Develop Reference

Why won't my CardView appear in my fragment?

I am following this tutorial on how to create Swipe Views using a View Pager and am trying to convert it to work with fragments.
My issue is that the cards are not appearing when I select my fragment.
I think the issue lies in this line of code
adapter = new Adapter(models, getActivity());
(originally adapter = new Adapter(models, this); in the tutorial), but I could be wrong.
I am relatively new to android studio and this is my first time using fragments, any help would be greatly appreciated!
Here is my code:
fragment_cards.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"
android:background="#android:color/background_light"
>
<androidx.viewpager.widget.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:foregroundGravity="center"
android:overScrollMode="never"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"></androidx.viewpager.widget.ViewPager>
<Button
android:id="#+id/button_shuffle"
android:text="SHUFFLE"
android:textColor="#fff"
android:background="#drawable/round"
android:paddingLeft="30dp"
android:paddingRight="30dp"
android:layout_marginBottom="60dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
app:layout_constraintBottom_toBottomOf="#+id/viewPager"
app:layout_constraintEnd_toEndOf="#+id/viewPager"
app:layout_constraintStart_toStartOf="#+id/viewPager">
</Button>
</androidx.constraintlayout.widget.ConstraintLayout>
item.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"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimary">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:cardCornerRadius="20dp"
android:layout_margin="8dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="300dp">
<ImageView
android:id="#+id/image"
android:src="#drawable/brochure"
android:scaleType="centerCrop"
android:layout_width="match_parent"
android:layout_height="200dp"/>
<TextView
android:id="#+id/title"
android:textColor="#262626"
android:layout_below="#id/image"
android:layout_marginTop="10dp"
android:layout_marginLeft="16dp"
android:text="Brochure"
android:textSize="16sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:id="#+id/desc"
android:layout_below="#id/title"
android:layout_marginTop="3dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:maxLines="3"
android:drawablePadding="10dp"
android:ellipsize="end"
android:text="Description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</RelativeLayout>
</androidx.cardview.widget.CardView>
</LinearLayout>
CardsFragment.java
package com.example.musicassistant;
import android.animation.ArgbEvaluator;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
public class CardsFragment extends Fragment {
ViewPager viewPager;
Adapter adapter;
List<Model> models;
Integer[] colors = null;
ArgbEvaluator argbEvaluator = new ArgbEvaluator();
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
models = new ArrayList<>();
models.add(new Model(R.drawable.brochure, "Brochure", "oooooo"));
models.add(new Model(R.drawable.sticker, "Sticker", "oooooo"));
models.add(new Model(R.drawable.poster, "Poster", "oooooo"));
models.add(new Model(R.drawable.namecard, "Namecard", "oooooo"));
adapter = new Adapter(models, getActivity());
viewPager = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
viewPager.setAdapter(adapter);
viewPager.setPadding(130,0,130,0);
Integer[] colors_temp = {
getResources().getColor(R.color.color1),
getResources().getColor(R.color.color2),
getResources().getColor(R.color.color3),
getResources().getColor(R.color.color4)
};
colors = colors_temp;
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (position < (adapter.getCount() -1) && position < (colors.length -1)) {
viewPager.setBackgroundColor(
(Integer) argbEvaluator.evaluate(
positionOffset,
colors[position],
colors[position + 1]
)
);
} else {
viewPager.setBackgroundColor(colors[colors.length - 1]);
}
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
return inflater.inflate(R.layout.fragment_cards, container, false);
}
}
Adapter.java
package com.example.musicassistant;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.viewpager.widget.PagerAdapter;
import java.util.List;
public class Adapter extends PagerAdapter {
private List<Model> models;
private LayoutInflater layoutInflater;
private Context context;
public Adapter(List<Model> models, Context context) {
this.models = models;
this.context = context;
}
#Override
public int getCount() {
return models.size();
}
#Override
public boolean isViewFromObject(#NonNull View view, #NonNull Object object) {
return view.equals(object);
}
#NonNull
#Override
public Object instantiateItem(#NonNull ViewGroup container, int position) {
layoutInflater = LayoutInflater.from(context);
View view = layoutInflater.inflate(R.layout.item, container, false);
ImageView imageView;
TextView title, desc;
imageView = view.findViewById(R.id.image);
title = view.findViewById(R.id.title);
desc = view.findViewById(R.id.desc);
imageView.setImageResource(models.get(position).getImage());
title.setText(models.get(position).getTitle());
desc.setText(models.get(position).getDesc());
container.addView(view, 0);
return view;
}
#Override
public void destroyItem(#NonNull ViewGroup container, int position, #NonNull Object object) {
container.removeView((View)object);
}
}
Model.java
package com.example.musicassistant;
public class Model {
private int image;
private String title;
private String desc;
public Model(int image, String title, String desc) {
this.image = image;
this.title = title;
this.desc = desc;
}
public int getImage() {
return image;
}
public void setImage(int image) {
this.image = image;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
}
It is worth noting that the fragment itself is working, as the button in it is appearing correctly.
The only issue is that my cards are not showing up at all.
Any help would be greatly appreciated as this is driving me absolutely insane!
Thank you very much for your time I greatly appreciate it,
Roman

