Question

我正在尝试获取用户输入的数字，并使用一些指定的值对其进行多次输入。我无法看到我犯错误的地方，我的应用程序一直在崩溃。我甚至无法运行它。

MainActivity.java

public abstract class MainActivity extends AppCompatActivity implements OnItemSelectedListener {

    Button calculateBtn;
    EditText userEcts;
    TextView summary;
    int price = 200;

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

        userEcts = (EditText) findViewById(R.id.ects_input);
        summary = (TextView) findViewById(R.id.text_summary);

        calculateBtn = (Button) findViewById(R.id.calculate);
        calculateBtn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                //When the button is clicked, call the calculate method.
                calculate();
            }
        });
    }

    public void calculate() {
        //gets entered text from the EditText,and convert to integers.
        Double ects = Double.parseDouble(userEcts.getText().toString());
        //do the calculation
        Double calculatedPrice = ects * price;
        //set the value to the TextView, to display on screen.
        summary.setText("Ukupno za platit: " + Double.toString(calculatedPrice) + "kn");
    }
}

Answer 1

您正在实施OnItemSelectedListener

change OnItemSelectedListener to View.OnClickListener

Answer 2

你应该这样做：

summary.setText("Ukupno za platit: " + calculatedPrice + "kn");

String + Double = String

Answer 3

我个人建议你在解析一个字符串之前在compute方法上放一个像这样的检查，因为空字符串在解析它时也会导致崩溃：

  public void calculate() {
        //Put this empty check to prevent crash while parsing empty string.
      if (!TextUtils.isEmpty(userEcts.getText.toString())){
          Double ects = Double.parseDouble(userEcts.getText().toString());
          //do the calculation
          Double calculatedPrice = ects * price;
          //set the value to the TextView, to display on screen.
          summary.setText("Ukupno za platit: " + Double.toString(calculatedPrice) + "kn");
      }

    }

希望这有帮助。

Answer 4

现在可以使用...在现有代码中添加了此代码

@Override
public void onClick(View v) {
    calculate();
}

非常感谢：）

来自EditText的多个号码，其分配的号码为Android

4 个答案: