I was trying to migrate from ButterKnife to Android data binding.
When using ButterKnife (which is working perfectly fine):
// Called after a network call
public void updateView(MyAdapter adapter, String title) {
toolbar.setTitle(title);
recyclerView.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(adapter);
}
Using Android data binding:
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
binding = MyFragmentBinding.inflate(inflater, container, false);
binding.toolbar.setTitle(R.string.app_name); // this works
return binding.getRoot();
}
// Called after a network call
public void updateView(MyAdapter adapter, String title) {
binding.toolbar.setTitle(title);
binding.recyclerView.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
binding.recyclerView.setLayoutManager(layoutManager);
binding.recyclerView.setAdapter(adapter);
}
After calling updateView on the later code, the screen goes blank.
I debugged to find out that view remains attached to the Fragment.
Also, if I am updating something inside onCreateView then that works.
Is there anything am I doing wrong?
Layout:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:layout_alignParentTop="true"
android:background="?attr/colorPrimary"
android:elevation="#dimen/_6sdp"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:navigationIcon="#drawable/default_nav_icon_back"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="?attr/actionBarSize" />
</android.support.design.widget.CoordinatorLayout>
</layout>
Related
I'm trying to implement RecyclerView in my android app but it gives me error
"RecyclerView has no Layoutmanager"
even though I initialize it in my code. My java and xml file:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.activity_list, container, false);
mRecyclerView = rootView.findViewById(R.id.recyclerView);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
mRecyclerView.setLayoutManager(layoutManager);
mAdapter = new CustomAdapter(mDataset);
mRecyclerView.setAdapter(mAdapter);
return rootView;
}
XML
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".List"
android:background="#color/black">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="495dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="parent"/
</androidx.constraintlayout.widget.ConstraintLayout>
You can't use signal activity for recy.... And main activity . Plz create a new xml file like list_file
Are you sure that added recyclerview dependency into gradle
AndroidX
implementation 'androidx.recyclerview:recyclerview:1.1.0'
Support library
implementation 'com.android.support:recyclerview-v7:28.0.0'
How to handle empty data View in a RecyclerView ,I have tried so many ways from internet but none seems to work. I am also using realm database so I don't know if this is the right way to check if it is empty or not.
this is my Fragment xml where the RecyclerView is located
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/tv_no_data"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/holo_green_dark"
android:gravity="center"
android:text="emptty"
android:textAppearance="?android:textAppearanceMedium"
android:textColor="#android:color/white"
android:visibility="invisible" />
<android.support.v7.widget.RecyclerView
android:id="#+id/rv_favorite"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimaryDark">
</android.support.v7.widget.RecyclerView>
</FrameLayout>
and this is my fragment class
public class FavouriteFragment extends Fragment {
RecyclerView mRecyclerView;
FavouriteAdapter adapter;
Realm mRealm;
int positions;
TextView emptyText;
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.favourite_fragment,container,false);
mRealm=Realm.getDefaultInstance();
RealmQuery<news> quotesRealmQuery = mRealm.where(News.class).equalTo("favourite",true);
RealmResults<News> mResults = newsRealmQuery.findAll();
emptyText= (TextView) view.findViewById(R.id.tv_no_data);
//adapter=new FavouriteAdapter(getActivity(),mResults,mRealm);
mRecyclerView= (RecyclerView) view.findViewById(R.id.rv_favorite);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
if (!mResults.isEmpty()) {
//if data is available, don't show the empty text
emptyText.setVisibility(View.INVISIBLE);
adapter=new FavouriteAdapter(getActivity(),mResults,mRealm,pos,single);
mRecyclerView.setAdapter(adapter);
mRealm.addChangeListener(new RealmChangeListener<Realm>() {
#Override
public void onChange(Realm element) {
adapter.notifyItemRemoved(positions);
}
});
} else
emptyText.setVisibility(View.VISIBLE);
return view;
}
Your RecyclerView is not transparent so you should remember to hide it when is empty:
if (!mResults.isEmpty()) {
//if data is available, don't show the empty text
emptyText.setVisibility(View.INVISIBLE);
mRecyclerView.setVisibility(View.VISIBLE);
} else {
