TabLayout：切换片段时滞后

Question

I have 50 fragments with at least 20 components in each one. I'm experiencing a delay (lag) when switching tabs, even though I've used this statement:

viewpager.setOfscreenPageLimit(2)

but it didn't work. I tried to initialize the tablayout with the fragments in a different thread (apart from the UI thread), like this:

new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {

                        PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager());

                        // Add Fragments  
                        // Here there are 50 fragments, but I added just 2 
                        //fragments for simplicity

                        //region Phase Five
                        adapter.addFragment(new PhaseFiveTestTwoFragment(), "");

                        adapter.addFragment(new LessonOneFragment(), "");
                        //endregion

                        viewPager.setOffscreenPageLimit(2);

                        viewPager.setAdapter(adapter);

                        tabLayout.setupWithViewPager(viewPager);

                    }
                }, 100);

But, I still had a lag when switching tabs.

This is an example of how many components I have:

Any help will be appreciated.

Answer 1

Don't use Handler for this one. You really don't need to set up a delay for this

Use this as your ViewPagerAdapter (Which is just a standard ViewPager Adapter Structure):

 private class ViewPagerAdapter extends FragmentPagerAdapter { private final List < Fragment > mFragList = new ArrayList < > (); public ViewPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { return mFragList.get(position); } @Override public int getCount() { return mFragList.size(); } public void addFragmentI(Fragment fragment) { mFragList.add(fragment); } private void removeFragmentI(Collection < Fragment > fragment) { mFragList.removeAll(fragment); } } 

And for setting Adapter Use something like This:

 Fragment[] frags = { new Fragment1(), new Fragment2(), new Fragment3(), new Fragment4(), new Fragment5() }; for (int i = 0; i < tabCount; i++) { pagerAdapter.addFragmentI(frags[i]); } mViewPager.setAdapter(pagerAdapter); mTabLayout.setupWithViewPager(mViewPager); mTabLayout.setTabGravity(TabLayout.GRAVITY_CENTER); mTabLayout.setTabMode(TabLayout.MODE_SCROLLABLE); 

This must work without a glitch. Keep your Fragments Light as well