Dynamically change ViewPagerIndicator titles

问题

My current project uses some ListFragments to show rows of data. The rows get updated dynamically every some seconds. The amount of rows varies with every update and in every ListFragment.

I would like to show the amount of rows to the user, and think that the perfect place for that would be next to the Fragment's title in the ViewPagerIndicator. I provided a sample image for better comprehension:

Sadly I am pretty clueless how to achieve this. I tried the following:

public class PagerAdapter extends FragmentPagerAdapter {
    private int numOne = 0;
    private int numTwo = 0;

    // ...

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
        case 0:
            return "List 1 (" + numOne + ")";
        case 1:
            return "List 2 (" + numTwo + ")";
        default:
            return "";
    }

    public void setNumOne(int num) {
        this.numOne = num;
    }

    public void setNumTwo(int num) {
        this.numTwo = num;
    }
}

When I now call the setNumXXX() method, nothing happens, until I move between fragments, what seems to trigger the getPageTitle() to fire.

My question is: How can I force an update of the title(s), everytime when the num value changes?

回答1:

If you call notifyDataSetChanged() on the indicator instance it will redraw itself and grab the new titles.

来源：https://stackoverflow.com/questions/12186754/dynamically-change-viewpagerindicator-titles