emptyText.setVisibility(View.VISIBLE);
mRecyclerView.setVisibility(View.GONE);
}
I am trying to have multiple RecyclerViews in a layout but I get the following error: "LayoutManager is already attached to a RecyclerView"
The Java code is:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_squad, container, false);
Activity parentActivity = getActivity();
final ObservableScrollView scrollView = (ObservableScrollView) view.findViewById(R.id.squad_scrollview);
final RecyclerView gkRecyclerView = (RecyclerView) view.findViewById(R.id.gk_recycler);
final RecyclerView coachRecyclerView = (RecyclerView) view.findViewById(R.id.coach_recycler);
coachRecyclerView.setAdapter(new SquadRecyclerAdapter(parentActivity, getSquadDummyData(0)));
coachRecyclerView.setLayoutManager(new MyLinearLayoutManager(parentActivity, LinearLayoutManager.VERTICAL, false));
coachRecyclerView.setHasFixedSize(false);
gkRecyclerView.setAdapter(new SquadRecyclerAdapter(parentActivity, getSquadDummyData(1)));
gkRecyclerView.setLayoutManager(new MyLinearLayoutManager(parentActivity, LinearLayoutManager.VERTICAL, false));
gkRecyclerView.setHasFixedSize(false);
scrollView.setTouchInterceptionViewGroup((ViewGroup) parentActivity.findViewById(R.id.container));
if (parentActivity instanceof ObservableScrollViewCallbacks) {
scrollView.setScrollViewCallbacks((ObservableScrollViewCallbacks) parentActivity);
}
return view;
}
The XML layout code is:
<com.github.ksoichiro.android.observablescrollview.ObservableScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/squad_scrollview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="#dimen/margin_medium"
>
<LinearLayout
android:id="#+id/squad_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/seasons_scrollview"
android:divider="#drawable/nav_bar_divider"
android:elevation="#dimen/card_elevation"
android:orientation="vertical"
android:showDividers="middle">
<LinearLayout
android:id="#+id/coach_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="#dimen/margin_small"
android:paddingLeft="#dimen/margin_standard"
android:paddingRight="#dimen/margin_standard"
android:paddingTop="#dimen/margin_small">
<TextView
android:id="#+id/squad_coach_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Coach"
android:textSize="#dimen/text_size_standard" />
<android.support.v7.widget.RecyclerView
android:id="#+id/coach_recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/margin_small"
android:paddingBottom="#dimen/margin_small"
android:scrollbars="none">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
<LinearLayout
android:id="#+id/gk_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="#dimen/margin_small"
android:paddingLeft="#dimen/margin_standard"
android:paddingRight="#dimen/margin_standard"
android:paddingTop="#dimen/margin_small">
<TextView
android:id="#+id/squad_gk_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Goalkeepers"
android:textSize="#dimen/text_size_standard" />
<android.support.v7.widget.RecyclerView
android:id="#+id/gk_recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/margin_small"
android:paddingBottom="#dimen/margin_small"
android:scrollbars="none">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
<LinearLayout
android:id="#+id/def_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="#dimen/margin_small"
android:paddingLeft="#dimen/margin_standard"
android:paddingRight="#dimen/margin_standard"
android:paddingTop="#dimen/margin_small">
<TextView
android:id="#+id/squad_def_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Defense"
android:textSize="#dimen/text_size_standard" />
</LinearLayout>
<LinearLayout
android:id="#+id/mid_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="#dimen/margin_small"
android:paddingLeft="#dimen/margin_standard"
android:paddingRight="#dimen/margin_standard"
android:paddingTop="#dimen/margin_small">
<TextView
android:id="#+id/squad_mid_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Midfielders"
android:textSize="#dimen/text_size_standard" />
</LinearLayout>
<LinearLayout
android:id="#+id/for_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="#dimen/margin_small"
android:paddingLeft="#dimen/margin_standard"
android:paddingRight="#dimen/margin_standard"
android:paddingTop="#dimen/margin_small">
<TextView
android:id="#+id/squad_for_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Forwards"
android:textSize="#dimen/text_size_standard" />
</LinearLayout>
</LinearLayout>
</com.github.ksoichiro.android.observablescrollview.ObservableScrollView>
The MyLinearLayoutManager is a custom LinearLayoutManager I found online in order to solve the wrap-content issue of the SDK LinearLayoutManager.
Is there any way I can have multiple RecyclerViews in a single layout? It seems that I cannot attach more than one LayoutManagers per layout.