Inflate will create a new layout object(view object) eveytime you use it so this is one view layout
viewPager = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
and you are returning a new view object which has nothing
return inflater.inflate(R.layout.fragment_cards, container, false);
so you need to store a single reference of view after inflating then use it and return it, as
View root = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
viewPager = root.findViewById(R.id.viewPager);
// ... code
return root;

How to make custom adapter?

I'm trying to make custom adapter for my small app, I got stuck in filling my rows with data, I can't find a good tutorial for that. I know how to use Simple Adapter and Array Adapter, but custom ones have some trouble.
I don't know how to implement it, and the online articles confused me, Please help me with the logic and what steps should I do implement.
package com.example.administrator.healthyfood;
import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ListView;
public class MainActivity extends AppCompatActivity {
ListView list;
String[] food = {"Dog","Cat","Cow","Fish","Frog","Bird","Rabbit","Horse","Chikcen"};
#Override
protected void onCreate(Bundle savedInstanceState) {
list = (ListView)findViewById(R.id.listView);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public class MyListViewAdapter extends BaseAdapter {
#Override
public int getCount() {
return food.lenght();
}
#Override
public long getItemId(int i) {
return 0;
}
#Override
public Object getItem(int i) {
return null;
}
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
return null;
}
}
}

activity_main.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=".MainActivity" >
<ListView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
</ListView>
</RelativeLayout>
custom.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:layout_width="255dp"
android:layout_height="wrap_content"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Video1"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#339966"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/detail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="video1"
android:textColor="#606060" />
</LinearLayout>
</LinearLayout>
<ImageView
android:id="#+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_launcher" />
</LinearLayout>
</LinearLayout>
Your MainActivity.java -
package com.example.sample;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
ListView l1;
String[] t1={"video1","video2"};
String[] d1={"lesson1","lesson2"};
int[] i1 ={R.drawable.ic_launcher,R.drawable.ic_launcher};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
l1=(ListView)findViewById(R.id.list);
l1.setAdapter(new dataListAdapter(t1,d1,i1));
}
class dataListAdapter extends BaseAdapter {
String[] Title, Detail;
int[] imge;
dataListAdapter() {
Title = null;
Detail = null;
imge=null;
}
public dataListAdapter(String[] text, String[] text1,int[] text3) {
Title = text;
Detail = text1;
imge = text3;
}
public int getCount() {
// TODO Auto-generated method stub
return Title.length;
}
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = getLayoutInflater();
View row;
row = inflater.inflate(R.layout.custom, parent, false);
TextView title, detail;
ImageView i1;
title = (TextView) row.findViewById(R.id.title);
detail = (TextView) row.findViewById(R.id.detail);
i1=(ImageView)row.findViewById(R.id.img);
title.setText(Title[position]);
detail.setText(Detail[position]);
i1.setImageResource(imge[position]);
return (row);
}
}
}
Hope this is enough for you.

You can create a simple Adapter class using these simple steps
make a java class
public class Wallet_Adapter extends RecyclerView.Adapter<Wallet_Adapter.ViewHolder>
{
LayoutInflater inflater;
List<Wallet_Model> modelclasslists;
public Wallet_Adapter(Context ctx, List<Wallet_Model> modelclasslists)
{
this.inflater=LayoutInflater.from(ctx);
this.modelclasslists=modelclasslists;
}
#NonNull
#Override
public Wallet_Adapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view=inflater.inflate(R.layout.layout_wallet,parent,false);
return new Wallet_Adapter.ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull Wallet_Adapter.ViewHolder holder, int position) {
holder.date.setText(modelclasslists.get(position).getDate());
holder.amount.setText(modelclasslists.get(position).getAmount());
holder.description.setText(modelclasslists.get(position).getDescription());
holder.type.setText(modelclasslists.get(position).getType());
}
#Override
public int getItemCount() {return modelclasslists.size(); }
public class ViewHolder extends RecyclerView.ViewHolder
{
TextView date,amount,description,type;
public ViewHolder(#NonNull View itemView)
{
super(itemView);
date=itemView.findViewById(R.id.dateans);
amount=itemView.findViewById(R.id.amountans);
description=itemView.findViewById(R.id.descriptionans);
type=itemView.findViewById(R.id.typeans);
}
}
}

