Android - ViewPager Adapter, set primary item before adapter is instantiated

Question

I know i can do

 viewPager.setCurrentItem(position) 

to set my view pager at the desired position. My question is if and how i can do this before the adapter is instantiated.

Meaning that if I do

pagerAdapter = new ViewPagerAdapter(arg1,arg2....);
viewPager.setAdapter(pagerAdapter);
viewPager.setCurrentItem(position);

item 0 is first build and after that the item at the desired position is also build. Which takes double the time...In my adapter each item needs quite a lot of work to be build, so it would be best to avoid the 0 position item to be build if possible. Maybe by passing the desired position as an argument at the adapter's instantiation...?

Any way to do that?

Answer 1

You can fool the viewpager to start at a given position before the adapter is set, by calling onRestoreInstanceState, like this:

int currentItem = 5;

Parcel parcel = Parcel.obtain();
writeParcelable(BaseSavedState.EMPTY_STATE, 0);

writeInt(currentItem);
writeParcelable(null, 0);

setDataPosition(0);
SavedState savedState = ViewPager.SavedState.CREATOR.createFromParcel(parcel);

mPager.onRestoreInstanceState(savedState);

mPager.setAdapter(mAdapter);