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Nested RecyclerView load second item with lag

I'm trying to make Recyclerview like Shareit app. It uses sticky header and something like Cardview. I searched and found somethings for implementing sticky header with itemdecoration and it's okay. But for Cardview part, I tried to make nested Recyclerview but performance was so bad, Because using two vertical Recyclerview is not good at all. Is there any better way to achieve this?
The problem with performance is for when i scroll down. It makes lag on creating second item in parent Recyclerview.
AppheaderAdapter:
#Override
public AppHeaderAdapter.HeaderHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_media_header, parent, false);
HeaderHolder headerHolder = new HeaderHolder(view);
return headerHolder;
}
class HeaderHolder extends RecyclerView.ViewHolder { //story
final ImageView arrow;
final TextView tarikh;
final TextView tedad;
final CheckBox tick;
final RecyclerView item_recyc;
HeaderHolder(View itemView) {
super(itemView);
arrow = itemView.findViewById(R.id.header_arrow);
tarikh = itemView.findViewById(R.id.header_tarikh);
tedad = itemView.findViewById(R.id.header_tedad);
tick = itemView.findViewById(R.id.header_tick);
item_recyc = itemView.findViewById(R.id.header_recyc);
}
}
#Override
public void onBindViewHolder(#NonNull AppHeaderAdapter.HeaderHolder headerHolder, int position) {
final AppHeader appHeader = appHeaders.get(position);
...
GridLayoutManager gridLayoutManager = new GridLayoutManager(context, span);
gridLayoutManager.setRecycleChildrenOnDetach(true);
headerHolder.item_recyc.setLayoutManager(gridLayoutManager);
headerHolder.item_recyc.setNestedScrollingEnabled(false);
AppItemAdapter adapter = new AppItemAdapter(context, appHeader.getAppList(), fr_parent, width);
headerHolder.item_recyc.swapAdapter(adapter, true);
...
}
item_media_header.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/header_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:background="#drawable/so_round_so_white"
app:cardCornerRadius="10dp"
app:cardElevation="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/header_arrow"
android:layout_width="30dp"
android:layout_height="30dp"
android:padding="8dp"
android:src="#drawable/header_arrow"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/header_tarikh"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="#dimen/fragment_file"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toRightOf="#id/header_arrow"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/header_tedad"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="2dp"
android:textColor="#AAAAAA"
android:textSize="#dimen/fragment_file"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toRightOf="#id/header_tarikh"
app:layout_constraintTop_toTopOf="parent" />
<CheckBox
android:id="#+id/header_tick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:button="#null"
android:clickable="false"
android:drawableRight="#drawable/file_checkbox"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/header_recyc"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</androidx.cardview.widget.CardView>
EDIT 1:
I find that just first Cardview is loaded and second one is not loaded until I scroll to end of first one and then load second CardView item and it lags because of second RecyclerView.
I found that Shareit use previous created adapter and just change its internal datalist, So i do that, but still has lag on second item.
Edite 2:
I use one time created adapter on all RecyclerView but still has lag.
Edit 3:
It's a known bug that innerRecyclerView load all items at first and that cause my lag too. because inner Recyclerview is inside NestedScrollView (RV) and it loads all content.Using constant height doesn't work, But I'll update question if I find something better.

You can achieve this with ConstraintLayout and Flow.
EDIT: Sorry, I just realised I wrote everything in Kotlin. If you cannot understand something I can try to translate it to Java.
xml:
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/constraintLayout"
...>
<androidx.constraintlayout.helper.widget.Flow
android:id="#+id/flow"
app:flow_wrapMode="aligned"
app:flow_horizontalStyle="spread_inside"
app:flow_maxElementsWrap="4"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Adding of items:
val constraintLayout = itemView.findViewById(R.id.constraintLayout)
val flow = itemView.findViewById(R.id.flow)
val items // items given to the viewHolder to display
val layoutInflater = LayoutInflater.from(context)
items.forEach { item ->
val view = // create item view, e.g. DataBinding, ...
view.id = ViewCompat.generateViewId()
constraintLayout.addView(root)
flow.addView(root)
}
}
// if there are less than 4 items you have to add invisible dummy items. Otherwise, the alignment will look different for these ViewHolders
if(items.size>=4) return
for (i in 0..(4-items.size)) {
val view = // create dummy view
view.id = ViewCompat.generateViewId()
constraintLayout.addView(root)
flow.addView(root)
}

So far, Using vertical RV inside vertical RV has bug. Because of inner RV make long height and outer RV has no idea of this, So it create just first Item, but all items in inner RV. using all solution on Stack O.F. had no effect!

How to increase the number of text in Android programmatically

I have a page in which I'm taking the START TIME and END TIME from DATABASE.
Let's say the START TIME is 7:00 and END TIME is 22:00
I want to use this START TIME and END TIME to show in my page as textview like 7:00 8:00 9:00 and sooo on till 22:00 as textview
Also I have an imageview that will also increase when the text increases.
How can I achieve this?
Also I want the result text in Horizontal Scroll View with Imageview at top and text view as bottom of each imageview
char first = StartTime.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
int l;
for( l = StartTimeint; l<=22; l++){
Log.d("SeatsPage", "Time is "+l);
}
timeofseats.setText(Integer.toString(l));
This is I have done so far but I'm getting 23 as a result, the textview is not increasing
This is my XML File
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:id="#+id/llMain"
android:layout_height="match_parent"
tools:context=".SeatsPagewithDB.SeatsPage">
<ImageView
android:id="#+id/imageView11"
android:layout_width="150px"
android:layout_height="150px"
android:layout_marginStart="28dp"
android:layout_marginEnd="326dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/seat" />
<TextView
android:id="#+id/timeofseats"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="40dp"
android:layout_marginTop="12dp"
android:layout_marginEnd="334dp"
android:background="#FF0000"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="7:00"
android:textColor="#fff"
android:textSize="20dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView11" />
</android.support.constraint.ConstraintLayout>
This is the result I am getting as layout
This what I want programmatically

