java - 警报 Dialog.Builder(??)

Question

我正在尝试为用户按下卡片 View 以将其删除时制作一个警报对话框。这是在我的 ProductAdapter 代码中

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(????);

我会在括号中放什么？？？？我查看了该站点上的示例，我看到的示例在括号内使用了 ActivityName.this。但是，此代码位于 ProductAdapter 代码中，我无法使用 ProductAdapter.this。 (我的主要 Activity 称为 create.java fyi)

那里面会放什么呢？谢谢

更新

public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductViewHolder> {

    private Map<Integer, Integer> mSpinnerSelectedItem = new HashMap<Integer, Integer>();





    //this context we will use to inflate the layout
    private Context mCtx;
    private SearchableSpinner spinner;

    //we are storing all the products in a list
    private List<Product> productList;

    private Activity create;

    public  ProductAdapter(Activity activity){
        create = activity;
    }






    //getting the context and product list with constructor
    public  ProductAdapter(Activity activity, List<Product> productList) {
        this.mCtx = mCtx;
        create = activity;
        this.productList = productList;
    }

    @Override
    public ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //inflating and returning our view holder
        LayoutInflater inflater = LayoutInflater.from(mCtx);
        View view = inflater.inflate(R.layout.layout_products, null);
        return new ProductViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ProductViewHolder holder, final int position) {
        // //getting the product of the specified position


        ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(mCtx, R.layout.item_spinner_layout,
                Product.getSpinnerItemsList());
        spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        holder.spinner.setAdapter(spinnerArrayAdapter);

        holder.spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int mPosition, long id) {
                mSpinnerSelectedItem.put(position, mPosition);

                TextView mTextView = view.findViewById(R.id.mSpinnerText);
                Toast.makeText(mCtx, "Selected Item: " + mTextView.getText().toString(), Toast.LENGTH_LONG).show();
                Log.e("***************", "Selected Item: " + mTextView.getText().toString());


            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });


        //binding the data with the viewholder views
        if (mSpinnerSelectedItem.containsKey(position)) {
            holder.spinner.setSelection(mSpinnerSelectedItem.get(position));
        }


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


                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(create);


                // set title
                alertDialogBuilder.setTitle("Delete Item");

                // set dialog message
                alertDialogBuilder
                        .setMessage("Are you sure you want to delete this item?")
                        .setCancelable(false)
                        .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                // if this button is clicked, close
                                // current activity

                                productList.remove(position);
                                notifyItemRemoved(position);



                            }
                        })
                        .setNegativeButton("No", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                // if this button is clicked, just close
                                // the dialog box and do nothing
                                dialog.cancel();
                            }
                        });

                // create alert dialog
                AlertDialog alertDialog = alertDialogBuilder.create();

                // show it
                alertDialog.show();









            }
        });
    }






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





    class ProductViewHolder extends RecyclerView.ViewHolder {

        SearchableSpinner spinner;
        EditText editText;
        TextView textView5;
        CheckBox checkBox;
        LinearLayout linearLayout;
        View rootView;




        public ProductViewHolder(View itemView) {
            super(itemView);

            spinner = itemView.findViewById(R.id.spinner);
            editText = itemView.findViewById(R.id.editText);
            textView5 = itemView.findViewById(R.id.textView5);
            checkBox = itemView.findViewById(R.id.checkBox);
            rootView = itemView.findViewById(R.id.linearLayout);

        }

        public View getView() {
            return rootView;
        }

    }





}

Answer 1

尽管 AlertDialog.Builder() 在其参数中接受一个 Context 引用，但最好传递一个 Activity 引用给它，而不是applicationContext 因为潜在的主题和窗口附件问题。因此，将 Activity 引用传递给您的适配器并使用它来构建 AlertDialog。

public class ProductAdapter extends SomeAdapter {

    private Activity create;

    public  ProductAdapter(Activity activity, List<Product> productList) {
        create = activity;
        this.productList = productList;
    }

    private void showAlertDialog(){
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(create);
        // ...
        alertDialogBuilder.create().show();
    }

}