Using an input string in a textbox

I am trying to have the user input a number, and then that number is used to populate a text field on a jform. However it keeps giving me errors. If I have the textfield call the str it gives me a numberformatexception, if I have it call the int variable it says it has to be a string...

public static String prePaidstr = "";
public stati开发者_StackOverflowc double prePaidint = 0;

prePaidstr = 
JOptionPane.showInputDialog("Enter any amount prepaid:");
prePaidint = Double.parseDouble(prePaidstr);

jTextField13.setText(InvoiceSelectionUI.prePaidstr)

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parseDouble converts a String into a Double, which is why it complains if you try to pass it a double.

A NumberFormatException is thrown when parseDouble is unable to successfully turn a String into a double; in this case it's because you're trying to parseDouble on an empty string. prePaidStr needs to contain something like "1.99" - e.g. something that, to a human, looks like a Double.

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nm - I fixed it, just had one of the variables switched around