Setting increase/decrease interval of NumberPicker

Question

Is it possible to set the increase/decrease interval of NumberPicker to other value? For instance to 50 (50, 100, 150, 200, 250 etc)? Or do it require some customization/hack?

Answer 1

I think you can do this:

• Initialise a displayed array values for your picker :

  int NUMBER_OF_VALUES = 10; //num of values in the picker
  int PICKER_RANGE = 50;
  ...
  String[] displayedValues  = new String[NUMBER_OF_VALUES];
  //Populate the array
  for(int i=0; i<NUMBER_OF_VALUES; i++)
      displayedValues[i] = String.valueOf(PICKER_RANGE * (i+1));
  /* OR: if the array is easy to be hard-coded, then just hard-code it:
     String[] displayedValues = {"50", "100", "150", .....}; */
  

• Set the displayed array to your picker :

  /* 
  NOTE: Your picker range has to be [0, displayedValues.size()-1] to be 
        consistent with the array index (displayedValues index).
  */
  //ToDo: Initialize the picker first.
  numPicker.setMinValue(0); 
  numPicker.setMaxValue(displayedValues.size()-1);
  numPicker.setDisplayedValues(displayedValues);
  

• When you want to get/set the value of the picker :

  //To get the current value in the picker
  choosenValue = displayedValues[numPicker.getValue()]; 
  //To set a new value (let's say 150)
  for( int i=0; i<displayedValues.length ; i++ )
      if( displayedValues[i].equals("150") )
           numPicker.setValue(i);
  

Finally, there is a great easy-to-customize widget called android-wheel. You can check it out and use it if you like.

Answer 2

@ iturki's last point setting a value. Because valueInNumberPicker X PICKER_RANGE = valueInDisplayedValueArray So we can avoid the for loop by:

// PICKER_RANGE= 50 so 150/50 -1 = 2, numPicker.setValue(2) == 150
numPicker.setValue(150/PICKER_RANGE -1); 

My 2 cents.

By the way, great answer by iturki.

Answer 3

I have used the onScrollListener for scrolling with different step sizes and the onValueChanged for handling direct input with the number keyboard. For the use you need the variable oldValue which is available in both listeners.

int oldValue = 0;

In the onScrollListener I used the STATE_IDLE just because it works and i don t understand 100 % the difference for this use between all three...think you can use them either for this purpose.

You need the global oldValue variable to know the old value before scrolling. I haven t found a other solution. The if clauses is the min (0) and max (1000) boarder.

speedPicker.setValue(oldValue);
vitess.setProgress(oldValue);
((MainActivity) getActivity()).setSpeed(oldValue);

These three calls update my elements (vitess is a coupled progressBar, speedPicker is the numberPicker).

In the onValueChange I update also the elements and i set the oldValue.

By the way stepSize here is 100.

    speedPicker.setOnScrollListener(new OnScrollListener() {
        public void onScrollStateChange(NumberPicker speedPicker, int scrollState) {

            if (scrollState == NumberPicker.OnScrollListener.SCROLL_STATE_IDLE) {
                if (speedPicker.getValue() < oldValue){
                    if (speedPicker.getValue() >= 100)
                        oldValue-=100;
                    else
                        oldValue = 0;

                }
                else{
                    if (speedPicker.getValue() <= 900)
                        oldValue+=100;
                    else
                        oldValue = 1000;
                }

                speedPicker.setValue(oldValue);
                vitess.setProgress(oldValue);
                ((MainActivity) getActivity()).setSpeed(oldValue);

            }
            else if (scrollState == NumberPicker.OnScrollListener.SCROLL_STATE_FLING) {
            }
            else if (scrollState == NumberPicker.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
            }
        }
    });

    speedPicker.setOnValueChangedListener(new OnValueChangeListener() {
        public void onValueChange(NumberPicker speedPicker, int oldVal, int newVal) {

            oldValue = oldVal;
            speedPicker.setValue(newVal);
            vitess.setProgress(newVal);
            ((MainActivity) getActivity()).setSpeed(newVal);

        }
    });

This code works after some testing quit good for me.

This answer was inspired by jpintado. See his answer in Android NumberPicker OnValueChangeListener

Answer 4

A bit late in the day, but this works for me...

    numberPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker numberPicker, int oldVal, int newVal) {
            if (newVal > oldVal) {
                numberPicker.setValue(newVal+(myInterval-1));
            } else if (newVal < oldVal)
                numberPicker.setValue(newVal-(myInterval-1));
        }
    });