Any assistance would be very welcome :)
I had this problem too. My Activity uses Tabs, with three fragments, when I go to third tab, and back to first (or second), this error is thrown.
After searching a lot, I found out that may be the garbage collector, because I was using a strong reference.
Since the constructor LinearLayoutManager uses the activity as the parameter (not the fragment), a Tabs Activity stays active during tabs changes.
Removing the local field in mLinearLayoutManager from the class, and using a weak reference, I could get rid of this problem:
before:
public class MyFragment1 extends Fragment
private LinearLayoutManager linearLayoutManager;
#Override
public void onCreate(Bundle savedInstanceState) {
linearLayoutManager = new LinearLayoutManager(getActivity());
(...)
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
(...)
mRecyclerView.setLayoutManager(linearLayoutManager);
}
}
I changed to:
public class MyFragment1 extends Fragment {
// private LinearLayoutManager linearLayoutManager;
#Override
public void onCreate(Bundle savedInstanceState) {
// linearLayoutManager = new LinearLayoutManager(getActivity());
(...)
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
(...)
mRecyclerView.setLayoutManager(
new LinearLayoutManager(getActivity()));
}
}
Just need to create a new instance:
RecyclerView recyclerView = new RecyclerView(getContext());
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()))
I faced this error when providing LayoutManager via Dagger. The solution is to replace layout manager injection with layout manager javax.inject.Provider injection.
#Inject
lateinit var layoutManager: Provider<RecyclerView.LayoutManager>
...
recyclerView.setLayoutManager(layoutManager.get())
I have the same problem as well. I work around it by setting null to LinearLayoutManager instance.
public class MyFragment extends Fragment {
protected LinearLayoutManager mLinearLayoutManager;
...
#Override
public void onDestroy() {
super.onDestroy();
if(mLinearLayoutManager != null) // Workaround: android.support.v7.widget.LinearLayoutManager is already attached to a RecyclerView
mLinearLayoutManager = null;
}
I opened FragmentB from FragmentA. Then returned back to FragmentA and got this exception. I found an error. I created in onCreate:
linearLayoutManager = LinearLayoutManager(requireContext())
and used in it onCreateView:
view.recycler_view.layoutManager = linearLayoutManager
Because linearLayoutManager hadn't recreated when we returned from FragmentB, RecyclerView used an old linearLayoutManager. So, I moved linearLayoutManager = LinearLayoutManager(requireContext()) to onCreateView.
In my case, I had declared a LinearLayoutManager globally and I was trying to attach the same instance of LinearLayoutManager to multiple RecyclerView's so I was getting this error.
The Solution is to attach different LayoutManager to each RecyclerView because one LayoutManager can only be attached to one Recyclerview.
I had this problem with Dagger2 and it was solved by removing the Scope Annotation.
I had annotated the code with some scope and when i removed the scope the problem was fixed.
I hope this would be helpful to you.
#MyScope #Provides static LinearLayoutManager provideLinearLayoutManager
I deleted the #MyScope.
This error I faced with Daggar2
and simply remove by using Provider before the LinearLayoutManager like;
#Inject
Provider <LinearLayoutManager> linearLayoutManager;
mViewDataBinding.rvResult.setLayoutManager(linearLayoutManager.get());
Possible options to fix this crash:
Create an instance of LayoutManager in onViewCreated of Fragment:
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
recyclerView.layoutManager = LinearLayoutManager(context)
}
If it is necessary to have an instance of LayoutManager as a variable in Fragment, then detach the instance from RecyclerView in onDestroyView:
class MyFragment : Fragment() {
private val myLayoutManager by lazy { LinearLayoutManager(context) }
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
recyclerView.layoutManager = myLayoutManager
}
override fun onDestroyView() {
recyclerView.layoutManager = null
super.onDestroyView()
}
}
The second option will work, because the condition for throwing an exception will be false. Here is the code from the method setLayoutManager of RecyclerView:
...
