import android.content.Context;
import android.graphics.drawable.ColorDrawable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.NumberPicker;
import java.lang.reflect.Field;

public class TextConfigNumberPicker extends NumberPicker {

    public TextConfigNumberPicker(Context context) {
        super(context);
    }

    public TextConfigNumberPicker(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public TextConfigNumberPicker(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }


    @Override
    public void addView(View child) {
        this.addView(child, null);


    }

    @Override
    public void addView(View child, ViewGroup.LayoutParams params) {
        this.addView(child, 0, params);
    }

    @Override
    public void addView(View child, int index, ViewGroup.LayoutParams params) {
        super.addView(child, index, params);
        updateView(child);
    }

    private void updateView(View view) {
        if (view instanceof EditText) {
            //Set the color and size of the general (default) text
            ((EditText) view).setTextColor(getResources().getColor(R.color.whiter));
            ((EditText) view).setTextSize(13);
        }
        try {
                         //Set the size and color of the dividing line
            Field mSelectionDivider = this.getFile("mSelectionDivider");
            mSelectionDivider.set(this, new ColorDrawable(getResources().getColor(R.color.pickline)));
            mSelectionDivider.set(this, 10);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


         //Reflective acquisition control mSelectionDivider mInputText currently selected view
    public Field getFile(String fieldName) {
        try {
                         //Set the color value of the dividing line
            Field pickerFields = NumberPicker.class.getDeclaredField(fieldName);
            pickerFields.setAccessible(true);
            return pickerFields;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

         //Set the style of the selected control. Note that it should be adjusted in setOnValueChangedListener or setOnScrollChangeListener, setOnScrollListener
         // Use picker.performClick(); the animation effect is different in the two cases
         //At the same time pay attention to his substitute position after the current control is initialized, otherwise it will not be obtained
    public void setMInputStyle(Float size) {
        Field mInputText = this.getFile("mInputText");
        try {
            ((EditText) mInputText.get(this)).setTextSize(size);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }
}

Note that the style of the selected control should be set after the current control is initialized. Usage:

 TextConfigNumberPicker numberPicker = dialog.findViewById(R.id.np);
 numberPicker.setMInputStyle(16f);
   //setOnValueChangedListener or setOnScrollChangeListener, setOnScrollListener
        numberPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
            @Override
            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
                             picker.performClick();//Refresh the selected state
            }
        });