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I want to pass data from an activity to a fragment, using an interface.
Please have a look at the code snippets below:
Interface:
public interface FragmentCommunicator {
public void passData(String name);
}
MainActivity:
public class MainActivity extends AppCompatActivity{
FragmentCommunicator fragmentCommunicator;
private Fragment fragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button) findViewById(R.id.button);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
fragment= new Fragment();
fragmentCommunicator = (FragmentCommunicator) getApplication();
fragmentCommunicator.passData("hello");
getSupportFragmentManager().beginTransaction().replace(R.id.container ,fragment).commit();
}
});
}
}
Fragment:
public class Fragment extends android.support.v4.app.Fragment implements FragmentCommunicator {
FragmentCommunicator communicator;
Context c;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment, null);
return view;
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.c = context;
}
#Override
public void passData(String name) {
Toast.makeText(c, name, Toast.LENGTH_SHORT).show();
}
}
I just want to pass some string when I click on button, (or some other event) to launch a fragment, and when the fragment is launched, it should show a toast containing that string...
Please help
any help would be appreciated.
Write this line of code after onCreate method.
public void passVal(FragmentCommunicator fragmentCommunicator) {
this.fragmentCommunicator = fragmentCommunicator;
}
Something like this
public class MainActivity extends AppCompatActivity{
FragmentCommunicator fragmentCommunicator;
private Fragment fragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button) findViewById(R.id.button);
fragment= new Fragment();
//App is crasing for this line. Working fine by removing it
//fragmentCommunicator = (FragmentCommunicator) getApplication();
//fragmentCommunicator.passData("hello");
getSupportFragmentManager().beginTransaction().replace(R.id.container ,fragment).commit();
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
fragmentCommunicator.passData("Hello");
}
});
}
//Here is new method
public void passVal(FragmentCommunicator fragmentCommunicator) {
this.fragmentCommunicator = fragmentCommunicator;
}
}
Then write this line of code into onCreateView() of your fragment. Something like this
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment, null);
((MainActivity) getActivity()).passVal(new FragmentCommunicator() {
#Override
public void passData(String name) {
Toast.makeText(c, name, Toast.LENGTH_SHORT).show();
}
});
return view;
}
Note: no need to implement FragmentCommunicator interface in your fragment. Hope it works. It works for me. I have tested
Activities contain fragments, you shouldn't need to pass anything. One technique would be to store your data in the activity scope and get a reference to it with getActivity().
Best practice to reference the parent activity of a fragment?
As far as the code you posted, I don't see where you call your pass data method within the fragment. I would suggest calling it in onviewcreated().
I will attempt to provide some sample code later as doing this on my mobile device is proving difficult.
Try passdata (getActivity ().someStringVariable);
In your Fragment class, have a TAG field. Naming a fragment Fragment can be a bit confusing as it is the same name as an Android Fragment, so I will use ExampleFragment:
public class ExampleFragment extends android.support.v4.app.Fragment implements FragmentCommunicator {
public static final String TAG = "ExampleFragment";
// ...
}
Now, when you replace the fragment in the activity, make sure to pass the TAG:
getSupportFragmentManager().beginTransaction().replace(R.id.container ,fragment, ExampleFragment.TAG).commit();
Note that in your case it would be Fragment.TAG, but I used ExampleFragment to clarify that Fragment.TAG is not part of the Android SDK.
To get a reference of your fragment in your activity, use the FragmentManager to find your fragment:
Fragment myFragment = getSupportFragmentManager().findFragmentByTag(ExampleFragment.TAG);
You can then make sure that myFragment is not null and cast it to FragmentCommunicator:
if (myFragment != null) {
fragmentCommunicator = (FragmentCommunicator) myFragment;
}
Note that in your example fragmentCommunicator = (FragmentCommunicator) getApplication(); is invalid because it is your fragment that is implementing the interface, not your application.
Related
I am having a fragment that contains for example one button, I want to allow the Activity containing the fragment to change this button view like for example color and title or src Image.
What's the best way to do that ?
Update : sorry If I wasn't clear enough but I want the activity to change the whole view as it's likes , like setting the padding, the color or anything.
It will create the view programmatically and the fragment should replace the old view by the new one and change the view's ID so that the fragment code isn't affected. And If i created methods in the fragment that takes these views when should the Main activity call them ? since the activity has to wait for the layout of the fragment to be created.
