Question

public class MyCustomAdapter extends BaseAdapter {
    Context context;
    String[] result;
    int[] imageId;
    String[] Cost;
    static int counter = 0;
    private static LayoutInflater inflater = null;


    public MyCustomAdapter(Context mainActivity, String[] result, int[] imageId, String[] Cost
    ) {
        // TODO Auto-generated constructor stub
        this.result = result;
        this.imageId = imageId;
        this.Cost = Cost;
        this.context = mainActivity;
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

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

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

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

    public class Holder {
        TextView tv;
        TextView cost;
        ImageView img;
        ImageView plusitem;
        ImageView minusitem;
        TextView itemnumber;

    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        final Holder holder = new Holder();
        View rowView;
        rowView = inflater.inflate(R.layout.listitem, null);
        holder.tv = (TextView) rowView.findViewById(R.id.textView1);
        holder.img = (ImageView) rowView.findViewById(R.id.imageView1);
        holder.cost = (TextView) rowView.findViewById(R.id.textView2);
        holder.plusitem = (ImageView) rowView.findViewById(R.id.imageButton2);
        holder.minusitem = (ImageView) rowView.findViewById(R.id.imageButton);
        holder.itemnumber = (TextView) rowView.findViewById(R.id.textView4);
        holder.tv.setText(result[position]);
        holder.img.setImageResource(imageId[position]);

        holder.plusitem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {


                holder.itemnumber.setText(String.valueOf( _counter));
                //holder.itemnumber.setText(result[position]);

            }
        });

        holder.minusitem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                holder.itemnumber.setText(String.valueOf( _counter));
                //  holder.itemnumber.setText(result[position]);
            }
        });


        return rowView;

    }}

这是我的适配器，我们有+按钮用于增加项目和 - 按钮对于减少项目我必须得到第一项中的项目编号如果我们有2项和第二项我们可以3,4 ..所以.. 现实我想在车上添加项目实际上我尝试使用静态变量，它不能正常工作请告诉我逻辑。看下面的屏幕

Answer 1

创建设计中显示的Buttons和TextView。为onclick编写Buttons方法。初始化Integer变量以保存计数。单击+按钮，将计数递增1并在Textview中设置文本。同样，单击 - 按钮时，将计数减1并在TextView中设置文本。

  int count=0;
    TextView txtCount =(TextView) findViewById(R.id.txt);
    Button buttonInc= (Button) findViewById(R.id.button1);
    Button buttonDec= (Button) findViewById(R.id.button2);

    buttonInc.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            count++;
            txtCount.setText(String.valueOf(count));

        }
    });

buttonDec.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            count--;
            txtCount.setText(String.valueOf(count));

        }
    });

Answer 2

使用哈希映射。对于每个单击的项目，将项目ID存储为键，将点击的计数存储为值。

例如：<Item_id:item_count>

通过这种方式，您可以轻松管理用户的选择，并且比使用静态变量更有效，因为您只需要一个哈希映射。

Answer 3

首先，您应该维护一个自定义类的arraylist，其中包含ItemId，ItemName，Price，Quantity，Image等字段。这样您就可以轻松地在购物车中维护数量和其他细节。

现在在适配器中你只需要传递这个arrayList，不需要传递不同的数组。

int quantity = arraylist.get(position).getItemQuantity();

btnIncrease.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            quantity++;
            tvQuantity.setText(quantity+"");

        }
    });

btnDecrease.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            quantity--;
            tvQuantity.setText(quantity+"");

        }
    });

这很有效......

Answer 4

这是适配器添加到购物车中你可以在btnIncrease和btnDecrease上看到我改变购物车的价值而我使用notifyDataSetChanged（）;它会自动更改数据

public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {
    private List<Movie> moviesList;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView title, cart, genre;
        public Button btnIncrease,btnDecrease;

        public MyViewHolder(View view) {
            super(view);
            title = (TextView) view.findViewById(R.id.title);
            genre = (TextView) view.findViewById(R.id.genre);
            cart = (TextView) view.findViewById(R.id.cart);
            btnIncrease =view.findViewById(R.id.plus);
            btnDecrease = view.findViewById(R.id.minus);

        }
    }


    public MoviesAdapter(List<Movie> moviesList) {
        this.moviesList = moviesList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.movie_list_row, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        final Movie movie = moviesList.get(position);
        holder.title.setText(movie.getTitle());
        holder.genre.setText(movie.getGenre());
        holder.cart.setText(String.valueOf(movie.getcart()));
        holder.btnIncrease.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                movie.cart++;
                notifyDataSetChanged();
            }
        });

        holder.btnDecrease.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if (movie.cart>0)
                     movie.cart--;

                notifyDataSetChanged();
            }
        });

    }

    @Override
    public int getItemCount() {
        return moviesList.size();
    }
}

Answer 5

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

//1. List item

        @Override
        public void onClick(View v) {
            int count= Integer.parseInt(String.valueOf(holder.cart_product_quantity_tv.getText()));

            if(count>0){

 //2. enter code here

                count--;

                holder.cart_product_quantity_tv.setText(String.valueOf(count));
            }
        }
    });

    holder.cart_plus_img.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int count= Integer.parseInt(String.valueOf(holder.cart_product_quantity_tv.getText()));
            count++;
            holder.cart_product_quantity_tv.setText(String.valueOf(count));
        }
    });

如何为每个项目按钮设置值增加和减少单击并在文本视图中设置该值

5 个答案: