Tab+swipe Gesture, Custom grid view, Fragments

Question

Well I have this app with swipe gesture functionality between fragments which they contains images which are located in the resources folders .. but when i swipe left and right I noticed that the performance is bad and slow .. Any suggestions to improve it?

And here is the header of the main activity code :

public class MainActivity extends FragmentActivity implements
        ActionBar.TabListener {

    private ViewPager viewPager;
    private TabsPagerAdapter mAdapter;
    private ActionBar actionBar;
    // Tab titles
    private String[] tabs = {"Roman Curtain", "Roller Blinds", "Wooden Blinds" ,"Kitchen Blinds"};
//  
    @SuppressLint("NewApi")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Initilization
        viewPager = (ViewPager) findViewById(R.id.pager);
        actionBar = getActionBar();
        mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

        viewPager.setAdapter(mAdapter);
        actionBar.setHomeButtonEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        

        // Adding Tabs
        for (String tab_name : tabs) {
            actionBar.addTab(actionBar.newTab().setText(tab_name)
                    .setTabListener(this));
        }

        /**
         * on swiping the viewpager make respective tab selected
         * */
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                // on changing the page
                // make respected tab selected
                actionBar.setSelectedNavigationItem(position);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
            }
        });
    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // on tab selected
        // show respected fragment view
        viewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    }

and here is tab pager adapter :

public class TabsPagerAdapter extends FragmentPagerAdapter {

    public TabsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int index) {

        switch (index) {
        case 0:
            return new RomanCurtains();
        case 1:
            return new RollerBlinds();
        case 2:
            return new WoodenBlinds();
        case 3:
            return new KitchenBlinds();
//      case 4:
//          return new KitchenBlinds();
        }

        return null;
    }

    @Override
    public int getCount() {
        // get item count - equal to number of tabs
        return 4;
    }

}

Answer 1

There may be a two reason for the bad performance

1. Your images are too big and takes too much space in the memory You can put the images in assets folder and then use Picasso library to use them. It will improve the performance. https://github.com/square/picasso
2. All the pages in the ViewPager is in the memory if you use PagerAdapter or FragmentPagerAdapter. If you use FragmentStatePagerAdapter only the visible page and the pages adjacent to that page are kept in the memory. This will improve the performance too.

Answer 2

Use ViewPager.setOffscreenPageLimit(int limit)