Develop Reference

Fragment wont start - called from Activity

I'm trying to start a fragment from my main activity, but somehow the fragment is not showing up. Can someone help me with this?
Here is my code:
public class Main extends Activity implements OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button b = (Button) findViewById(R.id.action_menu);
b.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if(v.getId()==R.id.action_menu){
Log.d("--", "menu clicked");
MenuFragment newFragment = new MenuFragment();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack
transaction.replace(android.R.id.content, newFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
}
}
main activity layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/main_rl" >
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="#+id/action_menu" android:text="Menu"/>
</RelativeLayout>
and my fragment Class:
public class MenuFragment extends Fragment{
final String TAG=this.getClass().getSimpleName();
private GridView grid;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View mView;
Log.d(TAG, "Hello from Fragment");
mView=inflater.inflate(R.layout.menu_fullscreen, null);
initWidgets(mView);
return mView;
}
private void initWidgets(View mView) {
grid=(GridView) mView.findViewById(R.id.menu_fullscreen_grid);
}
}

you cannot replace what you put in setContentView(R.layout.main); if main.xml is hardCoded...(xml file). with
transaction.replace...
You may use fragmentActivity without setContentView(R.layout.main)

FragmentManager not calling onCreateView with second tab after orientation change

I have 3 fragments in TabA, and a PreferenceFragment in TabB. To recreate the problem I start the program, TabA displays fine. I click TabB and it also displays fine. If I return to TabA, and do an orientation change, the next time I click on TabB there is just a blank screen. I've narrowed it down to the FragmentManager not calling onCreateView on the Fragment in TabB.
I'm checking that the Fragments are not null and don't need to be recreated and getting references to them with their findFragmentByTag after orientation changes. TabA never has an issue, i tried to recreate the issue with TabA but onCreateView would always get called by the FragmentManager for each Fragment. I have min API 15, target 19.
Pruned down version of MyActivity.java to be runnable
public class MyActivity extends Activity {
private static final String TAG = "MainActivity";
public FragmentManager fm;
#Override
protected void onCreate(Bundle savedInstanceState) {
Log.d(TAG, "onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_master);
fm = getFragmentManager();
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tabA = actionBar.newTab().setText("Main");
ActionBar.Tab tabB = actionBar.newTab().setText("Settings");
tabA.setTabListener(new TabAListener(this));
actionBar.addTab(tabA);
tabB.setTabListener(new TabBListener(this));
actionBar.addTab(tabB);
if (savedInstanceState != null) {
int index = savedInstanceState.getInt("index");
actionBar.setSelectedNavigationItem(index);
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
Log.d(TAG, "onSaveInstanceState");
super.onSaveInstanceState(outState);
int i = getActionBar().getSelectedNavigationIndex();
outState.putInt("index", i);
}
public class TabAListener implements ActionBar.TabListener {
private static final String genTag = "GenerateFragment";
private static final String aboutTag = "AboutFragment";
public static final String resultsTag = "ResultsListFragment";
private ArrayList<Fragment> fragList;
public TabAListener(Activity activity) {
fragList = null;
}
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
// Reselected don't do anything
Log.d(TAG, "Tab A: on Tab reselected");
}
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.d(TAG, "Tab A: on Tab Selected");
// attach all the fragments
if (fragList == null) {
