How to set input type and format in EditText using kotlin?

Question

I want to force users to enter a Number and i'm using that (and it's working fine):

android:inputType="number"

I want to force the user to make the input just two numbers (Int or Double does not matter) and those numbers must be between 0 and 20 (or 0.0 and 20.0) : e.g : 0 or 0.0 1 or 1.5 (1.0 etc) . . . 20 or 20.0

Answer 1

Here's how I like to do this:

add this for edit text

 android:inputType="numberDecimal"  

(or)

android:digits="0123456789."

Kotlin::

class InputFilterMinMax(min:Float, max:Float): InputFilter {
    private var min:Float = 0.0F
    private var max:Float = 0.0F

    init{
        this.min = min
        this.max = max
    }

    override fun filter(source:CharSequence, start:Int, end:Int, dest: Spanned, dstart:Int, dend:Int): CharSequence? {
        try
        {
            val input = (dest.subSequence(0, dstart).toString() + source + dest.subSequence(dend, dest.length)).toFloat()
            if (isInRange(min, max, input))
                return null
        }
        catch (nfe:NumberFormatException) {}
        return ""
    }

    private fun isInRange(a:Float, b:Float, c:Float):Boolean {
        return if (b > a) c in a..b else c in b..a
    }
}

Then set the filter on your EditText:

myEditText.setFilters(arrayOf<InputFilter>(InputFilterMinMax(0.0F, 20.0F)))

Java:

public class InputFilterMinMax implements InputFilter {
    private float min;
    private float max;

    public InputFilterMinMax(float min, float max) {
        this.min = min;
        this.max = max;
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        //noinspection EmptyCatchBlock
        try {
            float input = Float.parseFloat(dest.subSequence(0, dstart).toString() + source + dest.subSequence(dend, dest.length()));
            if (isInRange(min, max, input))
                return null;
        } catch (NumberFormatException nfe) { }
        return "";
    }

    private boolean isInRange(float a, float b, float c) {
        return b > a ? c >= a && c <= b : c >= b && c <= a;
    }
}

Then set the filter on your EditText:

myEditText.setFilters(new InputFilter[]{new InputFilterMinMax(0.0, 20.0)});