1. You must get you fragment from your activity
val fragment = supportFragmentManager.findFragmentByTag("tag")
or
val fragment = supportFragmentManager.findFragmentById(R.id.fragment)
2. Create a method that will do what you wants in you fragment and call this method from the activity
fragment.hideButton()
or you can use interface
Try this way according to your requirement
public abstract class BaseFragment extends Fragment {
BaseActivity yourActivity;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
yourActivity = (BaseActivity) context;
}
#Override
public void onDetach() {
yourActivity = null;
super.onDetach();
}
public void refreshview(){}
public void setDada(Data data){}
#override
publicn void onStart(){
yourActivity.setCurrentOpenedFragment(this);
}
}
Create the BaseActivity class
public abstract class BaseActivity extends AppCompatActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public void setCurrentOpenedFragment(BaseFragment currentFragment){}
}
Extends the BaseFragment in your fragment i.e.
public class YourFragment extends BaseFragment{
View view;
Button button;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment, container, false);
button = (Button)view.findViewById(R.id.button);
return view;
}
#override
publicn void onStart(){
super.onStart();
//yourActivity.setCurrentOpenedFragment(this);
}
Data data;
#override
public void setDada(Data data){
this.data = data;
}
#Override
public void refreshview() {
button.setcolor(data.getcolor());
}
}
Write the below line of code in your Activity class
public class YourActivity extends BaseActivity{
public static final byte NONE = -1;
public static final byte HOME = 1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_activity);
changeFragment(new YourFragment(), HOME);
initview();
}
public void initview(){
Button b = (Button)findViewById(R.id.button);
b.setOnClickListener(new OnClickListener(){
if(currentFragmentOnDrawer != null){
Data data = new Data();
data.setColor(getResource().getcolor(R.color.red));
currentFragmentOnDrawer.setDada(data);
currentFragmentOnDrawer.refreshview()
}
});
}
BaseFragment currentFragmentOnDrawer;
#Override
public void setCurrentOpenedFragment(BaseFragment currentFragment) {
super.setCurrentOpenedFragment(currentFragment);
this.currentFragmentOnDrawer = currentFragment;
}
public void changeFragment(Fragment targetFragment, byte state) {
FragmentTransaction ft = getSupportFragmentManager()
.beginTransaction();
ft.replace(R.id.main_fragment, targetFragment, "" + state);
ft.addToBackStack("" + state);
ft.commit();
}
}
Hope it will help for you
So basically, i have an activity called (Profile Activity) and two fragments connected to it (Profile view and profile edit fragment). Since im completely new with android studio, java language and fragments, im trying to place both fragments into activity but in a way that only profile view fragment is shown. Edit profile fragment needs to be hidden. Im using next part of the code:
getSupportFragmentManager().beginTransaction().add(R.id.profile_fragment, profileViewFragment).commit();
getSupportFragmentManager().beginTransaction().add(R.id.profile_fragment, profileEditFragment).commit();
I already tried something with "hide" and "show", but with no success. I have imported "android.support.v4.app.FragmentManager;" Thank you.
EDIT:
Profile activity after implementing new code:
public class ProfileActivity extends AppCompatActivity implements ProfileViewFragment.ProfileViewListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
//ovo ispod je za proslijedivanje iz activita u fragment
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
ProfileViewFragment profileViewFragment = new ProfileViewFragment();
ProfileEditFragment profileEditFragment=new ProfileEditFragment();
profileViewFragment.setArguments(getIntent().getExtras());
profileEditFragment.setArguments(getIntent().getExtras());
//getSupportFragmentManager().beginTransaction().add(R.id.profile_fragment, profileEditFragment).commit();
getSupportFragmentManager().beginTransaction().add(R.id.profile_fragment, profileViewFragment).commit();
//getSupportFragmentManager().beginTransaction().replace(R.id.profile_fragment, profileViewFragment).commit();
//FragmentManager fm=getSupportFragmentManager();
//fm.beginTransaction().setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out).show(new ProfileViewFragment()).commit();
//fm.beginTransaction().setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out).show(new ProfileEditFragment()).commit();
//-----------------------------------
}
#Override
public void onOpenProfileEditor() {
ProfileEditFragment profileEditFragment=new ProfileEditFragment();
profileEditFragment.setArguments(getIntent().getExtras());
getSupportFragmentManager().beginTransaction().replace(R.id.profile_fragment, profileEditFragment).commit();
}
#Override
public void onAttachFragment(Fragment fragment) {
if (fragment instanceof ProfileViewFragment) {
ProfileViewFragment profileFragment = (ProfileViewFragment) fragment;
profileFragment.setListener(this::onOpenProfileEditor);
}
}
}
Profile view fragment with new code:
public class ProfileViewFragment extends Fragment {
private Unbinder unbinder;
//novi kod sa stacka
private ProfileViewListener listener;
//-------------
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
FragmentProfileViewBinding viewBinding=DataBindingUtil.inflate(inflater, R.layout.fragment_profile_view, container, false);
View view=viewBinding.getRoot();
unbinder = ButterKnife.bind(this, view);
UserModel user = (UserModel) getArguments().get(ModelEnum.UserModel.name());
//viewBinding povezuje fragment i xml (proslijeduje user)
viewBinding.setUser(user);
//viewBinding.setUserGender(user);
return view;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
// #OnClick(R.id.btn_change_settings)
// public void changeSettings(){
//getActivity().getSupportFragmentManager().beginTransaction().replace(R.id.profile_fragment, new ProfileEditFragment()).commit();
// }
#Override
public void onDestroyView() {
super.onDestroyView();
unbinder.unbind();
}
//ISPOD JE NOVI KOD SA STACK OVERFLOWA
public interface ProfileViewListener{
void onProfileEditor();
}
public void setListener(ProfileViewListener listener) {
this.listener = listener;
}
#OnClick(R.id.btn_change_settings)
public void onEdit(View view){
if(listener!=null){
onOpenProfileEditor();
}
}
}
Instead of
getSupportFragmentManager().beginTransaction().add(R.id.profile_fragment, profileEditFragment).commit();
It must be
getSupportFragmentManager().beginTransaction().replace(R.id.profile_fragment, profileEditFragment).commit();
This will replace your fragment, instead of adding it.
Please, also note that you must call "add" for the first time and use "replace" afterwards.
You may find more about fragments here: https://developer.android.com/training/basics/fragments/fragment-ui
EDIT
For the new issue you have outlined, the solution is to "report" you activity that an event had happened, so it can take action. Here is how to do that.
First, we need an interface (you can add it inside you Profile fragment) and to link the activity to our fragment, if it implements that interface.
public class ProfileViewFragment extends Fragment {
...
...
private ProfileViewListener listener;
...
...
#OnClick(R.id.btn_change_settings)
public onEdit(View view) {
// If there is anyone listening, report that we need to open editor
if (listener != null) {
listener .onOpenProfileEditor();
}
}
public void setListener(ProfileViewListener listener) {
this.listener = listener;
}
// The interface
public interface ProfileViewListener {
void onOpenProfileEditor();
}
}
And in the class, we need to implement the interface and subscribe as a listener.
public class ProfileActivity extends AppCompatActivity implements ProfileViewFragment.ProfileViewListener {
...
...
#Override
public void onOpenProfileEditor() {
ProfileEditFragment profileEditFragment=new ProfileEditFragment();
profileEditFragment.setArguments(getIntent().getExtras());
getSupportFragmentManager()
.beginTransaction
.replace(R.id.profile_fragment, profileEditFragment)
.commit();
}
#Override
public void onAttachFragment(Fragment fragment) {
if (fragment instanceof ProfileViewFragment) {
ProfileViewFragment profileFragment = (ProfileViewFragment) fragment;
profileFragment.setListener(this);
}
}
}
You may find more detail on Activity-Fragment communication here - https://developer.android.com/training/basics/fragments/communicating
I'm going from a Fragment -> Activity. In the activity I make an interface and when the user clicks a button I pass in a string to an interface object I create and call finish(). In the fragment I implement that interface and want to get that string. But in the activity I get a crash saying the listener is null.
public class SampleActivity extends AppCompatActivity
{
private Button button;
private MatchActivity.OnMatchCompleteListener onMatchCompleteListener;
public interface OnMatchCompleteListener
{
public void matchComplete(String matchID);
}
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.someButton);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onMatchCompleteListener.matchComplete("finished");
finish();
}
});
}
}
Fragment
public class SampleFragment extends Fragment implements SampleActivity.OnMatchCompleteListener{
private View rootView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_login , container, false);
return rootView;
}
#Override
public void matchComplete(String matchID) {
Log.d("TEST",matchID);
}
}
if you have your fragment in the R.layout.activity_main and your fragment id is R.id.fragment use this:
onMatchCompleteListener =
((SampleFragment)getFragmentManager().findFragmentById(R.id.fragment))
otherwise use this solution:
SampleFragment fragment = new SampleFragment();
onMatchCompleteListener = fragment;
getFragmentManager().beginTransaction().add(R.layout.activity_main, fragment, "TAG_SIMPLE").commit();
im a new guy on this programming world so i guess this question is simple. So I have one imagebutton on my fragment and I whatI want is that when I click on it, it does a fragment transaction to another fragment; but the thing is that when I run the app and click on the imagebutton, it only "superimposes" the content of the other fragment into the one where the imagebutton is, of course what i want to do is just to go to the other fragment, ive been dealing with this for a while so I hope someone helps me, thanks.
