PROBLEM FOUND:
Behavior was caused by having some left over library project imports. Specifically ActionBarSherlock and SlidingMenuLibrary, neither of which were being used.
Strange problem.
FragmentStatePagerAdapter seems to be instantiating every fragment and then destroying them on a page swipe. (i.e. instantiate all 100 fragments, and destroying the unwanted 97) Just seeing if anyone has seen these symptoms before?
Having just been through debugging the ListView with multiple calls to getView caused by layout problems I thought there may be something similar here? Anyone has some quick ideas before I start debugging properly?
thanks
UPDATE. Attached a simple working version of what I was trying to do... so it shows that it is feasible. Now just need to debug my unwieldy version of my main code :-( Must have done something stupid.
public class MainActivity extends FragmentActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mPlanetTitles;
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
mPlanetTitles = getResources().getStringArray(R.array.planets_array);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
// and now setup the viewpager
mViewPager = (ViewPager)findViewById(R.id.view_pager);
mViewPager.setAdapter(new ContentPagerAdapter(getSupportFragmentManager()));
// sets up the lhs and rhs fragments
if (savedInstanceState == null) {
selectItem(0);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch(item.getItemId()) {
case R.id.action_websearch:
// create intent to perform web search for this planet
Intent intent = new Intent(Intent.ACTION_WEB_SEARCH);
intent.putExtra(SearchManager.QUERY, getActionBar().getTitle());
// catch event that there's no activity to handle intent
if (intent.resolveActivity(getPackageManager()) != null) {
startActivity(intent);
} else {
Toast.makeText(this, R.string.app_not_available, Toast.LENGTH_LONG).show();
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
// update the main content by replacing fragments
// create the lhs and rhs fragments
Fragment lhsFragment = new PlaceHolderFragment();
Bundle args = new Bundle();
args.putString(PlaceHolderFragment.FRAGMENT_TEXT_KEY, mPlanetTitles[position]);
lhsFragment.setArguments(args);
Fragment rhsFragment = new PlaceHolderFragment();
args = new Bundle();
args.putString(PlaceHolderFragment.FRAGMENT_TEXT_KEY, mPlanetTitles[position]);
rhsFragment.setArguments(args);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction().replace(R.id.lhs_fragment, lhsFragment);
ft.replace(R.id.rhs_fragment, rhsFragment);
ft.commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mPlanetTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
// and smooth scroll the viewpager
mViewPager.setCurrentItem(position, true);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
/**
* Fragment that appears in the "content_frame", shows a planet
*/
public static class PlanetFragment extends Fragment {
public static final String ARG_PLANET_NUMBER = "planet_number";
public PlanetFragment() {
// Empty constructor required for fragment subclasses
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_planet, container, false);
int i = getArguments().getInt(ARG_PLANET_NUMBER);
String planet = getResources().getStringArray(R.array.planets_array)[i];
int imageId = getResources().getIdentifier(planet.toLowerCase(Locale.getDefault()),
"drawable", getActivity().getPackageName());
((ImageView) rootView.findViewById(R.id.image)).setImageResource(imageId);
getActivity().setTitle(planet);
return rootView;
}
}
/**
* Simple Place Holder Fragment...
*/
public static class PlaceHolderFragment extends Fragment {
public static final String FRAGMENT_TEXT_KEY = "text_key";
public PlaceHolderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.place_holder_layout, container, false);
String text = getArguments().getString(FRAGMENT_TEXT_KEY);
((TextView)rootView.findViewById(R.id.place_holder_text)).setText(text);
return rootView;
}
}
/**
* FragmentStatePagerAdapter for delivering up the planets for the ViewPAger
*/
private class ContentPagerAdapter extends FragmentStatePagerAdapter {
int mCount;
public ContentPagerAdapter(FragmentManager fm) {
super(fm);
mCount = getResources().getStringArray(R.array.planets_array).length;
}
@Override
public Fragment getItem(int position) {
Log.d("ContentPagerAdapter", "getItem() position: " + position + " called.");
Fragment fragment = new PlanetFragment();
Bundle args = new Bundle();
args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
return mCount;
}
}
}
the main layout
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- As the main content view, the view below consumes the entire
space available using match_parent in both dimensions. -->
<include layout="@layout/content_frames_layout" />
<!-- android:layout_gravity="start" tells DrawerLayout to treat
this as a sliding drawer on the left side for left-to-right
languages and on the right side for right-to-left languages.
The drawer is given a fixed width in dp and extends the full height of
the container. A solid background is used for contrast
with the content view. -->
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
and the content_frames_layout
<!-- RelativeLayout holds the various fragments / ViewPager that hold the content -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<!-- Simple left hand side fragment -->
<FrameLayout
android:id="@+id/lhs_fragment"
android:layout_height="match_parent"
android:layout_width="0px"
android:layout_weight="1" />
<!-- The main view pager -->
<android.support.v4.view.ViewPager
android:id="@+id/view_pager"
android:layout_height="match_parent"
android:layout_width="0px"
android:layout_weight="3" >
</android.support.v4.view.ViewPager>
<!-- simple rhs fragment -->
<FrameLayout
android:id="@+id/rhs_fragment"
android:layout_height="match_parent"
android:layout_width="0px"
android:layout_weight="1" />
</LinearLayout>
