Question

我正在制作一个餐厅应用程序，其中包含食品项目列表，用户可在其中添加或减去食品项目。我的问题是，每当点击添加按钮时，它会增加该食物项值，但是在向下滚动列表或向上滚动之后。它的值变为初始状态。我已经在Stackoverflow和许多其他网站上搜索过有关此问题的所有问题，但没有任何帮助。我试过ViewHolder，setfocuschangelistener等等我知道问题是回收由android完成的东西请任何人都可以告诉我该怎么做才能解决我的问题

这是我的自定义适配器类：

public class CustomAdapter extends ArrayAdapter<String> {

String costing;
ImageView add;
int totalCost;
loggedIn loggedIn;

public CustomAdapter(Context context, String[] foods) {
    super(context,R.layout.custom_row ,foods);
}

static class ViewHolder{

    TextView foodItem;
    TextView noOfFoodItem;
    ImageView minus;
    ImageView add;
    TextView cost;

}



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

    final ViewHolder holder;

    LayoutInflater layoutInflater = LayoutInflater.from(getContext());

    if(convertView==null) {

        convertView = layoutInflater.inflate(R.layout.custom_row, parent, false);

        holder = new ViewHolder();

        holder.foodItem = (TextView) convertView.findViewById(R.id.foodItem);
        holder.cost = (TextView) convertView.findViewById(R.id.cost);
        holder.minus = (ImageView) convertView.findViewById(R.id.minus);
        holder.noOfFoodItem = (TextView) convertView.findViewById(R.id.noOfFoodItem);
        holder.add = (ImageView) convertView.findViewById(R.id.add);

        convertView.setTag(holder);

    }else{

        holder = (ViewHolder)convertView.getTag();

    }

    try{

        String[] foodItems = {"Burger               ","Pizza                 ","Cold Drinks      ",
                "Coffee               ","Burger               ","Pizza                 ",
                "Cold Drinks      ","Coffee               ","Burger               ",
                "Pizza                 ","Cold Drinks      ","Coffee               ","Burger               ",
                "Pizza                 ",
                "Cold Drinks      ","Coffee                "};
        holder.foodItem.setText(foodItems[position]);

        String[] costs = {"Rs.70","Rs.80","Rs.70","Rs.80","Rs.70","Rs.80","Rs.70","Rs.80","Rs.70","Rs.80","Rs.70","Rs.80"};
        holder.cost.setText(costs[position]);

        holder.minus.setImageResource(R.drawable.minus);

        holder.noOfFoodItem.setText("0");

        holder.add.setImageResource(R.drawable.add);

    }catch (Exception e){

        e.printStackTrace();

    }

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

            //Getting items selected of any food item
            if(holder.noOfFoodItem.getText().toString().equals("9")){

                Toast.makeText(getContext(),"Maximum limit reached!",Toast.LENGTH_SHORT).show();
                holder.noOfFoodItem.setText("9");

            }else
             holder.noOfFoodItem.setText(String.valueOf(Integer.parseInt(holder.noOfFoodItem.getText().toString())+1));

        }
    });

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

            if(holder.noOfFoodItem.getText().toString().equals("0")){

                Toast.makeText(getContext(),"Do you need some medical attention?",Toast.LENGTH_SHORT).show();
                holder.noOfFoodItem.setText("0");

            }else{

            holder.noOfFoodItem.setText(String.valueOf(Integer.parseInt(holder.noOfFoodItem.getText().toString())-1));
        }
        }
    });

    return convertView;


}

}

Answer 1

哟需要保持列表中每个项目的价值不被回收。您可以使用HashMap并将noOfFoodCount放在hasmap中，其中position为position，food count为value。

Answer 2

您只是在当前文本中添加或减去该值。您必须创建一个用于保存这些计数的arraylist。

创建像ArrayList<Integer> count=new ArrayList<Integer>;这样的arraylist 然后在添加时，

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

        //Getting items selected of any food item
        if(holder.noOfFoodItem.getText().toString().equals("9")){

            Toast.makeText(getContext(),"Maximum limit reached!",Toast.LENGTH_SHORT).show();
            holder.noOfFoodItem.setText("9");

            count.add(9);

        }else {
           holder.noOfFoodItem.setText(String.valueOf(Integer.parseInt(holder.noOfFoodItem.getText().toString())+1));
           count.add(Integer.parseInt(holder.noOfFoodItem.getText().toString())+1);
     }
    }
});

如果减少计数，

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

        if(holder.noOfFoodItem.getText().toString().equals("0")){

            Toast.makeText(getContext(),"Do you need some medical attention?",Toast.LENGTH_SHORT).show();
            holder.noOfFoodItem.setText("0");

              count.add(0);

        }else{
           holder.noOfFoodItem.setText(String.valueOf(Integer.parseInt(holder.noOfFoodItem.getText().toString())-1));
           count.add(Integer.parseInt(holder.noOfFoodItem.getText().toString())-1);
     }
    }
});

希望你理解。

Answer 3

添加全局变量

List<String> foodItems;

将构造函数更改为

 public CustomAdapter(Context context, String[] foods) {
        super(context,R.layout.custom_row ,foods);
     foodItems=Arrays.asList(foods);
    }

并修改onClickListerner上的添加按钮阻止

else{
    foodItems.add("add your item name here");
    holder.noOfFoodItem.setText(foodItems.size());

    }

如果您需要任何清晰度，请告诉我

android列表项简单TextView在滚动后更改为初始状态

3 个答案: