public void setAdapter(PagerAdapter adapter) {
        if (mAdapter != null) {
            mAdapter.unregisterDataSetObserver(mObserver);
            mAdapter.startUpdate(this);
            for (int i = 0; i < mItems.size(); i++) {
                final ItemInfo ii = mItems.get(i);
                mAdapter.destroyItem(this, ii.position, ii.object);
            }
            mAdapter.finishUpdate(this);
            mItems.clear();
            removeNonDecorViews();
            mCurItem = 0;
            scrollTo(0, 0);
        }

        final PagerAdapter oldAdapter = mAdapter;
        mAdapter = adapter;
        mExpectedAdapterCount = 0;

        if (mAdapter != null) {
            if (mObserver == null) {
                mObserver = new PagerObserver();
            }
            mAdapter.registerDataSetObserver(mObserver);
            mPopulatePending = false;
            final boolean wasFirstLayout = mFirstLayout;
            mFirstLayout = true;
            mExpectedAdapterCount = mAdapter.getCount();
            if (mRestoredCurItem >= 0) {
                mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader);
                setCurrentItemInternal(mRestoredCurItem, false, true);
                mRestoredCurItem = -1;
                mRestoredAdapterState = null;
                mRestoredClassLoader = null;
            } else if (!wasFirstLayout) {
                populate();
            } else {
                requestLayout();
            }
        }

        if (mAdapterChangeListener != null && oldAdapter != adapter) {
            mAdapterChangeListener.onAdapterChanged(oldAdapter, adapter);
        }
    }
Set a PagerAdapter that will supply views for this pager as needed.

@param adapter Adapter to use
dkplayer-sample/src/main/java/xyz/doikki/dkplayer/widget/VerticalViewPager.java