[英]How to access ArrayList from custom adapter class, when the ArrayList is stored in a class that extends Application
我創建了一個擴展Application的類,該應用程序存儲帶有多個值的ArrayList。 該類用於在整個應用程序中存儲值,因此我可以在需要時訪問它們。
但是,由於出現以下錯誤,因此無法在自定義適配器類中調用“ getApplicationContext()”:
錯誤:找不到符號方法getApplicationContext()
如果我是正確的,那是因為自定義適配器類沒有擴展AppCompatActivity。
有人知道可以解決這個問題嗎? 最終,我試圖從存儲的ArrayList創建一個ListView。
我的代碼如下。
public class CartListAdapter extends ArrayAdapter<Product> {
private ArrayList<Product> products;
public CartListAdapter(Context context, int textViewResourceId, ArrayList<Product> products ) {
super(context, textViewResourceId, products);
this.products=products;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.activity_cart_row_item, parent, false);
final Global globalVariables = (Global) getApplicationContext();
//get product stored in array that exists in Application class
Product p = globalVariables.getMyProducts(position);
TextView name = (TextView) row.findViewById(R.id.cart_product_name);
TextView price = (TextView) row.findViewById(R.id.cart_product_price);
TextView quantity = (TextView) row.findViewById(R.id.cart_quantity_text);
TextView type = (TextView) row.findViewById(R.id.cart_type);
TextView option = (TextView) row.findViewById(R.id.cart_option);
name.setText(p.getProductName());
price.setText(p.getProductPrice());
quantity.setText(p.getProductQuantity());
type.setText(p.getProductType());
option.setText(p.getProductOption());
return row;
}
}
public class Global extends Application {
private ArrayList <Product> myProducts = new ArrayList<>();
private Cart cart;
public Cart getCart() {
return cart;
}
public void setCart(Cart cart) {
this.cart = cart;
}
public Product getMyProducts(int position) {
return myProducts.get(position);
}
public void addMyProducts(Product product) {
myProducts.add(product);
}
public int getMyProductsSize (){
return myProducts.size();
}
}
假設您在ArrayAdapter
使用它,而不是使用getApplicationContext()
,應該使用getContext().getApplicationContext()
。
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