Develop Reference

Add back button to Toolbar for all Fragments other than Home Fragment which opens Navigation Drawer

When my application is opened Home screen is shown first.On Home screen I have NavigationDrawer which get opened after pressing HamburgerIcon.Later i go to different fragments.When I am in Other fragments other than Home Activity I need to show back button on Toolbar to come to previous fragment.But its every time showing Hamburger icon.How to do this ?
This is code for setting Toolbar in XML
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/drawerLayout"
tools:context="biz.fyra.myApp.ActivityTwo">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#ccc"
android:minHeight="?attr/actionBarSize">
<ImageView
android:id="#+id/tooImage"
android:src="#drawable/latest"
android:layout_width="match_parent"
android:layout_gravity="center_horizontal"
android:layout_height="40dp" />
</android.support.v7.widget.Toolbar>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/frame">
</FrameLayout>
</LinearLayout>
<android.support.design.widget.NavigationView
android:layout_width="300dp"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="#layout/nav_header"
android:id="#+id/navigationView"
app:menu="#menu/actionmenu"
android:background="#android:color/white">
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
How to achieve this ?

If i understand right, you are using one activity with fragments replacing. So, looking at that you would have something like this:
Important: Activity theme should extends Theme.AppCompat.Light.NoActionBar
Activity:
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private DrawerLayout drawer;
private Toolbar toolbar;
private ActionBarDrawerToggle toggle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
drawer = findViewById(R.id.drawer);
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
toggle = new ActionBarDrawerToggle(
this,
drawer,
toolbar,
R.string.navigation_drawer_open,
R.string.navigation_drawer_close
);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
// First creation
if (savedInstanceState == null)
showFragment(StartFragment.newInstance());
}
/**
* Using in Base Fragment
*/
protected ActionBarDrawerToggle getToggle() {
return toggle;
}
#Override
public void onBackPressed() {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.frame);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else if (fragment instanceof OnBackPressedListener) {
((OnBackPressedListener) fragment).onBackPressed();
} else {
super.onBackPressed();
}
}
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
drawer.closeDrawer(GravityCompat.START);
switch (item.getItemId()) {
case R.id.start: {
showFragment(StartFragment.newInstance());
break;
}
case R.id.orders: {
showFragment(OrdersFragment.newInstance());
break;
}
case R.id.category: {
showFragment(CategoryFragment.newInstance());
break;
}
case R.id.calendar: {
showFragment(CalendarFragment.newInstance());
break;
}
case R.id.settings: {
showFragment(SettingsFragment.newInstance());
break;
}
case R.id.about: {
showFragment(AboutFragment.newInstance());
break;
}
return true;
}
private void showFragment(Fragment fragment) {
getSupportFragmentManager().beginTransaction().replace(R.id.frame, fragment).commit();
}
}
Interface for sending backpress events from activity to fragments:
public interface OnBackPressedListener {
void onBackPressed();
}
And Abstract Base Fragment which you should extends and implement methods:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import ...
/**
* Abstract fragment with FAB button, Toolbar and 2 interfaces:
OnClick, OnBackPress
*
*/
public abstract class BaseFragment extends Fragment implements
View.OnClickListener, OnBackPressedListener {
protected FloatingActionButton fab;
protected Toolbar toolbar;
protected ActionBar actionBar;
protected ActionBarDrawerToggle toggle;
protected DrawerLayout drawer;
protected boolean mToolBarNavigationListenerIsRegistered = false;
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
fab = ((MainActivity)getActivity()).findViewById(R.id.fab);
toolbar = ((MainActivity) getActivity()).findViewById(R.id.toolbar);
actionBar = ((MainActivity) getActivity()).getSupportActionBar();
drawer = ((MainActivity) getActivity()).findViewById(R.id.drawer_layout);
toggle = ((MainActivity) getActivity()).getToggle();
fab.setOnClickListener(this);
}
/**
* Simplify fragment replacing in child fragments
*/
protected void replaceFragment(#NonNull Fragment fragment) {
FragmentManager fm = getActivity().getSupportFragmentManager();
fm.beginTransaction().replace(R.id.container, fragment).commit();
}
// hide FAB button
protected void hideFab() {
fab.hide();
}
//show FAB button
protected void showFab() {
fab.show();
}
/**
* Shows Home button as Back button
* Took from here {#link}https://stackoverflow.com/a/36677279/9381524
* <p>
* To keep states of ActionBar and ActionBarDrawerToggle synchronized,
* when you enable on one, you disable on the other.
* And as you may notice, the order for this operation is disable first, then enable - VERY VERY IMPORTANT!!!
*
* #param show = true to show <showHomeAsUp> or show = false to show <Hamburger> button
*/
protected void showBackButton(boolean show) {
if (show) {
// Remove hamburger
toggle.setDrawerIndicatorEnabled(false);
// Show back button
actionBar.setDisplayHomeAsUpEnabled(true);
// when DrawerToggle is disabled i.e. setDrawerIndicatorEnabled(false), navigation icon
// clicks are disabled i.e. the UP button will not work.
// We need to add a listener, as in below, so DrawerToggle will forward
// click events to this listener.
if (!mToolBarNavigationListenerIsRegistered) {
toggle.setToolbarNavigationClickListener(v -> onBackPressed());
mToolBarNavigationListenerIsRegistered = true;
}
} else {
// Remove back button
actionBar.setDisplayHomeAsUpEnabled(false);
// Show hamburger
toggle.setDrawerIndicatorEnabled(true);
// Remove the/any drawer toggle listener
toggle.setToolbarNavigationClickListener(null);
mToolBarNavigationListenerIsRegistered = false;
}
// So, one may think "Hmm why not simplify to:
// .....
// getSupportActionBar().setDisplayHomeAsUpEnabled(enable);
// mDrawer.setDrawerIndicatorEnabled(!enable);
// ......
// To re-iterate, the order in which you enable and disable views IS important #dontSimplify.
}
/**
* Simplify setTitle in child fragments
*/
protected void setTitle(int resId) {
getActivity().setTitle(getResources().getString(resId));
}
//
#Override
public abstract void onClick(View v);
// Handles BackPress events from MainActivity
#Override
public abstract void onBackPressed();
}
All fragments with Back Button used in MainActivity should extends from this BaseFragment.

You can try something like
#Override
protected void onCreate(Bundle savedInstanceState)
{ super.onCreate(savedInstanceState);
[...]
if (getSupportActionBar() != null)
{ getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
}
[...]
}
#Override
public boolean onOptionsItemSelected(MenuItem item)
{ if (getSupportFragmentManager().getBackStackEntryCount() > 0)
{ switch (item.getItemId())
{ case android.R.id.home:
onBackPressed();
return true;
}
}
[...]
}

What should I define in the setContentView in MainActivity.java file?

I want to know what should come in the bolded part below.It shows me two options:
1.toolbar(The xml I created to add the code for the google appbar)
2.activity_main
The both seems to show no errors that why I want to know which one should I add.
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.**toolbar**);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
}
}

hi add like this,
public class YourActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.youractivity);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(R.id.toolbar_title);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayUseLogoEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayShowTitleEnabled(true);
mTitle.setText("Contact Us");
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}
}
<include
android:id="#+id/toolbar"
layout="#layout/toolbar" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</RelativeLayout>
hope this will help you

As Bansal mentioned correctly, you must use activity_main in setContentView.
Your activity_main.xml will contain the toolbar. Inside the toolbar tag you must call the toolbar layout. It uses your toolbar.xml layout for your toolbar.

Set toolbar for all Activities [duplicate]

This question already has answers here:
Use Toolbar across all activities (Android)
(2 answers)
Closed 2 years ago.
In my app I would like to make a unique toolbar for all activities except for mainActivity.
I have written this code for set Title and logo, but in toolbar I also have username logged.
So I have written in my dashboard activity this code:
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);
assert myToolbar != null;
myToolbar.setLogo(R.mipmap.logo_big);
TextView usernameField = (TextView) findViewById(R.id.username);
try {
usernameField.setText(User.getInstance().getUsername());
} catch (JSONException e) {
e.printStackTrace();
}
And I made a layout that can be included in all xml files.
But How can I reuse this code in all my activities without copy and paste?
Is it wrong to make a singleton? or a utility class?
Thanks

You could create a base activity that runs the common code and have all other activities inherit from it:
// the base class
public abstract class BaseActivity extends AppCompatActivity
{
protected final void onCreate(Bundle savedInstanceState, int layoutId)
{
super.onCreate(savedInstanceState);
setContentView(layoutId);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);
assert myToolbar != null;
myToolbar.setLogo(R.mipmap.logo_big);
TextView usernameField = (TextView) findViewById(R.id.username);
try {
usernameField.setText(User.getInstance().getUsername());
} catch (JSONException e) {
e.printStackTrace();
}
}
}
// inheriting activity
public class SomeActivity extends BaseActivity
{
protected final void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState, R.layout.some_layout);
}
}

keep your code in one CustomActivity.
Where every required in your application extends CustomActivity .
Example:
CustomActivity extends Activity{
// your toolbar code
}
In your all activities extends CustomActivity.

Create a new activity called CustomActivity and a corresponding layout called activity_custom.xml :
<android.support.v4.widget.DrawerLayout
android:id="#+id/activity_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
android:background="#color/background_material_dark"