Here is my java code of the fragment
public class inicio extends Fragment {
public inicio() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.fragment_inicio,container,false);
ImageButton luces = (ImageButton)view.findViewById(R.id.imageButton);
luces.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
interior interior= new interior();
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.inicioo, interior).commit();
}
});
}
}
New code added...
public class transaction extends MainActivity
implements com.example.administradora.prueba.inicio.OnSelectedListener{
public void onButtonSelected() {
interior interior= new interior();
getSupportFragmentManager().beginTransaction().replace(R.id.inicioo, interior).commit();
}
}
but i get this error in the logcat:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.administradora.prueba/com.example.administradora.prueba.MainActivity}: java.lang.ClassCastException: com.example.administradora.prueba.MainActivity#20f8fe9b must implement OnSelectedListener
You shouldn't replace a Fragment from another Fragment. Try to do that through the Activity.
Define some interface for the Fragment to hold
public class MyFragment extends Fragment {
OnSelectedListener mCallback;
// Container Activity must implement this interface
public interface OnSelectedListener {
public void onButtonSelected();
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
mCallback = (OnSelectedListener ) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnSelectedListener");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.fragment_inicio,container,false);
ImageButton luces = (ImageButton)view.findViewById(R.id.imageButton);
luces.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Send the event to the host activity
if (mCallback != null) mCallback.onButtonSelected();
}
});
return view;
}
}
And swap the Fragment container in the interface implementation from the Activity.
public class MainActivity extends Activity
implements MyFragment.OnSelectedListener{
...
public void onButtonSelected() {
interior interior= new interior();
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.inicioo, interior)
.commit();
}
}
The first two sections of Communicating with Other Fragments is what you are looking for.
I have an Activity that starts a Fragment. Inside that fragment i have an EditText. And when i get the text that the user types there, i want to get that from my Activity with the help of an interface. I'm using this guide
On my MainActivity i'm implementing the commentListener interface and i've managed to get the result inside the onCommentEntered method. But on doneListener, which is triggered when the user presses a button finishing the activity, i'm getting null.
Obviously onCommentEntered runs after doneListener.
Any suggestions on how to get the result on doneListener?
class MainActivity implements fragment.commentListener{
static String comment;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addtransaction);
done=(TextView)findViewById(R.id.done_button);
}
// called when user presses a button and MainActivity finishes.
public void doneListener(View v){
// Here i get NULL
System.out.println(comment);
finish();
}
#Override
public void onCommentEntered(String data) {
comment=data;
// Here i get what the user typed
System.out.println(comment);
}
}
My fragment
public class thefragment extends Fragment {
commentListener cListener;
static TextView note;
EditText comment;
public interface commentListener{
void onCommentEntered(String data);
}
public static thefragment newInstance(){
return new thefragment ();
}
public thefragment (){
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
cListener=(commentListener) context;
}
#Override
public void onDetach() {
super.onDetach();
cListener=null;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v;
v=inflater.inflate(R.layout.fragment, container, false);
comment=(EditText)v.findViewById(R.id.comment_picker);
comment.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
cListener.onCommentEntered(comment.getText().toString());
}
}
});
return v;
}
}
Create a new Interface, as well as implement the same in Fragment. create a method in the interface and override the same in Fragments. While calling the fragment from Activity create an Interface type fragment and call the interface method.
eg:
public class thefragment extends Fragment implement fragmentNofyInterface {
...
#Override
protected void notify(String txt){
mTvTxt.setText(txt);
}
.....
}
Interface Format
public interface fragmentNofyInterface {
protected void notify(String txt);
}
Activity format
class MainActivity implements fragment.commentListener{
.....
private fragmentNofyInterface mFragmentNotifier;
.........
thefragment mFragment = new thefragment();
mFragmentNotifier = (fragmentNofyInterface ) mFragment;
FragmentTransaction transaction = mFragmentMngr.beginTransaction().
add(R.id.rl_fragment_navigation_container,
mFragment);
transaction .commit();
......
//Notify the fragment when you required
mFragmentNotifier.notify("hello world");
}
Switching to addTextChangedListener and TextWatcher for my EditText, like this here,
seems to fix my problem.Now onCommentEntered method is called before doneListener and thus String commentgets whatever was typed in the EditText.Thanks everyone for helping.