How to use

setOffscreenPageLimit

method

in

androidx.viewpager.widget.ViewPager

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
      WindowManager.LayoutParams.FLAG_FULLSCREEN);
  setContentView(R.layout.activity_awesomedesign);
  setTitle("SimpleChartDemo");
  ViewPager pager = findViewById(R.id.pager);
  pager.setOffscreenPageLimit(3);
  PageAdapter a = new PageAdapter(getSupportFragmentManager());
  pager.setAdapter(a);
  AlertDialog.Builder b = new AlertDialog.Builder(this);
  b.setTitle("This is a ViewPager.");
  b.setMessage("Swipe left and right for more awesome design examples!");
  b.setPositiveButton("OK", new OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {
      dialog.dismiss();
    }
  });
  b.show();
}

setContentView(R.layout.activity_detail);
ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
viewPager.setOffscreenPageLimit(0);
viewPager.setAdapter(new PagerAdapter() {
  @Override

mViewPager.setOffscreenPageLimit(8);
slidingTabLayout = (SlidingTabLayout) findViewById(R.id.sliding_tabs);
slidingTabLayout.setViewPager(mViewPager);

viewPager.setOffscreenPageLimit(3);

viewpagerItem.setOffscreenPageLimit(1);//预加载数据页
viewpagerItem.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
  @Override

public void bind(final ViewPager viewPager, PagerSlidingTabStrip tabLayout, final FloatingActionButton genericFab) {
  viewPager.setPageMargin(viewPager.getResources().getDimensionPixelOffset(R.dimen.divider));
  viewPager.setPageMarginDrawable(R.color.blackT12);
  viewPager.setOffscreenPageLimit(2);
  viewPager.setAdapter(this);
  tabLayout.setViewPager(viewPager);
  tabLayout.setOnTabReselectedListener(new PagerSlidingTabStrip.OnTabReselectedListener() {
    @Override
    public void onTabReselected(int position) {
      Fragment fragment = getItem(viewPager.getCurrentItem());
      if (fragment != null) {
        ((Scrollable) fragment).scrollToTop();
      }
    }
  });
  viewPager.setCurrentItem(mDefaultItem);
  toggleFabs(false, genericFab);
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_downloads);
  initToolBar();
  SupportedDownloads.KernelContent content = new SupportedDownloads.KernelContent(getIntent().getStringExtra(JSON_INTENT));
  getSupportActionBar().setTitle(Utils.htmlFrom(content.getName()).toString());
  final ViewPager viewPager = findViewById(R.id.viewpager);
  LinkedHashMap<String, Fragment> items = new LinkedHashMap<>();
  List<SupportedDownloads.KernelContent.Feature> features = content.getFeatures();
  List<SupportedDownloads.KernelContent.Download> downloads = content.getDownloads();
  if (content.getShortDescription() != null && content.getLongDescription() != null) {
    items.put(getString(R.string.about), AboutFragment.newInstance(content));
  }
  if (features.size() > 0) {
    items.put(getString(R.string.features), FeaturesFragment.newInstance(features));
  }
  if (downloads.size() > 0) {
    items.put(getString(R.string.downloads), DownloadKernelFragment.newInstance(downloads));
  }
  viewPager.setOffscreenPageLimit(items.size());
  PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager(), items);
  viewPager.setAdapter(pagerAdapter);
  TabLayout tabLayout = findViewById(R.id.tablayout);
  tabLayout.setupWithViewPager(viewPager);
  viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}

adapter = new AddTorrentPagerAdapter(activity.getSupportFragmentManager(), activity);
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(AddTorrentPagerAdapter.NUM_FRAGMENTS);
viewPager.post(() -> {
  updateInfoFragment();

mMyMusicViewPager.setAdapter(mMyMusicPagerAdapter);
mMyMusicViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
mMyMusicViewPager.setOffscreenPageLimit(2);
tabLayout.addOnTabSelectedListener(this);

viewPager.setOffscreenPageLimit(mItems.size());
PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager(), mItems);
viewPager.setAdapter(pagerAdapter);

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  getInjector().cafeteriaComponent()
      .cafeteriaModule(new CafeteriaModule())
      .build()
      .inject(this);
  viewPager = findViewById(R.id.pager);
  viewPager.setOffscreenPageLimit(50);
  adapter = createArrayAdapter();
  spinner = findViewById(R.id.spinnerToolbar);
  spinner.setAdapter(adapter);
  spinner.setOnItemSelectedListener(this);
  sectionsPagerAdapter = new CafeteriaDetailsSectionsPagerAdapter(getSupportFragmentManager());
  ViewModelFactory<CafeteriaViewModel> factory = new ViewModelFactory<>(viewModelProvider);
  cafeteriaViewModel = ViewModelProviders.of(this, factory).get(CafeteriaViewModel.class);
  cafeteriaViewModel.getCafeterias().observe(this, this::updateCafeteria);
  cafeteriaViewModel.getSelectedCafeteria().observe(this, this::onNewCafeteriaSelected);
  cafeteriaViewModel.getMenuDates().observe(this, this::updateSectionsPagerAdapter);
  cafeteriaViewModel.getError().observe(this, isError -> {
    if (isError) {
      showError(R.string.error_something_wrong);
    } else {
      showContentLayout();
    }
  });
}