GWT - convert string to float 2 decimal places

Question

I have some string values that I need to convert to float while preserving two decimal places. I am using GWT so all the examples I try dont work in GWT 2.7

String value = "00.00";
String value2 = "-34.90";
String value3 = "3.45";

How can I convert string to float with 2 decimal places in GWT?

Answer 1

GWT is a framework and you don't "convert" strings to floats in GWT but in Java.

As already stated in comments, you can't ask for a specific precision in float or double . You also can't trust that their String representation is their actual value...

If you really need only two decimals to represent a number, I suggest you use an int that gets the value times 100, then perform the simple arithmetics anywhere you need. You can wrap it in a Number class:

class TwoDecimal extends Number {
    protected int val;

    public TwoDecimal(double val) {
        this.val = (int)Math.round(100 * val);
    }

    @Override
    public double toDouble() {
        return val / 100.0;
    }

    // Implement other abstract toXXX() methods

    @Override
    public String toString() {
        return (val / 100) + "." + (val % 100);
    }
}

Also keep in mind that an int might not be able to store the span a double covers, so you should adapt it to your use-case.