I have an app which has one MainActivity and two Fragments. These fragments send argument to MainActivity this way:
Bundle args = new Bundle();
args.putLong("id",id);
sf.setArguments(args);
And then MainActivity takes argument in onCreate() method
protected void onCreate(Bundle savedInstanceState) {
private long wayId = getArguments().getLong("id");
}
How can I determine which fragment sent this argument to MainActivity ?
You can add another argument into the bundle like the tag of the fragment.
Bundle args = new Bundle();
args.putLong("id",id);
args.putString("fragmentTag", fragmentTag);
sf.setArguments(args);
and retrive the tag in your onCreate()
You can define a separate inrterface for every fragment
public class FragmentA extends Fragment {
public static interface FragmentAInterface {
void doSomething(String data);
}
}
public class FragmentB extends Fragment {
public static interface FragmentBInterface {
void doSomething(String data);
}
}
And then in your activity:
public class MyActivity extends AppCompatActivity implements FragmentA.FragmentAInterface, FragmentB.FragmentBInterface{
#Override
public void doSomething(String data) {
//Guaranteed to come from Fragment A
}
#Override
public void doOtherThing(String data) {
//Guaranteed to come from Fragment B
}
}
Related
I find it very difficult to call the InsertSlider in the MainFragment from the BottomSheetDialog.
Any help and thanks
In the BottomSheet :
public class AdminBottomSheetMainSave extends BottomSheetDialogFragment
{
// One Method I don.t Know How To Work
//((MainFragment)getContext()).InsertSliders(new ImageSlider(0,Name,Image,Price,Description));
// Not Work Too
MainFragment fragment = new MainFragment();
fragment.InsertSliders(new ImageSlider(0,Name,Image,Price,Description));
}
In the Fragment :
public class MainFragment extends Fragment
{
public void InsertSliders(ImageSlider imageSlider)
{
imageSliderViewModel.insert(imageSlider);
Toast.makeText(getActivity(), "Done Insert"+imageSlider, Toast.LENGTH_SHORT).show();
}
What is the contact method how do I get to InsertSliders
you should use interface to communicate between two fragments and you need an activity to implement the interface.
define interface in your bottomsheetdialogfragment:
public class AdminBottomSheetMainSave extends BottomSheetDialogFragment
{
public Callback mCallback;
public interface Callback{
void insertSlider(ImageSlider slider);
}
#Override
public void onAttach(Activity activity){
super.onAttach(activity);
mCallback = (Callback) activity;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//...
mCallback.insertSlider(new ImageSlider(0,Name,Image,Price,Description));
}
}
then in your activity in our case MainActivity implement Callback interface and override inserSlider method:
public class MainActivity extends AppCompatActivity implements Callback{
MainFragment mainFragment;
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//...
if(savedInstanceState == null){
mainFragment = MainFragment.newInstance(new Bundle()); // use real bundle here
getSupportFragmentManager()
.beginTransaction()
.add(R.id.fragment_holder, mainFragment, "FragMain").commit();
}
}
// Interface method
#Override
public void insertSlider(ImageSlider slider){
if(mainFragment != null){
mainFragment.insertSlider(slider);
}
}
now in your MainFragment:
public class MainFragment extends Fragment{
public static MainFragment newInstance(Bundle args){
MainFragment fragment = new MainFragment();
fragment.setArguments(args);
return fragment;
}
//... Class overrides here onCreateView etc..
// define insertSlider method
public void insertSlider(ImageSlider slider){
imageSliderViewModel.insert(slider);
Toast.makeText(getActivity(), "Done Insert"+slider, Toast.LENGTH_SHORT).show();
}
I have not found a clear solution anywhere on stack for this.
Here's my basic set up
public class Activity1 extends AppCompatActivity
{
private OnAttributesUpdatedListener onAttributesUpdatedListener;
public interface OnAttributesUpdatedListener
{
public void onAttributesUpdated();
}
public void setTargetFragment(Fragment fragment)
{
this.onAttributesUpdatedListener = (OnAttributesUpdatedListener) fragment;
}
private void whenFinishedSomethingCallback()
{
onAttributesUpdatedListener.onAttributesUpdated();
}
}
public class Fragment1 extends Fragment implements Activity1.OnAttributesUpdatedListener
{
button.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view) {
if(rivalButtonClick == 0)
{
Activity1 activity1 = new Activity1();
activity1.setTargetFragment(Fragment1.this);
startActivity(new Intent(getActivity(), activity1.getClass()));
}
}
});
}
I get a null pointer exception and crashes on : onAttributesUpdatedListener.onAttributesUpdated(); because for some reason my listener never gets set properly. What's the proper way to do this?
You need to set the listener at start of the fragment onCreatView() or in onActivityCreated() only if the Desired Activity is a parent Activity of that particular fragment. Below is an example .
public class Activity1 extends AppCompatActivity {
private OnAttributesUpdatedListener onAttributesUpdatedListener;
public interface OnAttributesUpdatedListener {
public void onAttributesUpdated();
}
public void setListener(OnAttributesUpdatedListener onAttributesUpdatedListener) {
this.onAttributesUpdatedListener = onAttributesUpdatedListener;
}
private void whenFinishedSomethingCallback() {
if(onAttributesUpdatedListener!=null)
onAttributesUpdatedListener.onAttributesUpdated();
}
}
public class Fragment1 extends Fragment implements Activity1.OnAttributesUpdatedListener
{
#Override
public void onAttributesUpdated() {
// Do your stuff here
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
((Activity1)getActivity()).setListener(this);
}
}
Read about fragment Life cycle to make use of getActivity(). also remove the listener when fragment is destroyed .
Use LocalBroadcastManager for communicating between in case the Fragment exists in other Activity.
At first create an Interface like this:
public interface Listener{
void doSomething() }
Then implement this interface in your activity.
And also add
Listener listener
In your fragment
And in onAttach method in fragment use this
listener=(Listener)activity
Then call listener whenever you need .
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.
i'm trying to send data from activity to fragment
here is the activity code :
Bundle args=new Bundle();
args.putString("username", username);
ViewEmpAttend fragobj=new ViewEmpAttend();
fragobj.setArguments(args);
here is the fragment code :
username=this.getArguments().getString("username");
but this code gives me an error said "null object reference" in the onCreateView method in (Fragment Class) .
please help :)
Try to retrieve arguments from onCreate of Fragment
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String username = this.getArguments().getString("username");
}
In activity define one method.
public class MainActivity extends AppCompatActivity {
String name;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//your code
}
//define this method
public String getName(){
this.name = username;
}}
In fragment use following code.
String userName = ((activityName) getActivity()).getName();//you will get name here.
For something simple like that, i will just create a constructor method in the fragment to pass in a string.
for example
public class MyFragment extends Fragment{
private String myString;
public MyFragment (){
// Recommended Empty Constructor
}
public MyFragment (String yourString){
this.myString = yourString;
}
}
On your Activity class you can pass in the string direct to your fragment constructor
public MyClass extends Activity{
#override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
openFragment();
}
public void openFragment(){
MyFragment fragment = new Fragment("yourString");
// Here begin the fragment transaction
}
}
I have a main activity class, and a private inner class within the main activity. The private inner class has methods that when called will display fragments. This inner class implements an interface defined in the Fragment's class, to be used as a sort of callback. It is probably easiest to show through code.
public class MainActivity extends FragmentActivity {
//on a button clicked
EditItemManger em = new EditItemManager();
em.begin();
private class EditItemManager implements on EditItemFragment.EditedItemClickedListener{
//consructor, other stuff. no onCreate method because this inner class does not (explicity??) extend activty
public void begin(){
EditItemFragment editItemFrag = new EditItemFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.add(editItemFrag, EDIT_FRAG_TAG)
fragmentTransaction.commit();
}
#Override
public void onEditItemClicked() {
editFinish();
}
public void editFinish()
{
// other stuff
}
}
}
My EditItemFragment class, where the onAttach method always has a null activity parameter
public class EditItemFragment extends DialogFragment {
protected EditedItemClickedListener editedItemClickedListener;
protected ImageButton button;
public EditItemFragment(){}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
final Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.edit_name_fragment, container, false);
button = (ImageButton) view.findViewById(R.id.submit_new_item_button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
editedItemClickedListener.onEditedItemButtonClicked();
}
});
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
editedItemClickedListener= (EditedItemClickedListener) activity;
} catch (ClassCastException e) {
e.printStackTrace();
}
}
public interface OnEditNameButtonClickedListener {
public void onEditNameButtonClicked();
}
So because the parameter in onAttach() in my Fragment class is always null, it eventually causes a null pointer exception. I am wondering if it is because the fragment is called from a class that is not extending activity. The problem is that if this class extends activity, there will be an issue with trying to commit the Fragment Transaction
I guest your onAttach returns nullpointer exception. Its because your parent Activity the main activity doesnt implement your custom interface so it return null. See the code below let me know if it help you:
public class MainActivity extends FragmentActivity implements EditItemFragment.EditedItemClickedListener{
private DialogFragment editItemDialog;
//Do your code here
#Override
public void onEditItemClicked() {
editFinish();
}
public void showDialog(){
//this is for showing your custom dialog fragment
editItemDialog = EditItemFragment.newInstance();
editItemDialog.show(getSupportFragmentManager(),"editItemDialog");
}
}
this is for your EditItemFragment:
public class EditItemFragment extends DialogFragment{
//Do your code here
public static EditItemFragment newInstance(){
EditItemFragment editItemDialog = new EditItemFragment();
return editItemDialog;
}
}