Android NumberPicker with Formatter doesn't format on first rendering

I also encountered this annoying little bug. Used a technique from this answer to come up with a nasty but effective fix.

NumberPicker picker = (NumberPicker)view.findViewById(id.picker);
picker.setMinValue(1);
picker.setMaxValue(5);
picker.setWrapSelectorWheel(false);
picker.setFormatter(new NumberPicker.Formatter() {
    @Override
    public String format(int value) {
        return my_formatter(value);
    }
});

try {
    Method method = picker.getClass().getDeclaredMethod("changeValueByOne", boolean.class);
    method.setAccessible(true);
    method.invoke(picker, true);
} catch (NoSuchMethodException e) {
    e.printStackTrace();
} catch (IllegalArgumentException e) {
    e.printStackTrace();
} catch (IllegalAccessException e) {
    e.printStackTrace();
} catch (InvocationTargetException e) {
    e.printStackTrace();
}

Calling that private changeValueByOne method immediately after instantiating my number picker seems to kick the formatter enough to behave how it should. The number picker comes up nice and clean with the first value formatted correctly. Like I said, nasty but effective.

dgel's solution doesn't work for me: when I tap on the picker, formatting disappears again. This bug is caused by input filter set on EditText inside NumberPicker when setDisplayValues isn't used. So I came up with this workaround:

Field f = NumberPicker.class.getDeclaredField("mInputText");
f.setAccessible(true);
EditText inputText = (EditText)f.get(mPicker);
inputText.setFilters(new InputFilter[0]);

I had the same problem and I used the setDisplayedValues() method instead.

int max = 99;
String[] values = new String[99];
values[0] = “-” + mSingle
values[1] = 
for(int i=2; i<=max; i++){
    makeNames[i] = String.valueOf(i) + mMultiple;
}
picker.setMinValue(0);
picker.setMaxValue(max);
picker.setDisplayedValues(values)

This doesn't allow the user to set the value manually in the picker though.