fragList = new ArrayList<Fragment>();
TestFragment genFrag;
if (fm.findFragmentByTag(genTag) == null) {
genFrag = new TestFragment();
ft.add(R.id.gen_fragment, genFrag, genTag);
} else genFrag = (TestFragment) fm.findFragmentByTag(genTag);
TestFragment aboutFrag;
if (fm.findFragmentByTag(aboutTag) == null) {
aboutFrag = new TestFragment();
ft.add(R.id.about_fragment, aboutFrag, aboutTag);
} else aboutFrag = (TestFragment) fm.findFragmentByTag(aboutTag);
TestFragment resultsFrag;
if (fm.findFragmentByTag(resultsTag) == null) {
resultsFrag = new TestFragment();
ft.add(R.id.results_fragment, resultsFrag, resultsTag);
} else {
resultsFrag = (TestFragment) fm.findFragmentByTag(resultsTag);
}
fragList.add(genFrag);
fragList.add(aboutFrag);
fragList.add(resultsFrag);
Log.d(TAG, "Tab A: Added fragments to the ArrayList");
} else {
Iterator iter = fragList.iterator();
while (iter.hasNext()) {
Log.d(TAG, "Tab A: Attaching fragments");
ft.attach((Fragment) iter.next());
}
}
}
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.d(TAG, "Tab A: on Tab Unselected");
if (fragList != null) {
Iterator iter = fragList.iterator();
while (iter.hasNext()) {
Log.d(TAG, "Tab A: Fragments detached");
ft.detach((Fragment) iter.next());
}
}
}
}
public class TabBListener implements ActionBar.TabListener {
private static final String settingsTag = "SettingsFragment";
private ArrayList<Fragment> fragList;
public TabBListener(Activity activity) {
fragList = null;
}
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
// Reselected don't do anything
Log.d(TAG, "Tab B: on Tab reselected");
}
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.d(TAG, "Tab B: on Tab Selected");
// attach all the fragments
if (fragList == null) {
fragList = new ArrayList<Fragment>();
TestFragment settingsFrag;
if (fm.findFragmentByTag(settingsTag) == null) {
settingsFrag = new TestFragment();
ft.add(R.id.frame_main, settingsFrag, settingsTag);
} else {
Log.d(TAG, "Tab B: not null");
settingsFrag = (TestFragment) fm.findFragmentByTag(settingsTag);
}
fragList.add(settingsFrag);
Log.d(TAG, "Tab B: Added fragments to the ArrayList");
} else {
Iterator iter = fragList.iterator();
while (iter.hasNext()) {
Log.d(TAG, "Tab B: Attaching fragments");
ft.attach((Fragment) iter.next());
}
}
}
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.d(TAG, "Tab B: on Tab Unselected");
if (fragList != null) {
Iterator iter = fragList.iterator();
while (iter.hasNext()) {
Log.d(TAG, "Tab B: Fragments detached");
ft.detach((Fragment) iter.next());
}
}
}
}
public static class TestFragment extends Fragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
return inflater.inflate(R.layout.fragment_text, container, false);
}
}
}
activity_master.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/frame_main"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="3"
android:orientation="vertical">
<FrameLayout
android:id="#+id/gen_fragment"
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1" />
<FrameLayout
android:id="#+id/about_fragment"
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1" />
</LinearLayout>
<FrameLayout
android:id="#+id/results_fragment"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="2" />
</LinearLayout>
</FrameLayout>
fragment_text.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="test" />
</LinearLayout>

So, I guess I have to remove the super call in MainActivity.onSaveInstanceState in order for onCreateView to be called correctly for TabB's fragment after an orientation change. Umm, I'm not sure why that works so could someone explain why?
I've been able to gather that the super.onSaveInstanceState saves the activities views for when the user navigates away from the application and eventually returns. And the FragmentManager also has responsibility for the contents of the fragment through orientation changes. I'm kind of lost at that point.

Updating ui in a fragment

I can't seem to update the ui in one of my fragments, I'm not sure why. I have a main activity which should send some json to the fragment and update the UI with the data from the JSON object. I'm sending the json over successfully and I can log the data in the Fragment which I have sent over. I am just not able to update the textbox value in the UI.
In my mainactivity
MainPageFragment myFragment = new MainPageFragment();
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Create adapter that will return a fragment for each section of app
mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
#Override
public void onSuccess(JSONObject user) {
//This seems to be all I need
myFragment.grabJSON(user);
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle (int position) {
return titles[position];
}
#Override
public Fragment getItem(int position) {
if (position == 1) {
return new PreferenceFragment() {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.layout.settings_preferances);
}
};
}
else {
return myFragment;
}
}
}
In my MainFragment.java
public void grabJSON(JSONObject object){
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
TextView usernameTextView = (TextView) getView().findViewById(R.id.usernameview);
CharSequence val = usernameTextView.getText();
Log.d("value", val.toString());
usernameTextView.setText("NEW TEXT");//Set the Text
val = usernameTextView.getText();
Log.d("value", val.toString());
}
});
}
The fact that it sends the json is irrelevant, according to the log, my value of the textbox is changing but the actual UI is not changing.
I'm adding here the xml for the mainactivity
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<android.support.v4.view.PagerTabStrip
android:id="#+id/pager_header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:textColor="#fff"/>
<FrameLayout
android:id="#+id/fragment_placeholder"
android:layout_width="fill_parent"
android:layout_height="fill_parent" ></FrameLayout>
</android.support.v4.view.ViewPager>
This has been updated with correct code, turns out I was defining the fragment twice
Thank you all,
Tom

Your fragment is getting added twice.
It's added via the layout XML file, and then you do a fragment transaction to add it aw well. Adding fragments via layout doesn't work as well as it should, so you should put in a placeholder view and then add the fragment via the fragment manager. That should clear everything up.

I'm guessing you dont add the fragment in the activity?
FragmentManager fragmentManager = getFragmentManager()
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
MainPageFragment fragment = new MainPageFragment ();
fragmentTransaction.add(R.id.fragment_container, fragment);
fragmentTransaction.commit();

How to show ListView in Tab?

I want to display ListView in Tab (after selecting this tab I want ListView to appear),so I have created Fragment class and placed ListView code in it.The main problem now is to pass fragment object to tabListener. Please, post here example, or even better show how to do that in my code. Anyway, any help will be appreciated.
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tabOne = actionBar.newTab().setText("One");
ActionBar.Tab tabTwo = actionBar.newTab().setText("Two");
tabOne.setTabListener(new tabListener());
tabTwo.setTabListener(new tabListener());
actionBar.addTab(tabOne);
actionBar.addTab(tabTwo);
}
protected class tabListener implements ActionBar.TabListener {
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
};
public class FirstFragment extends ListFragment {
private ArrayList<Cinemas> cinema;
private CinemasAdapter cinemaAdapter;
private ListView list;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
cinema = new Handler().handle();
cinemaAdapter = new CinemasAdapter(MainActivity.this, R.layout.movie_data_row, cinema);
setListAdapter(cinemaAdapter);
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
Cinemas movie = cinemaAdapter.getItem(position);
Intent intent = new Intent (MainActivity.this, More.class);
intent.putExtra("Cinemas", movie);
intent.putExtra("data", movie.getBitmap());
Bundle translateBundle =
ActivityOptions.makeCustomAnimation(MainActivity.this,
R.anim.slide_in_left, R.anim.slide_out_left).toBundle();
startActivity (intent, translateBundle);
}
}
}

If you want to open up the list inside the tabTwo, you will need to create an instance of the FirstFragment class and add it to your view when you select the tab. Inside onTabSelected, create a new instance of FirstFragment if it isn't null, and add it to your view inside a container in your activity_main file. A container is a linear layout inside the view with the given amount of space that should be occupied by the fragment. In the case of a fullscreen fragment, the container is the root layout. You need only to specify an id to this layout. Once you create a new fragment, attach it by calling transaction.attach(); The final code block should be similar to this:
/** this example assumes that the fragment
* FirstFragment will be attached to tab 1
* which is at position = 0, and SecondFragment
* will be attached to tab 2, which is at
* position = 1. Also, the root layout of
* activity_main.xml has the id attribute of
* fragment_container
*/
FirstFragment firstFragment;
SecondFragment secondFragment;
#Override
public void onTabSelected(Tab tab, FragmentTransaction transaction) {
switch (tab.getPosition()) {
case 0:
if (firstFragment == null) {
firstFragment = new FirstFragment();
transaction.add(R.id.fragment_container,
firstFragment, "FIRST");
} else {
transaction.attach(firstFragment);
}
break;
case 1:
if (secondFragment == null) {
secondFragment = new SecondFragment();
transaction.add(R.id.fragment_container, secondFragment, "SECOND");
} else {
transaction.attach(secondFragment);
}
break;
}
}

