Develop Reference

Activity to Fragment Bundle not being received

UPDATE: This is my current code, however it breaks after I re-click the same button....
Cause: java.lang.IllegalStateException: Fragment already active
I have a main_activity.xml split into Frame layouts.
The upper frame layout contains an edit text and 3 buttons (small, medium, large).
The lower frame layout contains a text view to populate the text of the edit text in either small, medium or large font.
I put the text into a bundle and am attempting to reopen that bundle in the corresponding fragment once the button is clicked.... however, the bundle does not contain any text information from the text according to my debugger.
Here is my code with the medium, large buttons removed
Any help, please?
MainActivity:
public class MainActivity extends AppCompatActivity {
TextView textView;
Button bSmall;
Small fSmall = new Small();
Bundle bundle = new Bundle();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(findViewById(R.id.fragment)!=null){
if(savedInstanceState!=null){
return;
}
}
final EditText editText = (EditText) findViewById(R.id.type_here);
final Button bSmall = (Button)findViewById(R.id.small);
Button bMedium = (Button)findViewById(R.id.medium);
bSmall.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String message_small = editText.getText().toString();
small = message_small;
bundle.putString("message_small", message_small);
fSmall.setArguments(bundle);
FragmentManager fm =getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment, fSmall).commit();
}
});
bMedium.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String message_medium = editText.getText().toString();
bundle.putString("message_medium", message_medium);
fMedium.setArguments(bundle);
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment, fMedium).commit();
}
});
}
public String getMyData(){
return small;
}
}
Small:
public class Small extends Fragment {
EditText editText;
View myView;
public Small() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
myView = inflater.inflate(R.layout.fragment_small, container, false);
Bundle bundle = new Bundle();
bundle = getArguments();
MainActivity activity = (MainActivity)getActivity();
//String dataFromMainActivity = activity.getMyData();
String myString = bundle.getString("message_small");
TextView set = myView.findViewById(R.id.small_text);
set.setText(myString);
// Inflate the layout for this fragment
return myView;
}
}

You forgot to add the bundle to the fragment.
You need to do something like this:
Small fSmall = new Small();
...
bundle.putString("message_small", message_small);
fSmall.setArguments(bundle);
FragmentManager fm =getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment, fSmall);

I think you forgot to add your bundle to your Fragment before calling the fragment manager.
You should try something like this:
Small fSmall = new Small();
Bundle bundle = new Bundle();
bundle.putString("message_small", message_small); //parameters are (key, value).
fSmall.setArguments(bundle);
getSupportFragmentManager().beginTransaction().replace(R.id.fragment, fSmall).commit();
In your second fragment, you should check if myString is not null or empty.
String myString = getArguments().getString("message_small");
if (myString == null) {
Log.e("TAG", "Error: null argument");
}
EDIT I see another problem here. You are accessing varaibles that have not been instatiated. You should inflate your layout before calling findViewById() or it will return a NullPointerException.
Update your Small class like this :
public class Small extends Fragment {
private EditText editText;
View myView;
public Small() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
myView = inflater.inflate(R.layout.fragment_small, container, false);
String myString = getArguments().getString("message_small");
// Here, myView is != null
TextView editText = myView.findViewById(R.id.small_text);
// Here, editText is != null
editText.setText(myString);
return myView;
}
}
Best

Pass data between Activity and Fragment

I want to pass data from Activity to Fragment using Bundle (I used Bundle to passing data between 2 Fragment, and that's worked).
In my Activity I have a ListView, in the OnItemClickListener I want to open a new Fragment, and the Item, which clicked pass through the Activity to this Fragment. But the Item is null, so basically nothing is send to the Fragment.
Here is my Activity:
public class Jegyek extends AppCompatActivity {
View v;
DB mydb;
ListView listView;
private String teszt;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_jegyek);
listView = (ListView)findViewById(R.id.jegyekLista);
mydb = new DB(this);
final ArrayList<String> thelist = new ArrayList<>();
Cursor data = mydb.getTantargynev();
if (data.getCount() == 0) {
Toast.makeText(this, "Nincs jegyek hozzáadva", Toast.LENGTH_SHORT).show();
}
else {
while (data.moveToNext()) {
thelist.add(data.getString(0));
ListAdapter listadapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, thelist);
listView.setAdapter(listadapter);
}
listView.setOnItemClickListener(
new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
teszt = thelist.get(i);
Bundle bundle = new Bundle();
bundle.putString("Tantárgy neve", teszt);
Toast.makeText(Jegyek.this, teszt, Toast.LENGTH_SHORT).show();
Fragment jegyekAllando = new jegyekAllando();
jegyekAllando.setArguments(bundle);
FragmentTransaction FragTan = getSupportFragmentManager().beginTransaction();
FragTan.replace(R.id.jegyekMenu, jegyekAllando);
ListView listaNezet = (ListView) findViewById(R.id.jegyekLista);
listaNezet.setVisibility(View.GONE);
FragTan.commit();
}
}
);
}
}
public String getTanNev () {
System.out.println("WARNING: "+ teszt);
return teszt;
}
}
And my Fragment:
public class jegyekAllando extends Fragment {
DB mydb;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_jegyek_allando, container, false);
Bundle bundle = new Bundle();
String tanNev = bundle.getStrin
g("Tantárgy neve");
Jegyek jegyAct = new Jegyek();
String tanNevv = jegyAct.getTanNev();
mydb = new DB(getActivity());
String jegyAtlag =String.valueOf(mydb.JegyekAtlaga(tanNev));
String jegyDarab =String.valueOf(mydb.JegyekDarabszama(tanNev));
return rootView;
}
}
When I realized, that the bundle is null, I try to pass that List Item through getter, so I changed my Fragment code for that:
Jegyek jegyek = new Jegyek();
String jegy = jegyek.getTanNev();
But that's not solved my problem, so I back to the Bundle, which also have some problem, but I can't find it. Intresting, that in the OnItemClickListener when I Toast the Item it's correct and works, but when I want to display in the console or pass to the Fragment, the value's is null.

From Activity you send data with intent as:
Bundle bundle = new Bundle();
bundle.putString("edttext", "From Activity");
// set Fragmentclass Arguments
Fragmentclass fragobj = new Fragmentclass();
fragobj.setArguments(bundle);
and in Fragment onCreateView method:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
String strtext = getArguments().getString("edttext");
return inflater.inflate(R.layout.fragment, container, false);
}
Hope this helps

Please follow this example:
In your activity, Pass data like
Bundle bundle = new Bundle();
bundle.putString("test", "Test Data");
// set in your testFragment Arguments
TestFragment testFragment = new TestFragment();
testFragment.setArguments(bundle);
And Receive Data from your TestFragment Like
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
String text = getArguments().getString("test");
return inflater.inflate(R.layout.fragment, container, false);
}

In fragment "jegyekAllando" you must get your string from onCreate() with Bundle data = getArguments(), but you create new bundle.

Pass value to fragment

I am creating a app in which i wanna slide images,so for that i will be using view pager.For the image i have created a fragment which will display the images.
Code
public class ImageSwitcher extends BaseFragment {
private ImageView imageView;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.image_switcher_fragment, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
initialize();
}
private void initialize() {
imageView = (ImageView) view.findViewById(R.id.image_switcher);
imageView.setBackgroundResource("");
}
Now at this line
imageView.setBackgroundResource("");
the image will come from the int array which i will pass.
My doubt is
How will i pass int values to fragments
Is there any better way to use image switcher

Pass your Integer value from your fragment using Bundle as below:
Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putInt("id", id);
fragment.setArguments(bundle);
Access the value in Fragment onCreateView method:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
int m_id=getArguments().getInt("id");
return inflater.inflate(R.layout.fragment, container, false);
}

class MyFragment extends Fragment {
private static final String ARG_BG_RES="ARG_BG_RES";
public Fragment() {}
static public newInstance(String backgroundRes) {
Bundle args = new Bundle();
args.putExtra(ARG_BG_RES, backgroundRes);
Fragment fragment = new Fragment();
fragment.setArguments(args);
return f;
void whereYouNeedIt() {
String backgroundRes = getArguments().getStringExtra(ARG_BG_RES);
...
}
}
From outside:
MyFragment f = MyFragment.newInstance("black");
Don't omit public Fragment() {} it's required by the OS.

You can use bundle to pass values to the fragment or during initializing pass values via a custom constructor
For background resource if you are not changing images based on some logic in code, apply it via XML background and a drawable :-/

Accessing Fragment's views after inflating

What I need to achieve
A screen displaying a ListView, which can be replaced by an error screen in case of problems (missing connection, server unavailable and the like).
I need to be able to switch (programmatically) back and forth between these two screens.
Requirements
The main screen must be a Fragment.
This is because my application is composed of several sections, each one accessible from the navigation drawer.
What I have done so far
The main fragment class is named AllQueuesFragment: its XML layout consists of a FrameLayout, which I use in combination with the FragmentManager to switch between ErrorFragment (containing the error message) and QueuesViewFragment (containing the ListView).
public class AllQueuesFragment extends Fragment
{
public AllQueuesFragment()
{
super();
}
#Override
public void onStart()
{
super.onStart();
// Show the right fragment based on connectivity status
checkConnection();
}
public void checkConnection()
{
final NetworkManager netManager = NetworkManager.getInstance(this.getActivity());
if (netManager.isConnected())
showQueues();
else
showNoConnection();
}
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
fragNoConnection.setTitle(R.string.text_no_connection);
fragNoConnection.setIcon(R.drawable.thatfeel);
fragNoConnection.setLoaderVisibility(false);
}
public void showQueues()
{
QueuesViewFragment fragQueuesView = new QueuesViewFragment();
displayFragment(fragQueuesView);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_allqueues, container, false);
return rootView;
}
// Displays a new fragment
public void displayFragment(Fragment fragment)
{
if (fragment != null)
{
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
}
}
}
The error screen is the following:
public class ErrorFragment extends Fragment
{
private TextView textTitle;
public ErrorFragment()
{
super();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
return rootView;
}
// Set methods
public void setTitle(int id) { textTitle.setText(id); }
}
The problem
The setTitle() method gets called before the layout is ready, and as a result, a NullPointerException is thrown.
class AllQueuesFragment
{
....
public void displayFragment(Fragment fragment)
{
if (fragment != null)
{
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
}
}
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
// PROBLEM HERE: Before calling setTitle(), I must be sure that ErrorFragment's
// layout is inflated!
fragNoConnection.setTitle(R.string.text_no_connection);
}
....
}
class ErrorFragment
{
....
public void setTitle(String value) { textTitle.setText(value); }
....
}
I can't call setTitle() directly from ErrorFragment::onCreateView(), because I don't know beforehand which message I need to show.
How can I ensure that fragNoConnection has completed its layouting?
Is there a better way to achieve my goal?
Unsatisfying workaround
The only workaround I can think of is to use a buffer to defer the actual call:
class ErrorFragment
{
// This string will hold the title until the layout is inflated
private String titleBuffer;
private TextView textTitle = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
// Do the actual set
setTitle(titleBuffer);
return rootView;
}
....
public void setTitle(String value)
{
titleBuffer = value;
// If the layout is not inflated, defer the actual set
if (textTitle != null)
textTitle.setText(titleBuffer);
}
....
}
but I don't like this solution very much (the code above is simplified; ErrorFragment has more properties).
Advices?
Thanks in advance

This is exactly the type of thing arguments are supposed to be used for:
public void showNoConnection() {
ErrorFragment fragNoConnection = new ErrorFragment();
Bundle args = new Bundle();
//you can also use putInt here if you'd rather pass a string resource id, along with anything else you can stick into a Bundle
args.putString("title", "some title");
fragNoConnection.setArguments(args);
displayFragment(fragNoConnection);
}
Then in ErrorFragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
TextView textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
//now retrieve the argument...
textTitle.setText(getArguments().getString("title"));
return rootView;
}
The Fragment will even remember it's arguments after an orientation change.
If you feel like being pedantic, you can create a static factory method within ErrorFragment that takes the title as an argument and then creates the Fragment and adds the argument, that way you can achieve proper encapsulation :)

You need to have a callback method in your ErrorFragment and when the view is inflated you then call the method in your callback interface in the onViewCreated and set the title.
sample:
in ErroFragment
public class ErroFragment extends Fragment
{
static interface ErrorDone{
public void doneInflating();
}
private TextView textTitle;
private ErrorDone ed;
public ErroFragment()
{
super();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
return rootView;
}
// Set methods
public void setTitle(int id) { textTitle.setText(id); }
public void setInterFace(ErrorDone er){ this.ed = er; }
}
Then you implement the interface in your AllQueuesFragment
public class AllQueuesFragment extends Fragment implements ErroFragment.ErrorDone
It will generate method doneInflating
and you need to set the interface:
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
fragNoConnection.setInterFace(this);
}
And in the generated method(doneInflating) of the AllQueuesFragment you then set the title in there:
public void doneInflating(){
fragNoConnection.setTitle(R.string.text_no_connection);
fragNoConnection.setIcon(R.drawable.thatfeel);
fragNoConnection.setLoaderVisibility(false);
}

If you want to be sure that the FragmentTransaction is commited and effective, you can use the executePendingTransactions method:
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
fragmentManager.executePendingTransactions();
But, the right way to do it is to send the title value to the Fragment when instantiating it. This is the default pattern when you create a Fragment from your IDE (eclipse or Android Studio)

Custom sliding menu

I've seen many post here, and one helped me, but I think I miss something...
I created an ActivitySlider with that (just a sample of code)
public ActivitySlider(FragmentActivity activity, String loginU, String passU, String phpsessid)
{
this.activity = activity;
bundle = new Bundle();
bundle.putString("loginU", loginU);
bundle.putString("passU", passU);
bundle.putString("phpsessid", phpsessid);
// We get the View of the Activity
this.content = (View) activity.findViewById(R.id.drawer_layout).getParent();
ListView listTmp = (ListView) content.findViewById(R.id.left_drawer);
String[] mMenuTitles = activity.getResources().getStringArray(R.array.menu_array);
String[] tmp = {"Hello","'Suuppppp"," ? "};
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this.activity, R.layout.drawer_list_item, tmp);
listTmp.setAdapter(adapter);
// And its parent
// The container for the menu Fragment is added to the parent. We set an id so we can perform FragmentTransactions later on
this.menuContainer = new FrameLayout(this.activity);
this.menuContainer.setId(R.id.content_frame);
// We set visibility to GONE because the menu is initially hidden
//this.menuContainer.setVisibility(View.GONE);
ViewGroup parent = (ViewGroup) this.content.getParent();
parent.addView(this.menuContainer);
}
public <T extends Fragment> void setMenuFragment(Class<T> cls)
{
Fragment fragment = Fragment.instantiate(this.activity, cls.getName());
setMenuFragment(fragment);
}
public void setMenuFragment(Fragment fragment)
{
FragmentManager manager = this.activity.getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
fragment.setArguments(bundle);
transaction.replace(R.id.content_frame, fragment);
transaction.commit();
}`
So, I call this Activity in another Activity (I can't use the navigation drawer with toggle because I already have tabs) :
slider = new ActivitySlider(this, loginU, passU, sessid);
slider.setMenuFragment(MenuFragment.class);
That's my MenuFragment code :
/**
* "Constructeur" : inflate la vue
*/
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
//Récupération des arguments
int i = getArguments().getInt(ARG_MENU_NUMBER);
String loginU = getArguments().getString("loginU");
String passU = getArguments().getString("passU");
String sessid = getArguments().getString("phpsessid");
Log.i("MenuFrag loginU + passU",loginU + " - " + passU);
Log.i("resArg", i + "");
String section = "";
View rootView = null;
switch(i)
{
//Home
case 0:
rootView = inflater.inflate(R.layout.home, container, false);
section = getResources().getStringArray(R.array.menu_array)[i];
getActivity().setTitle(section);
return rootView;
//Demandes/Propositions
case 1:
rootView = inflater.inflate(R.layout.activity_viewpagertabs, container, false);
section = getResources().getStringArray(R.array.menu_array)[i];
getActivity().setTitle(section);
Intent askpurp = new Intent(getActivity(),PagerWithTab.class);
Bundle bundle = new Bundle();
bundle.putString("loginU",loginU);
bundle.putString("passU",passU);
bundle.putString("phpsessid",sessid);
askpurp.putExtras(bundle);
getActivity().startActivity(askpurp);
return rootView;
//Awesome
case 2:
rootView = inflater.inflate(R.layout.awesome, container, false);
section = getResources().getStringArray(R.array.menu_array)[i];
getActivity().setTitle(section);
return rootView;
default:
rootView = inflater.inflate(R.layout.awesome2, container, false);
section = getResources().getStringArray(R.array.menu_array)[i];
getActivity().setTitle(section);
return rootView;
}
}
Sliding is working fine, but I've a white box on my left, and I expect my menu to be in there. What should I fix?

The MenuFragment class cannot be used like that. Here the new MenuFragment:
public class MenuFrag extends ListFragment
{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
return inflater.inflate(R.layout.menutest, null, false);
}
#Override
public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
String[] sections = getResources().getStringArray(R.array.menu_array);
ArrayAdapter<String> sectionAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, sections);
setListAdapter(sectionAdapter);
}
}
And here is the layout:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/android:list"
android:layout_alignParentRight="true"
android:background="#color/wezo_color_blue" android:layout_alignParentTop="true"/>
</RelativeLayout>
You can now call:
slider.setMenuFragment(MenuFrag.class);
The last problem to address is the menu size. All that needs to be done is to change the following line:
this.content = (View) activity.findViewById(R.id.drawer_layout).getParent();
to
this.content = (View) activity.findViewById(android.R.id.content).getParent();
If you don't do this, then it takes the actual content size (just after tabs).