/>
<FrameLayout
android:id="#+id/activity_content"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
<android.support.design.widget.NavigationView
android:id="#+id/navigationView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="#menu/menu_base"/>
Open BaseActivity.java and make sure to remove setContentView(R.layout.activity_base) from the onCreate() method. and override the setContentView() method with your own implementation:
#Override
public void setContentView(int layoutResID) {
DrawerLayout fullView = (DrawerLayout) getLayoutInflater().inflate(R.layout.activity_base, null);
FrameLayout activityContainer = (FrameLayout) fullView.findViewById(R.id.activity_content);
getLayoutInflater().inflate(layoutResID, activityContainer, true);
super.setContentView(fullView);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setTitle("Activity Title");
}
In your all activities extends CustomActivity.

You can do like this:
class BaseActivity extends AppCompatActivity
{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public void initToolbar(int toolbarId)
{
Toolbar myToolbar = (Toolbar) findViewById(toolbarId);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);
assert myToolbar != null;
myToolbar.setLogo(R.mipmap.logo_big);
}
}
class YourActivity extends BaseActivity
{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(your activity layout);
initToolbar(R.id.yourToolbarId);
}
}

Adding toolbar to PreferenceActivity via AppCompatPreferenceActivity causes overlapping

I had gone through How to add toolbars to AppCompatPreferenceActivity?
I'm using appcompat-v7:23.0.1 and support-v4:23.0.1
Before using AppCompayPreferenceActivity, my PreferenceActivity looks the following without toolbar.
Without Toolbar
public class JStockPreferenceActivity extends PreferenceActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
// Display the fragment as the main content.
JStockPreferenceFragment jStockPreferenceFragment = JStockPreferenceFragment.newInstance();
jStockPreferenceFragment.setArguments(this.getIntent().getExtras());
this.getFragmentManager().beginTransaction().replace(android.R.id.content, jStockPreferenceFragment).commit();
}
}
After using AppCompayPreferenceActivity, with some Toolbar initialization code, the outcome looks as the following
The outcome isn't as expected :-
The Toolbar overlaps with PreferenceFragment
When touching on Toolbar, the event will be consumed by PreferenceFragment. This means, when you touch on toolbar, "Table header" preference will be touched instead.
With Toolbar
public class JStockPreferenceActivity extends AppCompatPreferenceActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
// Display the fragment as the main content.
JStockPreferenceFragment jStockPreferenceFragment = JStockPreferenceFragment.newInstance();
jStockPreferenceFragment.setArguments(this.getIntent().getExtras());
this.getFragmentManager().beginTransaction().replace(android.R.id.content, jStockPreferenceFragment).commit();
}
initToolbar();
}
private void initToolbar() {
Toolbar toolbar;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
ViewGroup root = (ViewGroup) findViewById(android.R.id.list).getParent().getParent().getParent();
toolbar = (Toolbar) LayoutInflater.from(this).inflate(R.layout.toolbar, root, false);
root.addView(toolbar, 0);
} else {
toolbar = null;
}
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
}
My toolbar is
toolbar.xml
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:minHeight="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" >
<!-- android:elevation="4dp" is used due to http://www.google.com/design/spec/what-is-material/elevation-shadows.html#elevation-shadows-elevation-android- -->
</android.support.v7.widget.Toolbar>
I was wondering, what I had did wrong, which causes Toolbar overlapped with PreferenceFragment