Custom Listview activity keep crashing

So I have this custom list adapter and listview thingy and I can't seem to get it to work. I've spent a couple of days now trying to figure how to fix it. Change this change that, nothing seems to work. Any idea? thanks
MainActivity.class
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActvty";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_inventory_actvity);
Log.d(TAG, "onCreate, Started");
ListView resList = (ListView)findViewById(R.id.inListView);
resClass wood = new resClass("Wood", 10);
resClass iron = new resClass("Iron", 50);
resClass meat = new resClass("Meat", 5);
ArrayList<resClass> resArrayList = new ArrayList<>();
resArrayList.add(wood);
resArrayList.add(iron);
resArrayList.add(meat);
ResListAdapter rsAdapter = new ResListAdapter(this, R.layout.activity_inventory_actvity, resArrayList);
resList.setAdapter(rsAdapter);
}
}
resClass.class
public class resClass {
private String resType;
private int resCount;
public resClass(String resType, int resCount) {
this.resType = resType;
this.resCount = resCount;
}
public String getResType() {
return resType;
}
public void setResType(String resType) {
this.resType = resType;
}
public int getResCount() {
return resCount;
}
public void setResCount(int resCount) {
this.resCount = resCount;
}
}
ResListAdapter.class
I'm guessing there is something wrong with the adapter. But I'm not really sure.
import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;
class ResListAdapter extends ArrayAdapter<resClass>{
private static final String TAG = "ResListAdapter";
private Context mContext;
int mResource;
public ResListAdapter( Context context, int resource, ArrayList<resClass> objects) {
super(context, resource, objects);
mContext = context;
mResource = resource;
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
String resType = getItem(position).getResType();
int resCount = getItem(position).getResCount();
resClass res = new resClass(resType, resCount);
LayoutInflater rsInflater = LayoutInflater.from(mContext);
convertView = rsInflater.inflate(mResource, parent, false);
TextView resTypeView = (TextView)convertView.findViewById(R.id.res_name);
TextView resCountView = (TextView)convertView.findViewById(R.id.res_count);
resTypeView.setText(resType);
resCountView.setText(Integer.toString(resCount));
return convertView;
}
}
The xml files
MainActivity
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="p_darkness.lonemandevelopmentstudio.com.p_darkness.MainActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="8dp"
android:id="#+id/inListView"/>
</RelativeLayout>
Custom layout for the listview
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="horizontal"
android:weightSum="100"
android:layout_height="match_parent">
<TextView
android:id="#+id/res_name"
android:textColor="#000"
android:textSize="17sp"
android:layout_width="wrap_content"
android:layout_height="60dp"
android:gravity="center"
android:layout_weight="50"
android:text="res_name"
android:textAlignment="center"/>
<TextView
android:id="#+id/res_count"
android:textColor="#000"
android:textSize="15sp"
android:textAlignment="center"
android:layout_width="wrap_content"
android:layout_height="60dp"
android:gravity="center"
android:layout_weight="50"
android:text="res_count"
/>
</LinearLayout>
It's been really frustrating guys hope I can find the solution by asking this time.