Changing an activities content view based on actionbar tabs

I am wondering if this can be done. Basically I have a layout with 2 fragments in it that I use for most of my tabs but on 2 of the tabs I want to add a couple more fragments to display more things. Is it possible to change the content view to a different layout when changing tabs?
If that cant be done I thought about creating a layout with all the fragment parts that I would need and just changing the layouts of the fragments so the ones I dont use wont "show". I dont mean using FragmentTransaction.hide() because I want the fragments to fill the screen when others are not used. Would that be a bad idea or is there an easier way to do what I want?
here is my code for the activity and tabs
public class Tabs extends Activity{
long deleteID;
#Override
public void onCreate(Bundle create){
super.onCreate(create);
setContentView(R.layout.main_layout);
createTabs();
ActionBar bar = getActionBar();
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);
bar.setDisplayHomeAsUpEnabled(true);
if(create != null){
bar.setSelectedNavigationItem(create.getInt("Home",0));
}
}
I also add tabs a whatnot but thats not important
this is the actionbar subclass
private class TabListener implements ActionBar.TabListener{
TabContent mFragment;
public TabListener(TabContent fragment) {
mFragment = fragment;
}
#Override
public void onTabReselected(Tab tab, android.app.FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, android.app.FragmentTransaction ft) {
ListFragment newListFragment = new BowlersListFragment();
Fragment newFragment = new BowlerEntryFrag();
ft = getFragmentManager().beginTransaction();
ft.replace(R.id.frameOne, newListFragment);
ft.replace(R.id.frameTwo, newFragment);
ft.addToBackStack(null);
ft.commit();
}
#Override
public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {
if(ft != null){
ft.remove(mFragment);
}
}
}
}
I tried doing Activity.setContentView(r.layout.newView) but that won't work

I had similar problem, so implemented it like this. I have a mainActivity that holds and creates the tabs. That activity uses a layout with one fragment container, main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
In my activity I have the following code for creating the tabs and fragments:
historyTab = actionbar.newTab().setText("History");
historyTab.setTabListener(new MyTabsListener(new HistoryFragment()));
actionbar.addTab(historyTab);
My tabListener looks something like this:
private class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
private boolean isFragmentAdded = false;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
#Override
public void onTabSelected(Tab tab, android.app.FragmentTransaction ft) {
FragmentManager fragMgr = getSupportFragmentManager();
FragmentTransaction xaction = fragMgr.beginTransaction();
if (fragment instanceof HistoryFragment) {
fragment = new HistoryFragment();
xaction.add(R.id.fragment_container, fragment);
} else if (fragment instanceof .. some other fragment..) {
fragment = new .. some other fragment();
xaction.add(R.id.fragment_container, fragment);
}
}
xaction.commit();
}
#Override
public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {
FragmentManager fragMgr = getSupportFragmentManager();
FragmentTransaction xaction;
xaction = fragMgr.beginTransaction();
Fragment fragment = fragMgr.findFragmentById(R.id.fragment_container);
xaction.remove(fragment);
xaction.commit();
}
}
The layout for the History fragment in my example, can be anything, even a layout that contains two fragments, or as much you need. Just be careful, and in onCreateview method in the fragment, use this:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle
savedInstanceState) {
if (view == null) { // this line is very important!
view = inflater.inflate(R.layout.history_fragment_layout, container, false);
listView = (ListView) view.findViewById(R.id.historyList);
}
return view;
}
Hope that helps!:)