java - How to show element by timer?

Question

I have a problem. I have an Activity with ViewPager which have some Fragments.

In my first Fragment I have some elements. Lets say an ImageView, TextView. How to make them visible by timer when you completely open the page of ViewPager?!

I used this code below in my MainActivity.java document to make that ImageView visible by timer but it works not as I expected. When i want to go to next page by scrolling and touch the screen ImageView dissapear. Why its happened?!

final ImageView mImageView = (ImageView) findViewById(R.id.earth);
mImageView.setVisibility(View.INVISIBLE);
mImageView.postDelayed(new Runnable() {
public void run() {
       mImageView.setVisibility(View.VISIBLE);
}}, 5000);

Any help is appreciated. Thanks!

My new edits:

// Initialize the ViewPager and set an adapter
        ViewPager pager = (ViewPager) findViewById(R.id.pager);
        pager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));

        // Bind the tabs to the ViewPager
        PagerSlidingTabStrip tabs = (PagerSlidingTabStrip) findViewById(R.id.tabs);
        tabs.setViewPager(pager);
//open concrete page of ViewPager. setCurrentItem(index of page)
pager.setCurrentItem(1);

tabs.setOnPageChangeListener(new OnPageChangeListener() {
            //This method will be invoked when the current page is scrolled, either as part of a program initiated smooth scroll or a user initiated touch scroll.
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            //This method will be invoked when a new page becomes selected.
            @Override
            public void onPageSelected(int position) {
                final ImageView mImageView = (ImageView) findViewById(R.id.earth);
                mImageView.setVisibility(View.INVISIBLE);
                if (position == 0) {
                    mImageView.postDelayed(new Runnable() {
                        public void run() {
                            mImageView.setVisibility(View.VISIBLE);
                        }
                    }, 5000);
                }
            }

            //Called when the scroll state changes.
            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

My Problem is conflict with TABS and ViewPager. When I use tabs.setOnPageChangeListener(new OnPageChangeListener() i have conflict with pager.setCurrentItem(1); which shows concrete page when Activity first opened. In my case its shows 2-d page when Activity first opened but Tab shows that opened 1-st page. WHY?! How to solve this problem?!

Answer 1

I would not use a timer. It would either fire too early, or too late during which your UI looks bad. Use the pager's events to know when to update your UI. For example, you can probably use OnPageChangedListener:

    pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
       @Override
       public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

       }

       @Override
       public void onPageSelected(int position) {
            // Now displaying page at position
       }

       @Override
       public void onPageScrollStateChanged(int state) {

       }
   };