Question

我使用SQLITE数据库存储列表项，使用 Baseadapter 在我的应用程序中显示listview。

列表视图中的每个项目都有编辑文本值，默认值为1。当用户将值从1更改为2时，必须在数据库中更新该值。

此更新必须在适配器内完成。

以下是我更改编辑文本值的适配器代码。

public class CustomAdapter_cart extends BaseAdapter  {
ArrayList<String> list_name = new ArrayList<String>();
ArrayList<String> list_price = new ArrayList<String>();
ArrayList<String> list_images = new ArrayList<String>();
ArrayList<String> list_model = new ArrayList<String>();
ArrayList<String> list_productid = new ArrayList<String>();
ArrayList<Integer> ids = new ArrayList<Integer>();
CustomAdapter_cart cart_refresh;
Bitmap b;

Context context;
AddToCart cart;
String value,name,price,image_new,model,product,qty;
private static LayoutInflater inflater = null;
Cursor cu;
String quant;
Holder holder = new Holder();
SharedPreferences sharedpreferences;
ArrayList<String>listMessages = new ArrayList<String>(new LinkedHashSet<String>());

ArrayList<String> quant_items = new ArrayList<String>();
Cursor mCursor;
ContentValues data=new ContentValues();
String model_item;
String id;
int id_final;


public CustomAdapter_cart(Context context, ArrayList<String> list_name, ArrayList<String> list_price, ArrayList<String> bitmapArray, ArrayList<String> list_model, ArrayList<String> list_productid,ArrayList<String> qty, ArrayList<Integer>ids ) {
    this.context = context;
    this.list_name = list_name;
    this.list_price = list_price;
    this.list_images = bitmapArray;
    this.list_model = list_model;
    this.list_productid = list_productid;
    this.quant_items = qty;
    this.cart_refresh = this;
    this.ids = ids;

    inflater = LayoutInflater.from(context);
}

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

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

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



public class Holder {
    TextView tv_name, tv_price, tv_model,tv_product,tv_id;
    ImageView image;
    Button delete;
    EditText quantity;

}


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

    View rowView = convertView;

    if (convertView == null) {

        // TODO Auto-generated method stub
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);


        rowView = inflater.inflate(R.layout.list_items_cart, null);


        holder.tv_name = (TextView) rowView.findViewById(R.id.name_cart);
        holder.tv_price = (TextView) rowView.findViewById(R.id.price_cart);
        holder.image = (ImageView) rowView.findViewById(R.id.image_cart);
        holder.tv_model = (TextView) rowView.findViewById(R.id.model_cart);
        holder.tv_product = (TextView) rowView.findViewById(R.id.product_cart);
        holder.delete = (Button) rowView.findViewById(R.id.delete);
        holder.quantity = (EditText) rowView.findViewById(R.id.quantity);
        holder.tv_id = (TextView)rowView.findViewById(R.id.ids);
        rowView.setTag(holder);



    }
    else

        holder = (Holder) rowView.getTag();

    holder.tv_name.setText(list_name.get(position));
    name = holder.tv_name.getText().toString();
    holder.tv_price.setText(list_price.get(position));
    price = holder.tv_price.getText().toString();
    holder.tv_model.setText(list_model.get(position));
    model = holder.tv_model.getText().toString();
    holder.tv_product.setText(list_productid.get(position));
    product = holder.tv_product.getText().toString();
    holder.quantity.setText(quant_items.get(position));

    quant = holder.quantity.getText().toString();
    holder.tv_id.setText(Integer.toString(ids.get(position)));


    id = holder.tv_id.getText().toString();
    id_final = Integer.parseInt(id);





    holder.image.setImageBitmap(loadImageFromStorage(list_images.get(position)));
    image_new = holder.image.toString();


    final View finalRowView1 = rowView;

            holder.quantity.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int after) {

                }

                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count) {



                }

                @Override
                public void afterTextChanged(Editable s) {
                    value = s.toString();
                    quant.replace(quant, value);
                    updateTable();

                    Toast.makeText(finalRowView1.getContext(), "Updating Table", Toast.LENGTH_SHORT).show();




                }


            });




    final View finalRowView = rowView;
    rowView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String name_item = ((TextView) finalRowView.findViewById(R.id.name_cart)).getText().toString();
            String price_item = ((TextView) finalRowView.findViewById(R.id.price_cart)).getText().toString();
            model_item = ((TextView) finalRowView.findViewById(R.id.model_cart)).getText().toString();

            Intent in = new Intent(context, AddCart_FullImage.class);
            in.putExtra("model", model_item);
            in.putExtra("name", name_item);
            in.putExtra("price", price_item);
            context.startActivity(in);
        }
    });
    return rowView;
}




private Bitmap loadImageFromStorage(String path) {

    try {
        File f = new File(path, "");
        f.canRead();
        b = BitmapFactory.decodeStream(new FileInputStream(f));
        return b;


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

    return null;
}


public void updateTable() {
    final DatabaseHandler db = new DatabaseHandler(context);

    SQLiteDatabase db1 = db.getWritableDatabase();
    try {
        db.updateContact(new Cart(id_final,name, price, image_new, model, product, value));
        Log.v("LOG", "After text change value db " + value);



    } catch (Exception e) {

    }



}
}

问题

当我尝试更新编辑文本值时，它会在db中更新，但它会再次更改为默认值＆＃34; 1＆＃34;。

我不确定我哪里出错了。

任何帮助都会非常棒。

感谢。

Answer 1

如果更改了数据，则需要通知适配器（并且需要使用新值更新list_name）。通知适配器的最简单方法是在更新数据后使用notifyDatasetChanged()。

Answer 2

每次系统想要重绘ListView时，它都会调用适配器的getView（...）方法。以下行设置您的数量EditText的值：

holder.quantity.setText(quant_items.get(position));

当用户更改EditText中的值时，您执行以下操作：

quant.replace(quant, value);
updateTable();

如您所见，适配器的数据源（quant_items）未更新。由于您正在从适配器中更新数据库，因此您只需更新quant_items ArrayList即可。它应该可以解决问题。

更改数据库值后，Listview未在baseadapter内更新

2 个答案: