Fragments should comunicate through an activity so i will post you a short example of how to correctly send data from one fragment to another using a host activity:
First we will use this layout named host activity layout with a framelayout as a parent called host_fragment_container :
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/host_fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
now we are going to load our host activity and set this layout as a content view and create a basic method to change fragments on this frame layout :
public class HostActivity extends AppCompatActivity
implements TextViewContainerFragment.textViewClickListener{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.host_activity_layout);
}
private void switchFragment(Fragment fragment) {
getSupportFragmentManager().beginTransaction()
.replace(R.id.host_fragment_container, fragment)
.commit();
}
}
Now lets create our first fragment (the one who will send the text) :
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:id="@+id/text_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
we will use this same xml file for both sender and receiver fragments
public class TextViewContainerFragment extends Fragment {
public interface textViewClickListener {
void onTextViewClicked(String value);
}
private textViewClickListener mActivityCallback;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.text_view_container_fragment, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
final TextView textView = (TextView) view.findViewById(R.id.text_view);
//search the view by id and cast it into a text view the set it on click lsitener
textView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// now if the cast was successful the activity callback will be valid and ready to use
// but we are going to check if its valid anyways
if (mActivityCallback != null) {
mActivityCallback.onTextViewClicked(textView.getText().toString());
}
}
});
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
// if context is extracted from an activity
// that means its safe to cast
if (context instanceof Activity) {
mActivityCallback =
(textViewClickListener) context;
}
}
// factory method
public static TextViewContainerFragment newInstance() {
return new TextViewContainerFragment();
}
}
now that we have our interface on the fragment we will implement it on the host activity to listen for callbacks & its going to call a sencond fragment ot display the sent text :
public class HostActivity extends AppCompatActivity
implements TextViewContainerFragment.textViewClickListener{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.host_activity_layout);
if (savedInstanceState == null) {
switchFragment(TextViewContainerFragment.newInstance());
}
}
private void switchFragment(Fragment fragment) {
getSupportFragmentManager().beginTransaction()
.replace(R.id.host_fragment_container, fragment)
.commit();
}
@Override
public void onTextViewClicked(String value) {
switchFragment(TextReceiverFragment.newInstance(value));
}
}
Here is the code for the receiver fragment (older fragment will be replaced for this one) :
public class TextReceiverFragment extends Fragment {
public static final String ARG_TEXT_RECEIVED_FROM_ANOTHER_FRAGMENT = "text";
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.text_view_container_fragment, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
((TextView) view.findViewById(R.id.text_view)).setText(getArguments() != null ?
getArguments().getString(ARG_TEXT_RECEIVED_FROM_ANOTHER_FRAGMENT)
: "No text was sent from another fragment");
}
public static TextReceiverFragment newInstance(String text) {
TextReceiverFragment fragment = new TextReceiverFragment();
Bundle argument = new Bundle();
argument.putString(ARG_TEXT_RECEIVED_FROM_ANOTHER_FRAGMENT,
text);
fragment.setArguments(argument);
return fragment;
}
}
