Question

我制作了一个折扣应用程序，带有2个输入和一个按钮来计算结果。

此折扣应用实现了一个片段来实现tabview滑动

然而，当2 edittext或1 edittext为空时按下按钮时应用程序崩溃。

当editext为空但我没有工作时，我曾使用toast来显示。

package com.ywapp.yw.discountcal;

import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


/**
 * A simple {@link Fragment} subclass.
 */
public class Tab1 extends Fragment {

    // Variable Declaration
    EditText price_box_field;
    EditText discount_box_field;
    TextView result_text_field;
    Button cal_btn;

    double price,discount,result,save;


    public Tab1() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view= inflater.inflate(R.layout.fragment_tab1, container, false);


        final EditText price_box_field=(EditText)view.findViewById(R.id.price_box);
        final EditText discount_box_field=(EditText)view.findViewById(R.id.discount_price_box);

        final TextView result_text_field=(TextView)view.findViewById(R.id.result_text);
        Button cal_btn=(Button)view.findViewById(R.id.cal_btn);



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


                price=Double.parseDouble(price_box_field.getText().toString());
                discount=Double.parseDouble(discount_box_field.getText().toString());

                if(price_box_field.getText().toString().isEmpty()) {
                    Toast.makeText(getActivity(),"please enter something in text box",Toast.LENGTH_LONG).show();
                }

                if(discount_box_field.getText().toString().isEmpty()) {
                    Toast.makeText(getActivity(),"please enter something in text box",Toast.LENGTH_LONG).show();
                }


                result=(price-((price*discount)/100));
                save=price-result;

                String result_word="After Discount: RM ";
                String result_set=result_word+String.format("%.2f", result)+"\nYou saved RM "+String.format("%.2f", save);
                result_text_field.setText(result_set);


            }
        });
        return view;
    }
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

Answer 1

您必须在解析值之前添加检查：

cal_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if(price_box_field.getText().length()==0) {
                Toast.makeText(getActivity(),"please enter something in text box",Toast.LENGTH_LONG).show();
                return; //to stop the method from parsing empty values
            }

            if(discount_box_field.getText().length()==0) {
                Toast.makeText(getActivity(),"please enter something in text box",Toast.LENGTH_LONG).show();
                return; //to stop the method from parsing empty values
            }


            price=Double.parseDouble(price_box_field.getText().toString());
            discount=Double.parseDouble(discount_box_field.getText().toString());




            result=(price-((price*discount)/100));
            save=price-result;

            String result_word="After Discount: RM ";
            String result_set=result_word+String.format("%.2f", result)+"\nYou saved RM "+String.format("%.2f", save);
            result_text_field.setText(result_set);


        }
    });

当多个EditTexts为空时，按钮单击会崩溃我的应用程序

1 个答案: