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Android

Posted by Robert Kendall
Robert Kendall
1,287 Points

Getting Double from String

Building a simple app which pulls data from edittext boxes, performs calculation and outputs an answer.

trying to pull data as edit text, then convert to string, then to double. Seems like there should be a more direct way, but this seems like it should technically work. 

public class MainPage extends Activity {
    private EditText mbalanceEditText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_page);
        mbalanceEditText = (EditText)findViewById(R.id.balanceEditText);
        String bal = mbalanceEditText.getText().toString();
        Double mbalDouble = Double.parseDouble(bal);

When I run, I receive a fatal error:
Caused by: java.lang.NumberFormatException: Invalid double: "" at java.lang.StringToReal.invalidReal(StringToReal.java:63) at java.lang.StringToReal.parseDouble(StringToReal.java:248) at java.lang.Double.parseDouble(Double.java:295)

Is it a syntax error, or something else? Also, is there a more convenient way to do this?

1 Answer

James Simshaw
James Simshaw
28,738 Points
James Simshaw
James Simshaw
28,738 Points

Hello,

Right now, you are trying to get the data value from the EditText right when you start your Activity. It looks like you are getting a default value of the empty string which parseDouble is throwing an Exception on since it isn't a number. More likely, what you would want to do is have a button that you push and then get the string and parse it after the button is pressed. If you need more assistance please let us know and we can provide further assistance.