After some research and getting advice from Ian Lake, I manage to make it work by
Change from AppCompatPreferenceActivity, to AppCompatActivity+PreferenceFragmentCompat
The following solution is workable for API 10 and above.
JStockPreferenceActivity.java
public class JStockPreferenceActivity extends AppCompatActivity {
#SuppressWarnings("deprecation")
#SuppressLint("NewApi")
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.jstock_preference_activity);
initToolbar();
if (savedInstanceState == null) {
// Display the fragment as the main content.
JStockPreferenceFragment jStockPreferenceFragment = JStockPreferenceFragment.newInstance();
jStockPreferenceFragment.setArguments(this.getIntent().getExtras());
this.getSupportFragmentManager().beginTransaction().replace(R.id.content, jStockPreferenceFragment).commit();
}
}
JStockPreferenceFragment.java
public class JStockPreferenceFragment extends PreferenceFragmentCompat implements SharedPreferences.OnSharedPreferenceChangeListener, PreferenceFragmentCompat.OnPreferenceDisplayDialogCallback {
public static JStockPreferenceFragment newInstance() {
return new JStockPreferenceFragment();
}
However, by doing so, there is a shortcoming. Your previous custom DialogPreference no longer work. To solve this, you need to
Replace DialogPreference with PreferenceDialogFragmentCompat.
Replace DialogPreference in XML with ListPreference. (I'm not exactly sure whether ListPreference as replacement is a right way. It works anyway)
Manually show PreferenceDialogFragmentCompat, in PreferenceFragmentCompat's onPreferenceDisplayDialog.
JStockPreferenceFragment.java
public class JStockPreferenceFragment extends PreferenceFragmentCompat implements SharedPreferences.OnSharedPreferenceChangeListener, PreferenceFragmentCompat.OnPreferenceDisplayDialogCallback {
public static JStockPreferenceFragment newInstance() {
return new JStockPreferenceFragment();
}
////////////////////////////////////////////////////////////////////////////////////////////////
// Showing custom dialog preference.
private void showPreferenceDialogFragmentCompat(PreferenceDialogFragmentCompat preferenceDialogFragmentCompat) {
preferenceDialogFragmentCompat.setTargetFragment(this, 0);
preferenceDialogFragmentCompat.show(this.getFragmentManager(), "android.support.v7.preference.PreferenceFragment.DIALOG");
}
private void showCurrencySymbolPreferenceDialogFragmentCompat(Preference preference) {
CurrencySymbolPreferenceDialogFragmentCompat currencySymbolPreferenceDialogFragmentCompat = CurrencySymbolPreferenceDialogFragmentCompat.newInstance(preference.getKey());
showPreferenceDialogFragmentCompat(currencySymbolPreferenceDialogFragmentCompat);
}
// Showing custom dialog preference.
////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////
// Callback when we are using custom dialog preference.
#Override
public Fragment getCallbackFragment() {
return this;
}
#Override
public boolean onPreferenceDisplayDialog(PreferenceFragmentCompat preferenceFragmentCompat, Preference preference) {
final String key = preference.getKey();
if (_CURRENCY_SYMBOL_OPTIONS.equals(key)) {
showCurrencySymbolPreferenceDialogFragmentCompat(preference);
return true;
}
return false;
}
// Callback when we are using custom dialog preference.
////////////////////////////////////////////////////////////////////////////////////////////////
CurrencySymbolPreferenceDialogFragmentCompat.java
public class CurrencySymbolPreferenceDialogFragmentCompat extends PreferenceDialogFragmentCompat {
public CurrencySymbolPreferenceDialogFragmentCompat() {
}
public static CurrencySymbolPreferenceDialogFragmentCompat newInstance(String key) {
CurrencySymbolPreferenceDialogFragmentCompat fragment = new CurrencySymbolPreferenceDialogFragmentCompat();
Bundle b = new Bundle(1);
b.putString("key", key);
fragment.setArguments(b);
return fragment;
}
#Override
public void onDialogClosed(boolean positiveResult) {
if (positiveResult) {
...
this.getPreference().setSummary(getSummary());
...
}
}
}
preferences.xml
<android.support.v7.preference.ListPreference
android:title="#string/preference_currency_symbol_title"
android:key="_CURRENCY_SYMBOL_OPTIONS" />
Please note that, you need to add the following item in your theme.
<item name="preferenceTheme">#style/PreferenceThemeOverlay</item>
Some bugs regarding theme
However, the theme-ing isn't perfect yet - PreferenceFragmentCompat requires preferenceTheme to be set
This is a known issues : https://code.google.com/p/android/issues/detail?id=183376
There is proposed workaround https://stackoverflow.com/a/32108439/72437 But, the workaround will only work for v14 and above, not v7 and above.

