法。我认为你在onclick监听器中设置了错误的状态。您在btnRemoveFavourite中设置setSelected（true）但它应该是setSelected（false）。同样适用于btnAddFavorite。

如果正确，请尝试以下代码并接受答案。

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

    final ProductHolder holder = null;
    if (convertView == null) {

        holder = new ProductHolder();

        LayoutInflater inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.product_list_row_item, parent, false);

        holder.thumbNail = (ImageView) convertView.findViewById(R.id.product_image);
        holder.title = (TextView) convertView.findViewById(R.id.title);
        holder.btnAddFavourite = (ImageButton) convertView.findViewById(R.id.AddFavourites);
        holder.btnRemoveFavourite = (ImageButton) convertView.findViewById(R.id.RemoveFavourites);

        convertView.setTag(holder);

    } else {

        holder = (ProductHolder) convertView.getTag();
    }

    final Product product = productItems.get(position);

    holder.btnAddFavourite.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            product.setSelected(true);

            holder.btnAddFavourite.setVisibility(View.GONE);
            holder.btnRemoveFavourite.setVisibility(View.VISIBLE);

        }
    });

    holder.btnRemoveFavourite.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            product.setSelected(false);

            holder.btnAddFavourite.setVisibility(View.VISIBLE);
            holder.btnRemoveFavourite.setVisibility(View.GONE);

        }
    });

    if (product.isSelected()) {

        System.out.println("Selected state ******************* " + state.isSelected());
        System.out.println("selected");
        holder.btnAddFavourite.setVisibility(View.GONE);
        holder.btnRemoveFavourite.setVisibility(View.VISIBLE);
    } else {
        System.out.println("Selected state ******************* " + state.isSelected());
        System.out.println(" not selected");
        holder.btnAddFavourite.setVisibility(View.VISIBLE);
        holder.btnRemoveFavourite.setVisibility(View.GONE);

    }

    return convertView;
}

Answer 3

问题：

您的适配器中的

getView（）会不时被调用。因此，如果没有为按钮设置选定状态，它将恢复到原始状态。

解决方案：

使用getter和setter在模型类[Product]中保留一个布尔值：

boolean didSelect;

 public boolean isDidSelect() {
        return didSelect;
    }

public void setDidSelect(boolean didSelect) {
        this.didSelect = didSelect;
    }

在getView（）中，根据布尔值中的值设置按钮的选择。

Answer 4

这里我给你一个简单的演示，你可以根据你的要求更新它，我希望你能得到你的解决方案。

公共类MainActivity扩展了Activity {

String s[] = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L",
        "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y",
        "Z" };

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    List<Product> products = new ArrayList<Product>();
    ListView list = (ListView) findViewById(R.id.listview);
    for (int i = 0; i < s.length; i++) {
        Product item = new Product();
        item.setCheck(false);
        item.setName(s[i].toString());
        products.add(item);
    }
    ProductListAdapter ac = new ProductListAdapter(MainActivity.this, R.layout.row,
            products);

    list.setAdapter(ac);

}// on create method end

class ProductListAdapter extends BaseAdapter {

    private List<Product> productItems;

    Context context;
    int layoutId;



    public ProductListAdapter(Context context, int layoudId, List<Product> productItems) {
        // super(context,productItems);

        this.layoutId = layoudId;
        this.context = context;
        this.productItems = productItems;


    }

    public class ProductHolder {
        ImageView image;

        TextView name;

    }

    @Override
    public View getView(final int position, View convertView,
            ViewGroup parent) {
        final ProductHolder holder;
        Product rowitems = productItems.get(position);
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            convertView = mInflater.inflate(layoutId, parent, false);
            holder = new ProductHolder();

            holder.name = (TextView) convertView.findViewById(R.id.name);

            holder.image = (ImageView) convertView
                    .findViewById(R.id.invite_click);
            holder.image.setBackgroundResource(R.drawable.green);
            convertView.setTag(holder);

        }

        else {
            holder = (ProductHolder) convertView.getTag();

        }

        holder.image.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                if (productItems.get(position).isCheck) {
                    productItems.get(position).isCheck = false;
                    // holder.image.setImageBitmap(null);
                    holder.image.setBackgroundResource(R.drawable.green);

                } else {
                    productItems.get(position).isCheck = true;
                    holder.image
                            .setBackgroundResource(R.drawable.green_tick);
                }

            }
        });

        if (productItems.get(position).isCheck) {

            productItems.get(position).isCheck = true;
            holder.image.setBackgroundResource(R.drawable.green_tick);

        } else {
            productItems.get(position).isCheck = false;
            holder.image.setImageBitmap(null);
            holder.image.setBackgroundResource(R.drawable.green);
        }
        holder.name.setText(rowitems.getName());

        Log.e("name----->", productItems.get(position).toString());

        return convertView;
    }

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

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

    @Override
    public long getItemId(int position) {
        return productItems.indexOf(getItem(position));
    }

}

}

滚动时保持所选列表视图图像按钮的状态

4 个答案: