Question

我是一个初学Android程序员，我正在尝试制作小费计算器。这是我迄今为止编写的代码。我有两个问题。首先，为什么我的计算按钮不起作用？第二个是，如果这段代码是干净的？或者我是在错误的轨道上？

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Fooi extends Activity implements OnClickListener {
    EditText etBill, etPers, etPerc;
    TextView tvTotal, tvTip, tvPerson;
    Button bCalc, bReset;

    double billamount = 0;
    double percentage = 0;
    double persons = 0;
    double tipamount = 0;
    double totaltopay = 0;
    double perperson = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fooi);

        Controls();
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.bCalculate:
            if (billamount == 0 | percentage == 0 | persons == 0) {
                // toast text
            } else {
                Calculate();
            }
            break;
        case R.id.bReset:
            etBill.setText("");
            etPerc.setText("");
            etPers.setText("");
            break;
        }
    }

    private void Calculate() {
        billamount = Double.parseDouble(etBill.getText().toString());
        percentage = Double.parseDouble(etPerc.getText().toString());
        persons = Double.parseDouble(etPers.getText().toString());

        tipamount = (billamount * percentage) / 100;
        totaltopay = billamount + tipamount;
        perperson = totaltopay / persons;

        tvTip.setText(Double.toString(tipamount));
        tvTotal.setText(Double.toString(totaltopay));
        tvPerson.setText(Double.toString(perperson));
    }

    private void Controls() {
        bCalc = (Button) findViewById(R.id.bCalculate);
        bReset = (Button) findViewById(R.id.bReset);
        bCalc.setOnClickListener(this);
        bReset.setOnClickListener(this);

        tvTotal = (TextView) findViewById(R.id.tvTotal);
        tvTip = (TextView) findViewById(R.id.tvBill);
        tvPerson = (TextView) findViewById(R.id.tvPerPerson);

        etBill = (EditText) findViewById(R.id.etBill);
        etPerc = (EditText) findViewById(R.id.etPercentage);
        etPers = (EditText) findViewById(R.id.etPerson);
    }
}

关于这行代码，我不确定。 if (billamount == 0 | percentage == 0 | persons == 0) { // toast text 我希望它只在三个EditTexts被填充时计算。有人可以告诉我，如果我错了吗？

提前致谢!!

Answer 1

代码写得很好，除了你的2件事： 1）你的if条款

if (billamount == 0 | percentage == 0 | persons == 0)

在条件之间

到“OR”，使用双管而不是单个管道，所以：

if (billamount == 0 || percentage == 0 || persons == 0)

2）在计算之前你没有从editTexts获取值... 将这些行（并添加空检查）移动到计算按钮上的onClick案例的开头：

 billamount = Double.parseDouble(etBill.getText().toString());
percentage = Double.parseDouble(etPerc.getText().toString());
persons = Double.parseDouble(etPers.getText().toString());

基本提示计算器Android Java

1 个答案: