Develop Reference

Using unknown number of tabs

I want to create an activity that can display any number of tabs, without creating an activity for each tab.
Is it possible?
The only way I saw creating tabs included creating an activity for each one.

You can try as follows ,
Extend your activity from ActionBarActivity and add required number of tabs programmatically ,
ActionBar.TabListener tabListener;
mactionBar = getActionBar();
mactionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
tabListener=new ActionBar.TabListener() {
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
displayTabs(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
displayTabs(tab.getPosition());
}
};
mactionBar.addTab(mactionBar.newTab().setText(<any text>).setTabListener(tabListener));
//call the same method for required number of tabs
Call the same fragment for each tab click
private void displayTabs(int position)
{
Fragment fragment = null;
switch (position) {
case 0:
fragment = new YourFragment();
break;
case 1:
fragment = new YourFragment();
break;
// same for required numder of cases
default:
break;
}
if (fragment != null)
{
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(<container id>, fragment).commit();
}
}

onCreateView not called for tabs in actionbar TabsAdapter for second time tab selected?

I have a tabbed application built with fragments and ActionBarSherlock. I have 3 tabs, with 3 ListFragment's Here's what's happening.
When I select any tab, the onCreate method for the associated fragment is called as expected at first time but not at second. The problem is that the onCreate method is called for the next adjacent tab but not selected tab.
Click on tab2 and onCreate of tab3 is called but not tab2.
Actually my requirement is, when i change some data in tab1 means fragment1. those changes are not effected in fragment2, when i select tab2 (fragment2) it means fragment2 onCreate() was not calling. why it's not refreshing the fragment properly. this is the adapter i am using.
private class TabsAdapter extends FragmentPagerAdapter implements ViewPager.OnPageChangeListener, ActionBar.TabListener {
public TabsAdapter(FragmentActivity activity, ActionBar actionBar, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mActionBar = actionBar;
mViewPager = pager;
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(ActionBar.Tab tab, Class<?> clss, int tabId) {
mTabs.add(clss.getName());
mTabsId.add(tabId);
mActionBar.addTab(tab.setTabListener(this));
notifyDataSetChanged();
}
public Integer getIdForPosition(int position) {
if (position >= 0 && position < mTabsId.size()) {
return mTabsId.get(position);
}
return null;
}
#Override
public int getCount() {
return mTabs.size();
}
#Override
public Fragment getItem(int position) {
//TabInfo info = mTabs.get(position);
return Fragment.instantiate(mContext, mTabs.get(position), new Bundle());
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Log.i(TAG, "*******tab selected*******" +tab);
clearDetails();
if (mViewPager.getCurrentItem() != tab.getPosition()) {
mViewPager.setCurrentItem(tab.getPosition(), true);
}
}
#Override
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
if (mCurrentPosition == position) {
}
mNextPosition = position;
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}

From this page:
The fragment of each page the user visits will be kept in memory,
though its view hierarchy may be destroyed when not visible.
This means that your fragments that are not visible to the user are still being kept in memory, so their onCreate methods won't be called when they're redisplayed. You can force them to be kicked out of memory when you switch pages by setting the ViewPager's offscreen page limit to 0.
A better way might be to use some sort of external data model shared between your Fragments and then use your onPageSelected method to tell the Fragment to update itself based on the data model when brought into view.

when you are on a Tab:(n), only Tab:(n-1) and Tab:(n+1) will be alive in the memory, for memory usage optimization. Rest all Tabs will be destroyed, thats the reason why when you come back to the first Tab, its onCreateView is being called again.
Actually Tab:1's onCreateView will be called even if you click Tab:2 because its the neighbourhood Tab.
One solution i got is:
change the OffscreenPageLimit of the ViewPager. Its default value is 1
Try changing it to 0. Should work.But in case if it didn't
Use the Call backs
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}

Adding Menu Item dynamically from SherlockActionBar Fragment Tabs

So I've been working on and Android app that has a Navigation Bar on the top with several Tabs, and that part is working fine but now I want to be able to dynamically add Menu Items to the Action Bar from different Fragments (since some Fragments may have different options available). So far no matter what I've tried I can't seem to get the onCreateOptionsMenu to be called. Here's what I have so far
//First I have a holder class that is used to navigate between the different Fragment Tabs
public class ActionHolder extends SherlockFragmentActivity implements ActionBar.TabListener {....
//And then I have this method for switching Fragments based on what Tab is selected
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
int selectedTab = tab.getPosition();
if (selectedTab == 0) {
SalesMainScreen salesScreen = new SalesMainScreen();
ft.replace(R.id.content, salesScreen);
}
else if (selectedTab == 1) {
ClientMainScreen clientScreen = new ClientMainScreen();
ft.replace(R.id.content, clientScreen);
}.....
Now here is one of the Tab's Fragments (the SalesMainScreen) that I want to have a few menu items added to the Action Bar
#Override
public void onCreate (Bundle savedInstanceState) {
Log.i("message","the oncreate method was called");
setHasOptionsMenu(true);
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup group, Bundle saved) {
return inflater.inflate(R.layout.salesmainscreen, group, false);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
Log.i("message", "the oncreatemenu method called");
inflater.inflate(R.menu.menu_refresh, menu);
super.onCreateOptionsMenu(menu, inflater);
}
I see the OnCreate Log message being called but I don't see the onCreateOptionsMenu Log being called at all. Also, I know that sometimes the imports cause issues, but when I import the Sherlock Menu and Menu Inflater I get all kinds of error messages on the OnCreateOptionMenu method about them not being compatible. Is it possible in this setup to dynamically add Menu Items to the Action Bar, or should I just add the items and then just don't do any actions on the ones that don't apply to the fragment that is being displayed?

I have an app using SherlockActionBar and tabs, with each tab containing a SherlockFragment. The main activity has its own menu in the action bar, and one of the fragments adds a search item to the action bar menu.
The main activity has the following:
class MainActivity extends SherlockFragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
ActionBar bar = getSupportActionBar();
bar.addTab(createThingOneTab());
bar.addTab(createThingTwoTab());
bar.addTab(createThingThreeTab());
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getSupportMenuInflater().inflate(R.menu.activity_main, menu);
}
}
The fragment in the tab has the following:
class ThingOneFragment extends SherlockFragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
setHasOptionsMenu(true);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
MenuItem search = menu.add("Search");
search.setIcon(android.R.drawable.ic_menu_search);
search.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
...
}
}
When I start the main activity, the tab shows ThingOneFragment by default and I see the search icon in the action bar. When I select the other tabs, the search icon disappears. You do need to make sure that you are using the Sherlock classes for Menu, MenuInflater, etc.
I'm not sure if it makes a difference but my TabListener looks like this:
private TabListener createTabListener(final Class<? extends Fragment> clazz) {
return new TabListener() {
private Fragment mFragment;
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// no action
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mFragment == null) {
mFragment = Fragment.instantiate(activity, clazz.getName());
}
getSupportFragmentManager().beginTransaction()
.replace(android.R.id.content, mFragment)
.commit();
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// no action
}
};
I'm not sure if that is causing your issue or if it's even the correct way of handling tabs but I include it for completeness.

Overlaid widgets in fragments after orientation change

In my Android app I'm using an Action Bar with tabs to switch between fragments that display the content of the tabs. Everything is working fine until an orientation change: Then Android starts to draw the widgets on top of each other so that the contents of the fragments get mixed up. My TabListener:
private class TabListener implements ActionBar.TabListener {
private final Activity mActivity;
private final String mTag;
public TabListener(Activity activity, String tag) {
mActivity = activity;
mTag = tag;
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
Fragment mFragment = MyActivity.this.getSupportFragmentManager().findFragmentByTag(mTag);
if (mFragment == null) {
mFragment = new MyFragment();
ft.add(android.R.id.content, mFragment, mTag);
} else {
ft.attach(mFragment);
}
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
Fragment mFragment = MyActivity.this.getSupportFragmentManager().findFragmentByTag(mTag);
if (mFragment != null) {
ft.detach(mFragment);
}
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
// Do nothing
}
}
The only thing I noticed was that on every orientation change, onTabUnselected() won't be called, but still onTabSelected() is called (so the current tab will be attached twice without being detached in between). If that's the problem, I do not know how to fix it. If that's not the problem, I do not know where to look. I would be glad if someone has a suggestion.
Sidenote: I'm using the Action Bar from ActionBarSherlock. The problem appears on all Android versions I tested with (2.3, 4.0, 4.1).

I am not sure but here are some steps you can follow
Take Bundle reference before your Activity onCreate() method.
Bundle b1;
In your onCreate() method , put the Bundle value in b1
#Override
public void onCreate(Bundle savedInstanceState) {b1=savedInstanceState;
............................
}
Use this b1 in your onTabSelected method as
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
Fragment mFragment = MyActivity.this.getSupportFragmentManager().findFragmentByTag(mTag);
if (b1!=null){
ft.detach(mFragment);
//and the rest code
................}
}
Its an conclusion , which I have concluded with my working with fragments, but I have not done it with TabListener. So tell me when you are done , or any other solution.

Run code in ActionBar Tab Fragment when tab is removed

I've got Fragment ActionBar Tabs with an TabListener attached to every tab. In my main activity I got a delete tab button as follows:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()
case R.id.closeTab:
closeTab();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void closeTab() {
if(getActionBar().getTabCount() > 1) {
Tab tab = getActionBar().getSelectedTab();
getActionBar().removeTab(tab);
}
}
What I'm trying to accomplish is to run some code in my tab-fragment before it gets removed. I could place this in the fragments onDestroyView() or onDestroy() but I only whant to run this code when I press my delete tab button.
I have checked the documentation for the TabListener but it seems like TabListener only listens to selectionchanges.
My TabListener:
public TabListener(Activity a, String t, Class<T> c) {
activity = a;
tag = t;
myClass = c;
}
/* The following are each of the ActionBar.TabListener callbacks */
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (fragment == null) {
// If not, instantiate and add it to the activity
fragment = Fragment.instantiate(activity, myClass.getName());
ft.add(android.R.id.content, fragment, tag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(fragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (fragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(fragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
To clarify my question: How can I run code in my Fragment before the tab is removed?

Okey, I figured it out after reading this post: link.
In my fragment I put setHasOptionMenu(true)
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setHasOptionsMenu(true);
}
And then I could just add onOptionsItemSelected in my fragment.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.closeTab:
closeTab();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void closeTab() {
ActionBar actionBar = getActivity().getActionBar();
if(actionBar.getTabCount() > 1) {
Tab tab = actionBar.getSelectedTab();
actionBar.removeTab(tab);
Log.d(TAG, "CLOSED TAB");
}
}