多个else if多个文本输入的语句检查

Question

我有5个textedits的数字和一个按钮。 单击该按钮时，应用程序将根据哪个字段为空来计算不同的方程式。 但是，当我将多个字段留空时，应用程序不断崩溃，并出现以下错误：第一个if语句中的第一个double无效。

代码的想法

if (first field.getText().toString().equals("")) {...}
else if (second field.getText().toString().equals("")) {...}
else if (third field.getText().toString().equals("")) {...}
else if (fourth field.getText().toString().equals("")) {...}
else if (fifth.getText().toString().equals("")) {...}
else {...}

基本上，最后一个应该只是举杯祝酒，如果不是以上任何一项（2-5空，0空

真正的语法是这样的：

    calc.setOnClickListener(new OnClickListener() {         
            public void onClick(View v) {
                EditText fv = (EditText) findViewById(R.id.pv_fv);
                EditText pv = (EditText) findViewById(R.id.pv_pv);
                EditText r = (EditText) findViewById(R.id.pv_discountrate);
                EditText n = (EditText) findViewById(R.id.pv_periods);
                EditText t = (EditText) findViewById(R.id.pv_years);



                if (fv.getText().toString().equals("")) {
                    double r1 = Double.parseDouble(r.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double answer1 = pv1*(Math.pow(1+(r1/n1) ,n1*t1 ));
                    answer1 = (double)(Math.round(answer1*100))/100;
                    TextView answer = (TextView) findViewById(R.id.pv_answer);
                    answer.setText("The Future Value of the cash flow is: "+answer1);
                }

                else if (pv.getText().toString().equals("")) {
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double r1 = Double.parseDouble(r.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double answer1 = fv1/(Math.pow(1+(r1/n1) ,n1*t1 ));
                    answer1 = (double)(Math.round(answer1*100))/100;
                    TextView answer = (TextView) findViewById(R.id.pv_answer);
                    answer.setText("The Present Value of the cash flow is: "+answer1);                      
                }

                else if (r.getText().toString().equals("")){
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double answer1 = ( (Math.pow(fv1/pv1, 1/(n1*t1) ) ) -1)*n1 ;
                    answer1 = (double)(Math.round(answer1*100))/100;
                    TextView answer = (TextView) findViewById(R.id.pv_answer);
                    answer.setText("The discount rate / interest rate applied is: "+answer1);
                }

                else if (t.getText().toString().equals("")){
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double r1 = Double.parseDouble(r.getText().toString());
                    double answer1 = Math.log(fv1/pv1) / (n1* Math.log(1+(r1/n1) ) ) ;
                    answer1 = (double)(Math.round(answer1*100))/100;
                    TextView answer = (TextView) findViewById(R.id.pv_answer);
                    answer.setText("The number of years is: "+answer1);
                }

                else if(n.getText().toString().equals("")){
                    Toast errormsg = Toast.makeText(PresentValue.this, "Sorry but Number of Periods cannot be computed.", 5000);
                    errormsg.setGravity(Gravity.CENTER, 0, 0);
                    errormsg.show();
                }

                else {
                    Toast errormsg = Toast.makeText(PresentValue.this, "You either left too many fields empty or filled all of them.", 5000);
                    errormsg.setGravity(Gravity.CENTER, 0, 0);
                    errormsg.show();
                }

            }           
        });

有什么问题的想法吗？

Answer 1

假设您只有这五个字段-仅当所有字段都不为空时， else语句才可访问。

如果只有一个为空，它将被相关的if语句捕获-在此方面可以正常工作。
如果两个或两个以上的矿石都空了-它只会被捕获一次，在第一个条件适用的情况下-这似乎不是您想要的。
如果没有一个为空-尽管没有一个为空，则将到达else语句-这显然是您想要的。

一种替代方法可能是不使用else if语句，而仅if s并计算故障数时使用。 如果它更高，则为1-多个字段为空。 如果为0-没有字段为空。 是否可以应用当然取决于每个语句的块的实际内容。

Answer 2

将名称或对字段的引用放入List或Set 。 然后，您可以轻松地取回所需的空文件。

和

if (emptyFieldSet.size() > 1) {
    toast that says "error multiples are empty"
}

比起if s后面的else语句更具可读性。

Answer 3

这就是我解决的方法。 但是似乎真的...闷。 有没有办法让它看起来更隐蔽？

//clickhandler
        calc.setOnClickListener(new OnClickListener() {         
            public void onClick(View v) {
                EditText fv = (EditText) findViewById(R.id.pv_fv);
                EditText pv = (EditText) findViewById(R.id.pv_pv);
                EditText r = (EditText) findViewById(R.id.pv_discountrate);
                EditText n = (EditText) findViewById(R.id.pv_periods);
                EditText t = (EditText) findViewById(R.id.pv_years);
                TextView answer = (TextView) findViewById(R.id.pv_answer);
                int filledfields = 0;

                if (fv.getText().toString().equals("")){
                    filledfields ++;
                }
                if (pv.getText().toString().equals("")) {
                    filledfields ++;
                }
                if (r.getText().toString().equals("")) {
                    filledfields ++;
                }
                if (t.getText().toString().equals("")) {
                    filledfields ++;
                }
                if (n.getText().toString().equals("")) {
                    filledfields ++;
                }

                if (filledfields > 1){
                    Toast errormsg = Toast.makeText(PresentValue.this, "Sorry but you left more than one field empty.", 5000);
                    errormsg.setGravity(Gravity.CENTER, 0, 0);
                    errormsg.show();
                }

                else if (fv.getText().toString().equals("")) {
                    double r1 = Double.parseDouble(r.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double answer1 = pv1*(Math.pow(1+(r1/n1) ,n1*t1 ));
                    answer1 = (double)(Math.round(answer1*100))/100;

                    answer.setText("The Future Value of the cash flow is: "+answer1);
                }

                else if (pv.getText().toString().equals("")) {
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double r1 = Double.parseDouble(r.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double answer1 = fv1/(Math.pow(1+(r1/n1) ,n1*t1 ));
                    answer1 = (double)(Math.round(answer1*100))/100;

                    answer.setText("The Present Value of the cash flow is: "+answer1);                      
                }

                else if (r.getText().toString().equals("")){
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double t1 = Double.parseDouble(t.getText().toString());
                    double answer1 = ( (Math.pow(fv1/pv1, 1/(n1*t1) ) ) -1)*n1 ;
                    answer1 = (double)(Math.round(answer1*100))/100;

                    answer.setText("The discount rate / interest rate applied is: "+answer1);
                }

                else if (t.getText().toString().equals("")){
                    double fv1 = Double.parseDouble(fv.getText().toString());
                    double pv1 = Double.parseDouble(pv.getText().toString());
                    double n1 = Double.parseDouble(n.getText().toString());
                    double r1 = Double.parseDouble(r.getText().toString());
                    double answer1 = Math.log(fv1/pv1) / (n1* Math.log(1+(r1/n1) ) ) ;
                    answer1 = (double)(Math.round(answer1*100))/100;

                    answer.setText("The number of years is: "+answer1);
                }

                else if(n.getText().toString().equals("")){
                    Toast errormsg = Toast.makeText(PresentValue.this, "Sorry but Number of Periods cannot be computed.", 5000);
                    errormsg.setGravity(Gravity.CENTER, 0, 0);
                    errormsg.show();
                }

                else {
                    Toast errormsg = Toast.makeText(PresentValue.this, "You either left too many fields empty or filled all of them.", 5000);
                    errormsg.setGravity(Gravity.CENTER, 0, 0);
                    errormsg.show();
                }

            }           
        });
        //clickhandler end