如何从ViewPager收集数据？

Question

I made an activity which is simply a viewpager with a few tabs. Each tab is like a form that the user needs to fill out. When the user is done, the data from the view pager should be collected and sent back as a result. I almost have this working but for some reason the data on my first tab seems to get reset when the user gets to the third tab. I'm guessing this is due to some view recycling in the pager. Anyways, I'm wondering if there is some easy way to gather all the data from the different tabs or do I have to create some kind of tight coupling between the activity and viewpager object?

Answer 1

you have to use SmartFragmentStatePagerAdapter as described here " https://guides.codepath.com/android/ViewPager-with-FragmentPagerAdapter " and than need to

vpPager.setOffscreenPageLimit(3);

Your issue should be resolved. :)

Answer 2

A viewpager will kill off the fragment if it is 2 pages away from the current page. It then recreates it when the pager is on a page that is 1 step away from it.

You should move your form data into your activity/fragment that is holding the viewpager and use fragment listeners to update your data accordingly

For example, you could use a fragment listener like below to pass the data to/from the containing activity

public interface MyFragmentListener{
    void saveMyFormData(MyFormData formData);
    MyFormData getFormData();
}
private MyFragmentListener mListener;

//initialise fragment listener in onAttach (or elsewhere)

private void initFormView(){
    MyFormData data = mListener.getFormData();
    //do stuff with data
}

private void saveData(){
    mListener.saveMyFormData(myFormDataObject);
}