Android : How to prevent users from entering numbers with more than 3 decimal places

Question

I've got an EditText in my app, in which I don't want users to enter numbers with more than 3 decimal places. This is because in the SQL server database that is going to store that data I send from the phone has this data type :

numeric(15, 3)

Do you have any idea how I can do that?

I've already set these values, but they would only help me partially:

android:maxLength="15"
android:lines="1"
android:inputType="numberDecimal"

Edit

This is what I tried:

            mQuantityEditText.addTextChangedListener(new TextWatcher(){
        @Override
        public void afterTextChanged(Editable s) {
            String str = mQuantityEditText.getText().toString();
            DecimalFormat format=(DecimalFormat) DecimalFormat.getInstance();
            DecimalFormatSymbols symbols=format.getDecimalFormatSymbols();
            char sep=symbols.getDecimalSeparator();


            int indexOFdec =  str.indexOf(sep);         

            if(indexOFdec >=0) {
               if(str.substring(indexOFdec,str.length()-1).length() >3)
               {
                    s.replace(0, s.length(),str.substring(0, str.length()-1));                    
               }
            }
         }
        @Override
         public void beforeTextChanged(CharSequence s, int start, int count, int after) {

         }
        @Override
         public void onTextChanged(CharSequence s, int start, int before, int count) {                      


         }      
     });

It worked because it only allows 3 decimal places, but I'm still not sure how to control the max number of digits to fit in the numeric(15,3)

Thanks in advance.

Why not just sending the number rounded to 3 decimal places. — biegleux, Oct 17 '14 at 11:59
Have a look here http://stackoverflow.com/questions/5357455/limit-decimal-places-in-android-edittext — Roberto B., Oct 17 '14 at 12:00
Why not implement onTextChange listener and perform a regex? — Pedro Oliveira, Oct 17 '14 at 12:00
@biegleux If let users enter numbers with too many decimal places, when I show the data or when I edit the data locally on the phone I end up with the numbers displayed in what it looks like scientific notation — Axel, Oct 17 '14 at 12:06
I know, it's just that didn't want to go through all the pain of having to format the data every time I need to display it and then round it when I need to send it to the server. — Axel, Oct 17 '14 at 12:12
Still you have to validate on server against malicious input. — biegleux, Oct 17 '14 at 12:24
I would use a textwatcher and dynamically change the max length as soon as the user inputs a decimal separator. — njzk2, Oct 17 '14 at 14:10

score 0 · Answer 1 · answered Oct 17 '14 at 12:06

For the limited number of character, you can add a Android API filter :

InputFilter[] FilterArray = new InputFilter[1];
FilterArray[0] = new InputFilter.LengthFilter(8);
editEntryView.setFilters(FilterArray);

For the numeric editText, there is also a obscur solution :

DigitsKeyListener MyDigitKeyListener = new DigitsKeyListener(true, true); 
editEntryView.setKeyListener( MyDigitKeyListener );

How is that obscure? (Also it does not limit the size of the input) — njzk2, Oct 17 '14 at 14:09

Rohitashv jain · Answer 2 · 2014-10-18T06:29:54.407

public class RestrictDecimal implements InputFilter {

Pattern mPattern;

public RestrictDecimal(int beforePoint,int afterPoint) {
    mPattern=Pattern.compile("[0-9]{0," + (beforePoint-1) + "}+((\\.[0-9]{0," + (afterPoint-1) + "})?)||(\\.)?");
}

@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {

        Matcher matcher=mPattern.mat`enter code here`cher(dest);       
        if(!matcher.matches())
            return "";
        return null;
    }

}

// Set for edit Text
editEntryView.setFilters(new InputFilter[] {new RestrictDecimal(15,3)});

please format your code and explain why your solution is an answer to the question — njzk2, Oct 17 '14 at 14:09

Android : How to prevent users from entering numbers with more than 3 decimal places

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2 Answers2