How to convert a string to long number with 3 decimals in Android using NumberPicker

Question

I have 4 number pickers and I concat as string the 4 numbers How I am going to convert this into long I using the following

String decimals=units2.concat(units3).concat(units4);
String units = units1;
String finalGrade = units1+decimals;
long Grade = Long.valueOf(finalGrade).longValue();
NumberFormat f = new DecimalFormat("000");
txtGrades.setText(f.format(Grade));

But I get instead of 1.234 a 1234

Kelevandos · Accepted Answer · 2016-05-19T08:43:48.613

0

Just do something like this:

String resultAsString = String.valueOf(units1) 
    + "." 
    + String.valueOf(units2) + 
    + String.valueOf(units3) + 
    + String.valueOf(units4);
Double result = Double.valueOf(resultAsString);

Or you could update this line in your code:

String finalGrade = units1+decimals;

To this:

String finalGrade = units1 + "." + decimals;

This can be further optimised with StringBuilder and such, but I wanted to present the general idea :-)

Also, from experience, doing stuff like this using Strings ensures you get frontal 0s right (which is important for stuff like numeric passwords), as using numerical calculations will usually result in the frontal 0s being tossed away.

edited May 19 '16 at 08:43

answered May 19 '16 at 08:24

Kelevandos

7,024
2
29
46

without decimal format? – Miaoulis Nikos May 19 '16 at 08:27
Ah, damn, I misread the question! :O just a sec, I will update – Kelevandos May 19 '16 at 08:27
Here you go. I updated my solution and gave an example how your can be edited :-) – Kelevandos May 19 '16 at 08:30
Are you trying to parse a String "1.234" in Long ? Good luck ;) You have a decimal value here. – AxelH May 19 '16 at 08:33
String finalGrade = units1 + "." + decimals; is not working I ve tried it first – Miaoulis Nikos May 19 '16 at 08:34
@AxelH - Thanks for pointing that out, I automatically assumed OP got that right... Updating the answer – Kelevandos May 19 '16 at 08:43

How to convert a string to long number with 3 decimals in Android using NumberPicker

1 Answers1