How to maintain ListView fragment state after orientation/configuration change?

I have a ListView fragment in my application that is experiencing some issues.
When I scroll to a specific element in the list view, then rotate the device, the list view resets to the top of the list.
When I enter multi-select mode in the list view, then rotate the device, the selected list items reset.
Here is my activity:
public class TestActivity extends ActionBarActivity
{
protected static final String FRAGMENT_TAG = "TEST";
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FragmentManager fm = getFragmentManager();
TestFragment f = (TestFragment)fm.findFragmentByTag(FRAGMENT_TAG);
// If no fragment exists, then create a new one and add it!
if (f == null)
{
fm.beginTransaction().add(R.id.fragment_holder, new TestFragment(), FRAGMENT_TAG)
.commit();
}
}
}
here is main_layout.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize" >
</android.support.v7.widget.Toolbar>
<FrameLayout
android:id="#+id/fragment_holder"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
Here is my TestFragment class, with the misc. content removed:
public class TestFragment extends ListFragment
{
#Override
public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState)
{
super.onViewCreated(view, savedInstanceState);
// Sets the list up for multiple choice selection.
ListView listView = getListView();
listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
listView.setMultiChoiceModeListener(this);
}
}
I have seen two discussions for this. One is stating that I should be using setRetainInstance(true) in the fragment's onCreate(Bundle savedInstanceState) method. The other says I should be using the onSaveInstanceState(Bundle bundle) and onRestoreInstanceState(Bundle bundle) methods to keep track of stuff somehow. I would like to use the setRetainInstanceState(true) approach, but adding that into the project like so:
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setRetainInstanceState(true);
}
Does not work for me. What am I doing wrong here?

I would suggest a slightly different approach to adding a Fragment to your Activity.
In your TestActivity class, check if the Bundle is null in the onCreate() method. Only add the Fragment if savedInstanceState is null. This will prevent your Activity from adding another instance of the same Fragment when the device's orientation is changed.
public class TestActivity extends ActionBarActivity {
protected static final String FRAGMENT_TAG = "TEST";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (savedInstanceState == null) {
getFragmentManager().beginTransaction()
.replace(R.id.fragment_holder, new TestFragment(), FRAGMENT_TAG)
.commit();
}
}
}
I would suggest not using the setRetainInstance(true) method for a Fragment that has a UI. Check the StackOverflow discussion here for an explanation of when to use setRetainInstance(true).