Question

嘿，我是Android Studio的新手，我一直在尝试制作一个计算器应用程序，该应用程序最初可以运行，我记得在“取消”按钮中进行过更改，此后无论我按哪个按钮，结果始终为NaN，香港专业教育学院尝试过，只是想不通。请告诉我原因是什么？代码如下。

    String str="\0";
Character operator;
Double operand1=Double.NaN;
Double operand2;
EditText numberview;

 public void compute()
 {
     final EditText numberview = (EditText) findViewById(R.id.editText);
     if(operand1!=Double.NaN)
     {
          operand2=Double.parseDouble(numberview.getText().toString());
         switch(operator)
         {
             case '+': operand1=operand1+operand2; break;
             case '-': operand1=operand1-operand2; break;
             case '*': operand1=operand1*operand2; break;
             case '/': operand1=operand1/operand2; break;
             case '=': break;
              default: break;
         }

     }
     else
     {
          operand1=Double.parseDouble(numberview.getText().toString());
     }
 }
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final EditText numberview = (EditText) findViewById(R.id.editText);
    Button number1 = (Button) findViewById(R.id.button1);
    Button number2 = (Button) findViewById(R.id.button2);
    Button number3 = (Button) findViewById(R.id.button3);
    Button number4 = (Button) findViewById(R.id.button4);
    Button number5 = (Button) findViewById(R.id.button5);
    Button number6 = (Button) findViewById(R.id.button6);
    Button number7 = (Button) findViewById(R.id.button7);
    Button number8 = (Button) findViewById(R.id.button8);
    Button number9 = (Button) findViewById(R.id.button9);
    Button number0 = (Button) findViewById(R.id.button10);
    Button numbercancel = (Button) findViewById(R.id.button11);
    Button numberplus = (Button) findViewById(R.id.button12);
    Button numberminus = (Button) findViewById(R.id.button13);
    Button numberdivide = (Button) findViewById(R.id.button15);
    Button numbermultiply = (Button) findViewById(R.id.button14);
    Button numberequal = (Button) findViewById(R.id.button17);

    number1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "1";
            numberview.setText(str);


        }
    });
    number2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "2";
            numberview.setText(str);
        }
    });
    number3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "3";
            numberview.setText(str);
        }
    });
    number4.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "4";
            numberview.setText(str);


        }
    });
    number5.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "5";
            numberview.setText(str);


        }
    });
    number6.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "6";
            numberview.setText(str);


        }
    });
    number7.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "7";
            numberview.setText(str);

        }
    });
    number8.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "8";
            numberview.setText(str);


        }
    });
    number9.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "9";
            numberview.setText(str);


        }
    });
    number0.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = numberview.getText().toString() + "0";
            numberview.setText(str);

        }
    });
    numbercancel.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            str = "";
            numberview.setText("");
            operand1=Double.NaN;


        }
    });
    numberplus.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            operator = '+';
            compute();
            str="";
            numberview.setText("");




        }
    });
    numberminus.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            operator = '-';
            compute();
            str="";
            numberview.setText("");



        }
    });
    numberdivide.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            operator = '/';
            compute();
            str="";
            numberview.setText("");




        }
    });
    numbermultiply.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            operator = '*';
            compute();
            str="";
            numberview.setText("");




        }
    });
    numberequal.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            compute();
            numberview.setText(String.valueOf(operand1));

        }

    });


}

Answer 1

我找到了解决方案的人，我对NaN进行了一些搜索，我只需要使用Double.IsNan（operand1）函数而不是我使用的函数。干杯。

计算器应用程序出现问题

1 个答案: