Question

    final EditText number1 = (EditText) findViewById(R.id.editText1);
    final EditText number2 = (EditText) findViewById(R.id.editText2);
    final TextView result =(TextView) findViewById(R.id.textView3);

    Button calculate = (Button) findViewById(new View.OnClickListener() {

我做错了什么？

    public void onClick(View v) {

number1和数字要转换为double但我得到＆＃34;不能在原始类型double＆＃34;上调用getText（）错误

    double number1 = Double.parseDouble(number1.getText().toString());//error

    double number2 = Double.parseDouble(number2.getText().toString());error         

        result.setText(String.valueOf(number1*number2));

Answer 1

更改此

 final EditText number1 = (EditText) findViewById(R.id.editText1);
 final EditText number2 = (EditText) findViewById(R.id.editText2);

到

final EditText num1 = (EditText) findViewById(R.id.editText1);
final EditText num2 = (EditText) findViewById(R.id.editText2);

并使用

double number1 = Double.parseDouble(num1.getText().toString());
double number2 = Double.parseDouble(num2.getText().toString());

您有EditText numberr1和double number1

使用MainActivity.this.varaiblename引用在onClick之外声明和初始化的变量。

你可以去查看

What is variable shadowing used for in a Java class?

找到更好的解释@

question about variable scope and shadowing in java

还有试试

try
{
final EditText num1 = (EditText) findViewById(R.id.editText1);
final EditText num2 = (EditText) findViewById(R.id.editText2);
}catch(NumberFormatException e){
    e.printStacktrace();
}

如果字符串不包含可解析的double，则

抛出NumberFormatException。

Answer 2

你不能拥有同名的变量/实例。因为您正在尝试创建具有相同名称的EditText和double的实例...这就是为什么它会给您错误。

现在，将您的变量名称double更改为如下...

double number1 = Double.parseDouble(number1.getText().toString());

double number2 = Double.parseDouble(number2.getText().toString());         

result.setText(String.valueOf(number1*number2));

于...

double num1 = Double.parseDouble(number1.getText().toString());

double num2 = Double.parseDouble(number2.getText().toString());        

result.setText(String.valueOf(num1*num2));

Answer 3

更改

double number1 = Double.parseDouble(number1.getText().toString());//error

double number2 = Double.parseDouble(number2.getText().toString());error

到

double number1 = Double.parseDouble(YourActivity.this.number1.getText().toString());//error

double number2 = Double.parseDouble(YourActivity.this.number2.getText().toString());error

您还需要制作两个EditText个全局变量。您为EditText和double指定了相同的名称，因此在方法中创建的变量会影响EditText

Answer 4

试试这个..

final EditText editText1_number1 = (EditText) findViewById(R.id.editText1);
final EditText editText2_number2 = (EditText) findViewById(R.id.editText2);

更改您的EditText名称并尝试。

double number1 = Double.parseDouble(editText1_number1.getText().toString());
double number2 = Double.parseDouble(editText2_number2.getText().toString());

Answer 5

使用

double num1 = Double.parseDouble(number1.getText().toString());

double num2 = Double.parseDouble(number2.getText().toString());        

result.setText(String.valueOf(num1*num2));

而不是

double number1 = Double.parseDouble(number1.getText().toString());

double number2 = Double.parseDouble(number2.getText().toString());         

result.setText(String.valueOf(number1*number2));

因为你已经

了

final EditText number1 = (EditText) findViewById(R.id.editText1);
    final EditText number2 = (EditText) findViewById(R.id.editText2);

你错误地使用了number1和number2 !!

我做错了什么？错误是无法在基本类型double上调用getText（）

5 个答案: