How to start an activity from another Activity that uses tab layout?

Question

I have created tablayout in my app as follow:

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_place_info);
        getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
        getSupportActionBar().setCustomView(R.layout.action_bar);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("الموقع"));
        tabLayout.addTab(tabLayout.newTab().setText("تفاصيل التصنيف"));
        tabLayout.addTab(tabLayout.newTab().setText("ساعات العمل"));
        tabLayout.addTab(tabLayout.newTab().setText("المتطلبات"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        final PagerAdapter adapter = new PagerAdapter
                (getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        viewPager.setCurrentItem(4);
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());

                int position = tab.getPosition();
                switch(position){
                    case 0:
                        break;
                    case 1:
                        break;
                    case 2:
                        break;
                    case 3:
                        break;
                }

            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }

The Page adapter is:

public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;

public PagerAdapter(FragmentManager fm, int NumOfTabs) {
    super(fm);
    this.mNumOfTabs = NumOfTabs;
}

@Override
public Fragment getItem(int position) {

    switch (position) {
        case 0:
            LocationInfoFragment tab1 = new LocationInfoFragment();
            return tab1;
        case 1:
            RankInfoFragment tab2 = new RankInfoFragment();
            return tab2;
        case 2:
            WorkingHoursInfoFragment tab3 = new WorkingHoursInfoFragment();
            return tab3;
        case 3:
            WorkingHoursInfoFragment tab4 = new WorkingHoursInfoFragment();
            return tab4;
        default:
            return null;
    }
}

@Override
public int getCount() {
    return mNumOfTabs;
}
}

I know that when I want to start an activity I have to use Intent as follow:

Intent processesListAcitivity = new Intent(getApplicationContext(), ProcessesListAcitivity.class);
            startActivity(processesListAcitivity);

My question is where to put it:

in the switch in the first class, or in the page adapter ?!

Most likely, the answer is "neither". You start an activity when the user clicks on something that indicates it is time to start the activity, like a `Button` or action bar item or nav drawer entry. You do not start an activity because the user switched to some other tab, because then *the user cannot work with the contents of that tab*. — CommonsWare, Jan 28 '17 at 19:23
@CommonsWare : fair enough, but how to load my layout for that tab ? for example, if I needed to show a ListView ?! I want to be able to do that with tab change — McLan, Jan 28 '17 at 19:26
When do you want to open your activity? When the user switches the tab? If so, you're doing it wrong. — Anis LOUNIS aka AnixPasBesoin, Jan 28 '17 at 19:27
@AnixPasBesoin : Yes, when user switch between tabs .. in case I am doing it wrong, how to do it right then. thanks — McLan, Jan 28 '17 at 19:28
You can implement a [ViewPager.OnPageChangeListener](https://developer.android.com/reference/android/support/v4/view/ViewPager.OnPageChangeListener.html) and start youractivity in the onPageSelected callback. — Anis LOUNIS aka AnixPasBesoin, Jan 28 '17 at 19:32
[http://stackoverflow.com/questions/30539772/android-tablayout-android-design](http://stackoverflow.com/questions/30539772/android-tablayout-android-design) — Moien.Dev, Jan 28 '17 at 19:33
"but how to load my layout for that tab ? " -- that is the job of the fragment that you are showing in that tab. — CommonsWare, Jan 28 '17 at 19:38
@AnixPasBesoin : I don't have `onPageChnageListener` method to call. Beside, in the above code I am using `onAddOnPageChangeListener` which then has `onTabSelected` where I am implementing the `switch`. So, you are suggesting that I should start my activity in this `switch`, right ?! but again, what is the need for the PageAdaptor's switch that start the fragment ? — McLan, Jan 28 '17 at 19:52
It's not a method it's an interface. yourPager.setOnPageChangeListener( new ... ) see the link I sent you. — Anis LOUNIS aka AnixPasBesoin, Jan 28 '17 at 19:54
@AnixPasBesoin: please could you clarify for me my confusion. If I using `onPageSelected` with the `addOnPageChangeListener`, then why do I need the `PageAdapter` that inflate fragments ?! — McLan, Jan 28 '17 at 20:08
@CommonsWare: please could you clarify for me my confusion. If I using the fragment to load my layout, then why do I need the listeners in my activity ? — McLan, Jan 28 '17 at 20:19
You have two listeners there. `addOnPageChangeListener()` is to tie the `ViewPager` to the `TabLayout`. `addOnTabSelectedListener()` is not necessary, as you are not doing anything with it. In [this sample app](https://github.com/commonsguy/cw-omnibus/tree/master/DesignSupport/TabLayout), I use `TabLayout` with a `ViewPager` with neither of those listeners. — CommonsWare, Jan 28 '17 at 20:34

score 0 · Answer 1 · answered Feb 01 '17 at 18:33

private Stack<String> stack;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (stack == null)
    stack = new Stack<String>();
// start default activity
push("FirstStackActivity", new Intent(this, Tab_SampleActivity.class));
}

@Override
public void finishFromChild(Activity child) {
pop();
}

@Override
public void onBackPressed() {
pop();

}

public void push(String id, Intent intent) {
Window window = getLocalActivityManager().startActivity(id,               intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
 if (window != null) {
    stack.push(id);
    setContentView(window.getDecorView());
}
}

public void pop() {
if (stack.size() == 1)
    finish();
LocalActivityManager manager = getLocalActivityManager();
manager.destroyActivity(stack.pop(), true);
if (stack.size() > 0) {
    Intent lastIntent = manager.getActivity(stack.peek()).getIntent();
    Window newWindow = manager.startActivity(stack.peek(), lastIntent);
    setContentView(newWindow.getDecorView());
}

}

How to start an activity from another Activity that uses tab layout?

1 Answers1