The XML code that you write in your layout.xml file to create the UI is for static UI only. What you are asking is to create views dynamically during runtime. Although you can definitely create views using java code on a click of a button or something. But it is better to code less for the UI whenever possible and keep it separated from the program code. Instead use the tools given to us by the framework we are using.
In Android those tools include stuff like ListView, GridView and the newer and better RecyclerView. These views help you add other views dynamically to your UI in runtime. You define one of them or more (depending on your UI needs) once in your layout.xml and configure them using java code like any other view.
This is how you can use RecyclerView to achieve your goal. I can't explain everything how RecyclerView works and what each line of code does as it will make a very long post but I have tried to highlight main things briefly.
1. Add RecyclerView in your layout file.
activity_main.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=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
2. Create another layout file and define the template UI of the item that the RecyclerView is going to display. RecyclerView will populate each item that it holds with this layout.
item_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
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="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="#+id/imageView_alarm"
android:layout_width="90dp"
android:layout_height="90dp"
android:src="#drawable/alarm" />
<TextView
android:id="#+id/textView_Time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:background="#FF0000"
android:paddingLeft="8dp"
android:paddingRight="8dp"
android:text="Time"
android:textColor="#android:color/background_light"
android:textSize="24sp" />
</LinearLayout>
3. Create a ViewHolder class that extends from RecyclerView.ViewHolder. View holder is a RecyclerView related concept. In short it works as a wrapper around the view of a single item and aids in binding new data to the view of the item. Create a bind() function inside view holder to make your life easier.
EDIT: I have updated the class by implementing the View.OnClickListener interface, modified the constructor to pass in the context from onCreateViewHolder() and adding a setItemPosition() just for the sake to pass the item position number from onBindViewHolder() all over to here so we can use this position number in our onClick() method of the interface
MyViewHolder.java [UPDATED]
public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView textView;
private int itemPosition;
private Context mContext;
public MyViewHolder(#NonNull View itemView, Context context) {
super(itemView);
itemView.setOnClickListener(this);
mContext = context;
textView = itemView.findViewById(R.id.textView_Time);
}
void bind(String timeText)
{
textView.setText(timeText);
}
void setItemPosition(int position)
{
itemPosition = position;
}
#Override
public void onClick(View v) {
Toast.makeText(mContext, "You clicked item number: " + itemPosition , Toast.LENGTH_SHORT).show();
}
}
4. Create an Adapter class that extends from RecyclerView.Adapter. Adapter works as a bridge between the UI data and RecyclerView itself. An Adapter tells the RecyclerView what layout file to inflate and how many to inflate. RecyclerView job is to deal with how to inflate it on the UI.
EDIT : Just changed myViewHolder in onCreateViewHolder() to match the modified constructor of MyViewHolder. Added the call to setItemPosition() in the onBindViewHolder().
MyAdapter.java [UPDATED]
public class MyAdapter extends RecyclerView.Adapter {
List<String> timeIntervalList = new ArrayList<>();
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_view, parent, false);
MyViewHolder myViewHolder = new MyViewHolder(view , parent.getContext());
return myViewHolder;
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
MyViewHolder viewHolder = (MyViewHolder) holder;
viewHolder.setItemPosition(position);
viewHolder.bind(timeIntervalList.get(position));
}
#Override
public int getItemCount() {
return timeIntervalList.size();
}
public void addItem (String timeText)
{
timeIntervalList.add(timeText);
notifyItemInserted(getItemCount());
}
}
In this adapter you will see two functions. OnCreateViewHolder() inflates the view using the template layout file for a single item and OnBindViewHolder() binds new data to the default values of the of the view just created. The data used for binding is stored in a list inside this Adapter called the timeIntervalList. This list will hold your time interval strings so they can be updated on the view.
5. Finally, use this RecyclerView where you want to use it. Like in your MainActivity.java. RecyclerView needs to be told in what fashion to display the items (e.g list , grid etc ) using a LayoutManager. LinearLayoutManager will display items either vertically or horizontally. You can see I am using your logic to increment time from string and adding new views to RecyclerView using the addItem() function of the MyAdapter class.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private RecyclerView myRecyclerView;
private MyAdapter myAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myRecyclerView = findViewById(R.id.recyclerView);
myAdapter = new MyAdapter();
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this , LinearLayoutManager.HORIZONTAL, false);
myRecyclerView.setLayoutManager(linearLayoutManager);
myRecyclerView.setAdapter(myAdapter);
// This is how you will populate the recycler view
String START_TIME = "7:00";
String END_TIME = "22:00";
char first = START_TIME.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
int l;
for( l = StartTimeint; l<=22; l++){
// This is where new item are added to recyclerView.
myAdapter.addItem(l + ":00");
}
}
}
This is the final result.

Change your activity layout XML code as follows,
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:id="#+id/llMain"
android:layout_height="match_parent"
tools:context=".SeatsPagewithDB.SeatsPage">
<HorizontalScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
...
...>
<LinearLayout
android:id="#+id/container"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</HorizontalScrollView>
</android.support.constraint.ConstraintLayout>
Move the textview and imageview to another XML file let's call it item_view.xml (you can name it whatever you wish). we are doing so because the root view of this file will be reused.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView11"
android:layout_width="150px"
android:layout_height="150px"
app:srcCompat="#drawable/seat"/>
<TextView
android:id="#+id/timeofseats"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#FF0000"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="7:00"
android:textColor="#fff"
android:textSize="20dp"/>
</LinearLayout>
Now make following changes in your Java file
LinearLayout container = findViewById(R.id.container); // or rootView.findViewById() for custom View and Fragment
char first = StartTime.charAt(0);
int StartTimeint = Integer.parseInt(String.valueOf(first));
for(int l = StartTimeint; l<=22; l++){
Log.d("SeatsPage", "Time is "+l);
View view = LayoutInflater.from(container.getContext()).inflate(R.layout.item_view, null);
TextView timeofseats = view.findViewById(R.id.timeofseats);
timeofseats.setText(Integer.toString(l));
container.addView(view);
}

Slow scroll performance of ListView with drawables

I am using a custom ArrayAdapter to populate a ListView.
My adapter code:
public class LocationAdapter extends ArrayAdapter<Location> {
public LocationAdapter(#NonNull Context context, ArrayList<Location> locationArrayList) {
super(context, 0, locationArrayList);
}
static class ViewHolder {
public TextView nameText;
public TextView descriptionText;
public ImageView image;
}
#NonNull
#Override
public View getView(int position, #Nullable View listItemView, #NonNull ViewGroup parent) {
ViewHolder viewHolder;
// check if the existing view is being reused
if (listItemView == null) {
// if not, inflate the view using location_list_itemlist_item.xml
listItemView = LayoutInflater.from(getContext()).inflate(R.layout.location_list_item, parent, false);
// configure view holder
viewHolder = new ViewHolder();
viewHolder.nameText = listItemView.findViewById(R.id.name_text_view);
viewHolder.image = listItemView.findViewById(R.id.image_view);
viewHolder.descriptionText = listItemView.findViewById(R.id.description_text_view);
listItemView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) listItemView.getTag();
}
// getting Location object in this position in ArrayList
Location currentLocation = getItem(position);
// using ViewHolder to set text/images to views
viewHolder.nameText.setText(currentLocation.getName());
viewHolder.descriptionText.setText(currentLocation.getDescription());
viewHolder.image.setImageResource(currentLocation.getImageResourceId());
return listItemView;
}
}
My list item XML code, very simple:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/name_text_view"
android:layout_width="368dp"
android:layout_height="22dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:textColor="#android:color/white"
app:layout_constraintBottom_toBottomOf="#+id/image_view"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
tools:text="Oleviste church"
android:elevation="2dp" />
<ImageView
android:id="#+id/image_view"
android:layout_width="match_parent"
android:layout_height="160dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:contentDescription="#string/image_content_description"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/description_text_view"
android:layout_width="0dp"
android:layout_height="51dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/image_view"
tools:text="This modern museum is located inside a former seaplane hangar and boasts a submarine and an ice breaker among its exhibits." />
</android.support.constraint.ConstraintLayout>
</LinearLayout>
Also, my ListView XML code just in case:
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never"
android:scrollingCache="false"
android:animationCache="false"/>
I experience some stuttering when scrolling the view in the app. Note that the images that I use are local drawables.
So far I have tried the following:
Cropping the drawables in Photoshop to fit the desired aspect ratio - significant improvement in speed but still a bit slow.
Using ViewHolder - maybe marginal improvement in speed.
Adding attributes android:scrollingCache="false" and android:animationCache="false" to the ListView - maybe marginal improvement in speed.
Using ConstraintLayout instead of RelativeLayout - maybe marginal improvement in speed.
Any ideas what I should try next?

Just use RecyclerView from the support library instead of a ListView. That should improve performance.
Refer to this SO question for more insight.
Android Recyclerview vs ListView with Viewholder

I was able to solve the issue with ListView scrolling using Glide framework. It is a robust framework focused on making scrolling lists with any kind of images fast and smooth.
All I had to do was to modify build.gradle:
repositories {
mavenCentral()
}
dependencies {
implementation 'com.github.bumptech.glide:glide:4.7.1'
annotationProcessor 'com.github.bumptech.glide:compiler:4.7.1'
}
Then in my adapter code I removed the following line (as setImageresource is not used anymore to load drawables):
viewHolder.image.setImageResource(currentLocation.getImageResourceId());
And added the following line to load drawables using Glide:
Glide.with(getContext()).load(currentLocation.getImageResourceId()).into(viewHolder.image);
More detailed information on how to use Glide is provided in the documentation.

How to correctly use if statement for inflater null checker

After trying to create a CardView programmatically, a NullPointerException but I've used an if statement and the warning is gone, but I'm not sure what needs to go in else part of the if statement.
Method invocation 'inflate' may produce java.lang.NullPointerException
Java
//start of CardView
LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(LAYOUT_INFLATER_SERVICE);
if(inflater1 != null) {
View inflatedCardviewLayout = inflater.inflate(R.layout.my_cardview, new RelativeLayout(getContext()), false);
inflatedCardviewLayout.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.green));
TextView cv_tv1a = inflatedCardviewLayout.findViewById(R.id.cardview_titleA);
cv_tv1a.setText(getString(R.string.titleA));
ImageView imgPictogram = inflatedCardviewLayout.findViewById(R.id.image_pictogram);
imgPictogram.setImageResource(R.drawable.ic_pictogram);
TextView cv_tv1b = inflatedCardviewLayout.findViewById(R.id.cardview_titleB);
cv_tv1b.setText(getString(R.string.titleB));
} else {
//do something else
}
//end of CardView
XML
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/tools"
android:id="#+id/my_cardview"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/cardview_titleA"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="#+id/image_pictogram"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="#+id/cardview_titleB"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>

You should fix the NullPointerException since getting an inflater is a required use for your code. I mean fix by using LayoutInflator.from(parent context) instead of asking the system for one.
You should make a class so that you extend CardView, then use the context of when you create the view object to get the inflater. Also make sure to merge the CardView with the inflated layout!

ListView only shows first item

I want to display all items of an ArrayList<String> on a ListView. I use an ArrayAdapter<String> for this. The problem is that only the first item ('foo' in my example) of the ArrayList is shown. Can someone tell me why? Am I missing something?
I've made an minimal example using the generated code (Tabbed Action Bar Spinner Activity) from Android Studio 2.
My FooActivity:
public class FooActivity extends AppCompatActivity {
...
public static class PlaceholderFragment extends Fragment {
private ListView fooListView;
private ArrayAdapter<String> mAdapter;
...
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_foo, container, false);
fooListView = (ListView) rootView.findViewById(R.id.foo_list);
updateList();
return rootView;
}
private void updateList() {
ArrayList<String> strings = new ArrayList<>();
strings.add("foo");
strings.add("bar");
if (mAdapter == null) {
mAdapter = new ArrayAdapter<>(getContext(),
R.layout.item_foo,
R.id.foo_string,
strings);
fooListView.setAdapter(mAdapter);
} else {
mAdapter.clear();
mAdapter.addAll(strings);
mAdapter.notifyDataSetChanged();
}
}
}
My fragment_foo.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.foo.activities.FooActivity$PlaceholderFragment">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/foo_list"
android:layout_below="#+id/total_activities"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="10dp"
android:layout_alignParentBottom="true" />
</RelativeLayout>
And the item_foo.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/foo_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="some_string"
android:textSize="20sp"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</LinearLayout>
If it helps I can post the generated activity_foo.xml (I didn't made any changes there) and the complete FooActivity class too.

The Problem actually was my activity_foo.xml which had a NestedScrollView. I've added android:fillViewport="true" and now it shows every item.
My NestedScrollView now looks like this:
<android.support.v4.widget.NestedScrollView
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:fillViewport="true"/>

On any ListView, if you use android:layout_height="wrap_content", you're only going to see one item. Try android:layout_height="match_parent". If the ListView only takes up part of the layout, you'll need a LinearLayout with weights or a RelativeLayout with constraints. But wrap_content won't work for a height on a ListView, ever.

Your Listview look something like this
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/foo_list"
android:layout_marginTop="10dp"/>
I have removed from your list view android:layout_below="#+id/total_activities"
and
android:layout_alignParentBottom="true"

For others: It's okay to nest a ListView inside another layout, and it's also fine to use android:layout_height="wrap_content" on Layouts surrounding the ListView. (So long as the outer-most Layout allows for match_parent)
What is not fine, however, is when the TextView being used to populate the ListView is defined with layout_height="match_parent". It will cover up all of the subsequent rows after the first.
Bad:
<TextView
android:id="#+id/infoRow_textView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
Good:
<TextView
android:id="#+id/infoRow_textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>