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我在下面这样编码。但它不起作用。我需要根据其中两个字段的输入来执行简单的加法和简单的减法......问题结束......

我需要编写此文本，因为如果细节不够，代码不仅仅是细节，我无法提出问题。所以我只是输入这个来问我的问题。忽略它并查看下面的代码。谢谢

Java 代码：

package com.test.easycount;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements TextWatcher {

    EditText num1, num2, sum;
    int fnumber, snumber, total;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        num1 = (EditText) findViewById(R.id.num1);
        num2 = (EditText) findViewById(R.id.num2);
        sum = (EditText) findViewById(R.id.sum);

        num1.addTextChangedListener(this);
        num2.addTextChangedListener(this);
        sum.addTextChangedListener(this);

        fnumber = Integer.parseInt(num1.getText().toString());
        snumber = Integer.parseInt(num2.getText().toString());
        total = Integer.parseInt(sum.getText().toString());
    }

    @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) {

        if (num1.getText().toString().length() > 0 && num2.getText().toString().length() > 0) {

            total = fnumber + snumber;
            sum.setText(Integer.toString(total));

        } else if (num1.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {

            snumber = total - fnumber;
            num2.setText(Integer.toString(snumber));
        } else if (num2.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {

            fnumber = total - snumber;
            num1.setText(Integer.toString(fnumber));
        }
    }
}

请帮我做到这一点....

4

2 回答 2

0

删除初始化变量并将它们粘贴到afterTextChanged 

  @Override
            public void afterTextChanged(Editable s) {

        try {
             fnumber = Integer.parseInt(num1.getText().toString());
        } catch (NumberFormatException e) {
            fnumber = 0;
            Log.e("numberFormat", e.toString());
        }

        try {
            snumber = Integer.parseInt(num2.getText().toString());
        } catch (NumberFormatException e) {
            snumber = 0;
            Log.e("numberFormat", e.toString());
        }

        try {
            total = Integer.parseInt(sum.getText().toString());
        } catch (NumberFormatException e) {
            total = 0;
            Log.e("numberFormat", e.toString());
        }

      if (num1.getText().toString().length() > 0 && num2.getText().toString().length() > 0) {

                    total = fnumber + snumber;
                    sum.setText(Integer.toString(total));

                } else if (num1.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {

                    snumber = total - fnumber;
                    num2.setText(Integer.toString(snumber));
                } else if (num2.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {

                    fnumber = total - snumber;
                    num1.setText(Integer.toString(fnumber));
                }
            }
于 2017-08-20T05:03:20.147 回答
0

您必须在 textWatcher 中计算 fnumber、snumber、total：

认为：

    @Override
    public void afterTextChanged(Editable s) {

        if (num1.getText().toString().length() > 0 && num2.getText().toString().length() > 0) {
            fnumber = Integer.parseInt(num1.getText().toString());
            snumber = Integer.parseInt(num2.getText().toString());
            total = fnumber + snumber;
            sum.setText(Integer.toString(total));

        } else if (num1.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {
            fnumber = Integer.parseInt(num1.getText().toString());
            total = Integer.parseInt(sum.getText().toString());
            snumber = total - fnumber;
            num2.setText(Integer.toString(snumber));

        } else if (num2.getText().toString().length() > 0 && sum.getText().toString().length() > 0) {
            snumber = Integer.parseInt(num2.getText().toString());
            total = Integer.parseInt(sum.getText().toString());
            fnumber = total - snumber;
            num1.setText(Integer.toString(fnumber));
        }
}

并从 onCreate 中移除 fnumber、snumber、total 初始化。

为了便于计算，最好为每个编辑文本使用单独的 textWatcher：

前任：

num1.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void afterTextChanged(Editable editable) {

            }
        });
于 2017-08-20T05:05:14.797 回答