Getting float/double from NumberPicker

Question

I am trying the https://github.com/SimonVT/android-numberpicker library and the reference is https://developer.android.com/reference/android/widget/NumberPicker.html#getValue%28%29 Now both, the API level 11 NumberPicker returns int value in getValue method and also the SimonVT numberpicker returns int value.

But I had set double values in the number picker by using following code:

String[] nums = {"1","1.5","2","2.5","3","3.5","4","4.5","5","5.5","6","6.5","7","7.5","8","8.5","9"};

final NumberPicker listeningScorenp = (NumberPicker) findViewById(R.id.listeningScore);
listeningScorenp.setMaxValue(nums.length-1);
listeningScorenp.setMinValue(0);
listeningScorenp.setWrapSelectorWheel(false);
listeningScorenp.setDisplayedValues(nums);

Now I am stuck with how to retrieve the float/double values from NUmberPicker.

Answer 1

I just tested using your code. getValue() actually returns the index of the item selected (only when you set the displayed values). All you'll need to do is parse the string and you will have what you wanted.

String[] nums = {"1","1.5","2","2.5","3","3.5","4","4.5","5","5.5","6","6.5","7","7.5","8","8.5","9"};
int index = listeningScorenp.getValue();
String val = nums[index];
float selectedFloat = Float.parseFloat(val);

Answer 2

In Kotlin, you can use this handy NumberPicker extension which presents a dialog – under the wraps it scales your Double values into a fitting Int range and converts the Int values back to Doubles before calling any of the callback. So it basicallly hides away the fact that NumberPicker only supports Int. It just feels like NumberPicker would actually support Double, try it out!

Here's the Fragment extension you can to copy & paste:

fun Fragment.showNumberPickerDialog(
    title: String,
    value: Double,
    range: ClosedRange<Double>,
    stepSize: Double,
    formatToString: (Double) -> String,
    valueChooseAction: (Double) -> Unit
) {
    val numberPicker = NumberPicker(context).apply {
        setFormatter { formatToString(it.toDouble() * stepSize) }
        wrapSelectorWheel = false

        minValue = (range.start / stepSize).toInt()
        maxValue = (range.endInclusive / stepSize).toInt()
        this.value = (value.toDouble() / stepSize).toInt()

        // NOTE: workaround for a bug that rendered the selected value wrong until user scrolled, see also: https://stackoverflow.com/q/27343772/3451975
        (NumberPicker::class.java.getDeclaredField("mInputText").apply { isAccessible = true }.get(this) as EditText).filters = emptyArray()
    }

    MaterialAlertDialogBuilder(context)
        .setTitle(title)
        .setView(numberPicker)
        .setPositiveButton("OK") { _, _ -> valueChooseAction(numberPicker.value.toDouble() * stepSize) }
        .setNeutralButton("Cancel") { _, _ -> /* do nothing, closes dialog automatically */ }
        .show()
}

Then you can use it like this:

showNumberPickerDialog(
    title = "Your Weight",
    value = 75.0, // in kilograms
    range = 10.0 .. 300.0,
    formatToString = { "$it kg" },
    valueChooseAction = { saveNewWeight(it) }
)