我在CardView中有一个按钮，它代表RecycleView的项目。我已经成功处理了ViewHolder类中的click事件，但我需要在MainActivity上调用函数，如何使用下面的代码实现它？
我的代码如下
ShopItemRecyclerViewAdapter.java
public class ShopItemRecyclerViewAdapter extends RecyclerView.Adapter<ShopItemRecyclerViewAdapter.ListItemViewHolder> {
static ArrayList<ShopListItemModel> list;
LayoutInflater inflater;
public ShopItemRecyclerViewAdapter(ArrayList<ShopListItemModel> list, Context context){
inflater = LayoutInflater.from(context);
this.list = list;
}
public ListItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.list_item, parent , false);
ListItemViewHolder vh = new ListItemViewHolder(view);
return vh;
}
public void onBindViewHolder(ListItemViewHolder holder, int position) {
ShopListItemModel current = list.get(position);
holder.name.setText(current.getName());
holder.price.setText(String.valueOf(current.getPrice()));
}
public int getItemCount() {
return list.size();
}
public static class ListItemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
CardView cv;
TextView name;
TextView price;
ImageButton btnDelete;
ListItemViewHolder(final View itemView) {
super(itemView);
cv = (CardView)itemView.findViewById(R.id.cvShopListItem);
name = (TextView)itemView.findViewById(R.id.name);
price = (TextView)itemView.findViewById(R.id.price);
btnDelete = (ImageButton)itemView.findViewById(R.id.btnDeleteItem);
itemView.setOnClickListener(this);
btnDelete.setOnClickListener(this);
}
@Override
public void onClick(View v) {
//here i can handle the click but i think i need to use it in the main activity
}
}
}
MainActivity.java（跳过无关紧要的代码）
public class ShopCartScreen extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
RecyclerView cartItems; //recycler to hold the cart list
ArrayList<ShopListItemModel> list = new ArrayList<ShopListItemModel>();
ShopItemRecyclerViewAdapter adapter;
GetShopingCartList getShopingCartList; ////instance of network operation class to retrieve shop cart items list from server data base
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.shop_carts_list);
cartItems = (RecyclerView) findViewById(R.id.newListItem);
cartItems.setHasFixedSize(true);
LinearLayoutManager llm = new LinearLayoutManager(this);
llm.setOrientation(LinearLayoutManager.VERTICAL);
cartItems.setLayoutManager(llm)
}
public void bindData(int listNumber) {
getShopingCartList = new GetShopingCartList(this, list, adapter, cartItems, listNumber, totalPrice);
getShopingCartList.execute("link to query which returns json object");
}
}
用于网络操作的GetShopingCartList.java
public class GetShopingCartList extends AsyncTask<String, String, ArrayList<ShopListItemModel>> {
private ArrayList<ShopListItemModel> shopCartItemList;
Context context;
RecyclerView items;
ShopItemRecyclerViewAdapter adapter;
int listNumber;
public GetShopingCartList(Context context, ArrayList<ShopListItemModel> shopCartItemList, ShopItemRecyclerViewAdapter adapter,
RecyclerView items ,int listNumber) {
this.context = context;
this.shopCartItemList = shopCartItemList;
this.adapter = adapter;
this.items = items;
this.listNumber = listNumber;
}
protected ArrayList<ShopListItemModel> doInBackground(String... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
shopCartItemList = new ArrayList<ShopListItemModel>();
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line);
}
String finalJson = buffer.toString();
JSONObject parentObject = new JSONObject(finalJson);
JSONArray parentArray = parentObject.getJSONArray("result");
for (int i = 0; i < parentArray.length(); i++) {
JSONObject finalObject = parentArray.getJSONObject(i);//get the cuttent json object which is representaion of shop cart model object
String name = finalObject.getString("name");
String price = finalObject.getString("price");
Double d = Double.parseDouble(price);
ShopListItemModel item = new ShopListItemModel(name, d);
shopCartItemList.add(item);//adds the shopcart to the list of shop carts model
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return shopCartItemList;
}
protected void onPostExecute(ArrayList<ShopListItemModel> s) {
super.onPostExecute(s);
adapter = new ShopItemRecyclerViewAdapter(shopCartItemList, context);
items.setAdapter(adapter);
}
public ArrayList<ShopListItemModel> getList() {
return shopCartItemList;
}
}
答案 0 :(得分：1)
在ShopCartScreen.java中实现一个方法，然后可以使用适配器内的context对象。
((ShopCartScreen)context).methodImplemented(ShopListItemModel model)
//add this code inside onClick event of the button
答案 1 :(得分：-1)
好吧这是我的解决方案，如果有人需要它（我在主要活动中合并2个方法/ 1，在回收器适配器中合并1个）：
在我的回收器适配器中添加了这个删除方法：
//delete the item from the recycler Immediately for user interaction
public void delete(int position){
list.remove(position);
notifyItemRemoved(position);
}
在我的ViewHolder类中：
ListItemViewHolder(final View itemView) {
super(itemView);
cv = (CardView)itemView.findViewById(R.id.cvShopListItem);
name = (TextView)itemView.findViewById(R.id.name);
price = (TextView)itemView.findViewById(R.id.price);
btnDelete = (ImageButton)itemView.findViewById(R.id.btnDeleteItem);
itemView.setOnClickListener(this);
btnDelete.setOnClickListener(this);
}
@Override
public void onClick(View v) {
((ShopCartScreen)context).deleteItem(getPosition());//calls method in main activity
delete(getPosition());
}
并在主要活动中：
public void deleteItem(int postion){
list = getShopingCartList.getList();
ShopListItemModel tmp = list.get(postion);
tmp.getName(); //gets the item name to remove
shopCartModel.getNumber(); //gets the cart number for deleting the item for the correct cart
new DeleteCartItem(this , shopCartModel , tmp).execute(); //remove the item from the data base
}