Working with numbers in android

Question

I am new to android development. I am creating an app in which attendance percentage needs to be calculated. I want to calculate the attendance percentage and place that data in the EDIT TEXT field but when I run the application the data is not calculated instead I have to insert it manually. Please help me out with this. TIA :) Here is my code

float percentage = ((attendClasses / totClasses) * 100);
                        str_percentage = String.valueOf(percentage);
                        ed_percentage.setText(str_percentage);

                        // To insert candidate values into the database
                        boolean result = mySQLiteAdapter.onInsertAttendance(
                                studId, subjId, str_totclasses,
                                str_attendedclasses, str_percentage);

Please first explain what exactly the problem is, otherwise no one can help you... — Xaver Kapeller, May 04 '15 at 18:15
I want the percentage to be calculated and placed in edit text field but the percentage is not showing when I am running the app — user3530830, May 04 '15 at 18:15
I am able to see the EditText but there I need to insert value manually. I want it to be calculated and placed in that field — user3530830, May 04 '15 at 18:18
If totClasses is an int, cast it to float '(float)totClasses' — Marcio Covre, May 04 '15 at 18:27
If `attendClasses` and `totClasses` are `int`s, then Java integer division will give you zero when you divide them, assuming `attendClasses` is smaller than `totClasses`. — GriffeyDog, May 04 '15 at 18:30
@user3530830 'is not showing' is very different from 'is 0.0', don't you think? You could have a correct answer within minutes, if you had explained this correctly. Please be careful the next time. — isnot2bad, May 04 '15 at 18:42

Dhaval Patel · Accepted Answer · 2015-05-04T18:29:58.127

1

Change float percentage = ((attendClasses / totClasses) * 100); to float percentage = ((attendClasses*100) / totClasses);

Here Your attendClasses and totClasses are int value. So division of two int value attendClasses/totClasses will result into 0. As here totClasses>attendClasses.

edited May 04 '15 at 18:29

answered May 04 '15 at 18:20

Dhaval Patel

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I tried as u said but the percentage is getting calculated after I click in add percentage and precision values are getting ignored – user3530830 May 04 '15 at 18:27
You need to cast result in float like float percentage = (float)(attendClasses*100) / totClasses; for precision values. – Dhaval Patel May 04 '15 at 18:50

Ted · Answer 2 · 2015-05-04T18:34:06.840

-1

try using Float.toString(percentage); instead of String.valueOf(percentage);

edited May 04 '15 at 18:34

answered May 04 '15 at 18:27

Ted

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percentage is a primitive type. – Dhaval Patel May 04 '15 at 18:31
`float f = Float.parseFloat("25"); String s = Float.toString(25.0f);` check this for reference http://stackoverflow.com/questions/7552660/java-convert-float-to-string-and-string-to-float – Ted May 04 '15 at 18:31

Working with numbers in android

2 Answers2