if (layout != null) {
if (layout.mRecyclerView != null) { // will be false
throw new IllegalArgumentException("LayoutManager " + layout
+ " is already attached to a RecyclerView:"
+ layout.mRecyclerView.exceptionLabel());
}
mLayout.setRecyclerView(this);
if (mIsAttached) {
mLayout.dispatchAttachedToWindow(this);
}
}
I recently started using RecyclerView replacing older ListView. But whenever I use android:scrollbars="vertical" in android.support.v7.widget.RecyclerView element, my app crashes with the following error:
Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$LayoutManager.canScrollVertically()' on a null object reference
This is how I'm using RecyclerView:
View rootView;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.my_fragment, container, false);
return rootView;
}
protected void onPostExecute(Boolean result) {
RecyclerView rv = (RecyclerView) rootView.findViewById(R.id.recyclerview);
LinearLayoutManager llm = new LinearLayoutManager(context);
rv.setLayoutManager(llm);
RecycleViewAdapter adapter = new RecycleViewAdapter(myRecyclerViewAdapter);
rv.setHasFixedSize(true);
rv.setAdapter(adapter);
}
And this is my_fragment.xml file:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
Everything works perfectly fine if I don't use android:scrollbars="vertical". Thanks for your help.
When using the RecyclerView you don't really need to specify the scrollbars display; it is the LayoutManager job where you specify if it is Vertical or Horizontal orientation and of course the scrollbar display will automatically change whatever orientation you choose.
//for vertical scrollbar and orientation
LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false);
//for horizontal scrollbar and orientation
LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false);
I'm trying to adapt the strategy for hiding / showing a toolbar (or any visual element) from the well explained and great article:
http://mzgreen.github.io/2015/02/15/How-to-hideshow-Toolbar-when-list-is-scroling%28part1%29/
But in my case I'm using a Fragment to hold the recycleview instead of the activity. My problem is that the padding is not being applied so the first element is under the toolbar, and I have also another strange behavior, as the toolbar is also under the statusbar. I don't know what is happening here.
The following are my "moving pieces":
BasicActivity.java: based on the one given on the previous post, but moving away the recycleview part as is going to be on the Fragment piece. Also it exposes the show and hide methods to allow the fragment to access it:
public class BasicActivity extends ActionBarActivity {
private Toolbar mToolbar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_basic);
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container,new RecycleFragment())
.commit();
overridePendingTransition(0, 0);
initToolbar();
}
private void initToolbar() {
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
setTitle(getString(R.string.app_name));
mToolbar.setTitleTextColor(getResources().getColor(android.R.color.white));
}
public void hideViews() {
mToolbar.animate().translationY(-mToolbar.getHeight()).setInterpolator(new AccelerateInterpolator(2));
}
public void showViews() {
mToolbar.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2));
}
}
My activiy_basic.xml is the following:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<include layout="#layout/toolbar_actionbar" />
</FrameLayout>
The layout toolbar_actionbar.xml
<android.support.v7.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:clipToPadding="false"/>
The Fragment RecycleFragment.java:
public class RecycleFragment extends Fragment {
#Override public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_recycler, container, false);
return view;
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
initRecyclerView(view);
}
private void initRecyclerView(View view) {
RecyclerView recyclerView = (RecyclerView)view.findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
RecyclerAdapter recyclerAdapter = new RecyclerAdapter(createItemList());
recyclerView.setAdapter(recyclerAdapter);
recyclerView.setOnScrollListener(new HidingScrollListener() {
#Override
public void onHide() {
((BasicActivity)getActivity()).hideViews();
}
#Override
public void onShow() {
((BasicActivity)getActivity()).showViews();
}
});
}
private List<String> createItemList() {
List<String> itemList = new ArrayList<>();
for(int i=0;i<20;i++) {
itemList.add("Item "+i);
}
return itemList;
}
}
And the layout for the fragment is just a recyclerview fragment_recycler.xml:
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
The adapter and the viewholder for the recycler are the same as the article, and they doesn't affect the behavior.
What is wrong with the code?
UPDATE:
A Michał Z. below pointed out. What was missing is the paddingTop and clipptoPadding on the Recyclerview view
So the final xml should be:
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize"
android:clipToPadding="false"/>
And to solve the statusbar overlapping problem, it is needed to add a "fitsystemwindows" = "true" element on the activity layout. So it must be as the following:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<FrameLayout android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<include layout="#layout/toolbar_actionbar" />
</FrameLayout>
UPDATE2
The fitSystemWindows is only needed if the theme is setting the statusbar as translucent
Your fragment_recycler.xml file is missing paddingTop and clipToPadding attributes.
It should look like this:
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize"
android:clipToPadding="false"/>
And also remove clipToPadding from your toolbar_actionbar.xml.