RecyclerView does not load data, shows nothing

I'm a beginner with Android and struggling with the implementation of a RecyclerView. Was working through a tutorial and changing the values to what I need. But when I start, the view stays empty. As far as I was planning, it was supposed to show 20 times the same item for the moment.
ExerciseList.java (Start Activity):
package com.example.erik.orlandoapp;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
public class ExerciseList extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTitle(getString(R.string.title_activity_exercise_list));
setContentView(R.layout.activity_exercise_list);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
}
}
ExerciseBlock.java:
package com.example.erik.orlandoapp;
import java.util.ArrayList;
import java.util.List;
public class ExerciseBlock {
private String title;
private int difficulty;
private int exerciseId;
private static int lastId = 0;
public ExerciseBlock(String title, int difficulty, int exerciseId) {
this.title = title;
this.difficulty = difficulty;
this.exerciseId = exerciseId;
}
public String getTitle() {
return title;
}
public int getDifficulty() {
return difficulty;
}
public int getExerciseId() {
return exerciseId;
}
public static ArrayList<ExerciseBlock> createContactsList(int numContacts) {
ArrayList<ExerciseBlock> exerciseBlocks = new ArrayList<ExerciseBlock>();
for (int i = 1; i <= numContacts; i++) {
exerciseBlocks.add(new ExerciseBlock("Title",1,1));
}
return exerciseBlocks;
}
}
ExerciseBlockAdapter.java:
package com.example.erik.orlandoapp;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class ExerciseBlockAdapter extends RecyclerView.Adapter<ExerciseBlockAdapter.ViewHolder> {
private List<ExerciseBlock> exList;
private Context mContext;
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Context context = parent.getContext();
LayoutInflater inflater = LayoutInflater.from(context);
View contactView = inflater.inflate(R.layout.exercise_item, parent, false);
ViewHolder viewHolder = new ViewHolder(contactView);
return viewHolder;
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
ExerciseBlock exBlock = exList.get(position);
TextView textView = viewHolder.getTxtDiff();
textView.setText(exBlock.getDifficulty());
textView = viewHolder.getTxtExercise();
textView.setText(exBlock.getExerciseId());
}
#Override
public int getItemCount() {
return exList.size();
}
public ExerciseBlockAdapter(Context context, List<ExerciseBlock> exList) {
this.exList = exList;
this.mContext = context;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
private TextView txtExercise;
private TextView txtDiff;
public TextView getTxtExercise() {
return this.txtExercise;
}
public TextView getTxtDiff() {
return this.txtDiff;
}
public ViewHolder(View itemView) {
super(itemView);
txtDiff = (TextView) itemView.findViewById(R.id.txtExDiff);
txtExercise = (TextView) itemView.findViewById(R.id.txtExName);
}
}
}
UserListActivity:
package com.example.erik.orlandoapp;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import java.util.ArrayList;
public class UserListActivity extends AppCompatActivity {
ArrayList<ExerciseBlock> exerciseBlocks;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
RecyclerView rvContacts = (RecyclerView) findViewById(R.id.exerciseList);
exerciseBlocks = ExerciseBlock.createContactsList(20);
ExerciseBlockAdapter adapter = new ExerciseBlockAdapter(this, exerciseBlocks);
rvContacts.setAdapter(adapter);
rvContacts.setLayoutManager(new LinearLayoutManager(this));
}
}
activity_exercise_list.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
android:fitsSystemWindows="true"
tools:context="com.example.erik.orlandoapp.ExerciseList">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/exerciseList"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="20dp"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
exercise_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:weightSum="1">
<TextView
android:id="#+id/txtExName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Whatever" />
<TextView
android:id="#+id/txtExDiff"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorDifEasy"
android:paddingBottom="6dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="6dp"
android:text="Leicht"
android:textSize="10sp" />
</LinearLayout>
Thanks a lot!

I don't see UserListActivity calling setContentView()
Either put this code inside ExersiceList Activity
RecyclerView rvContacts = (RecyclerView) findViewById(R.id.exerciseList);
exerciseBlocks = ExerciseBlock.createContactsList(20);
ExerciseBlockAdapter adapter = new ExerciseBlockAdapter(this, exerciseBlocks);
rvContacts.setAdapter(adapter);
rvContacts.setLayoutManager(new LinearLayoutManager(this));
or call setContentView(R.layout.activity_exercise_layout) on Your UserListActivity

StaggeredGrid RecyclerView not showing anything

I'm trying to inflate a RecyclerView which has as StaggeredGrid Layout, but it is not showing anything. I've pretty much copied previous code I've used before for the RecyclerView so I'm kind of stumped.
In MuseumStoriesViewHolder.onCreateViewHolder() the return of holder has the following value ViewHolder{337ec22b position=-1 id=-1, oldPos=-1, pLpos:-1 unboundundefined adapter position no parent} I'm not sure if this is realated, but it was something that seemed off to me.
It also might help to know that the fragment I'm inflating this RecyclerView is a nested Fragment.
Any help would be greatly appreciated.
MuseumFragment
package com.example.android.radiobuttontestproject.fragments;
import android.app.Activity;
import android.os.Bundle;
import android.app.Fragment;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.android.radiobuttontestproject.R;
import com.example.android.radiobuttontestproject.adapters.MuseumStoriesAdapter;
import com.example.android.radiobuttontestproject.helpers.pojo.StoryObject;
import com.example.android.radiobuttontestproject.test.SampleDataFactory;
import java.util.List;
import butterknife.Bind;
import butterknife.ButterKnife;
public class MuseumFragment extends Fragment {
private List<StoryObject> storyObjectList;
private StaggeredGridLayoutManager storyGridLayoutManager;
private MuseumStoriesAdapter storyAdapter;
#Bind(R.id.stories_recycler_view) RecyclerView storiesRecyclerView;
public static MuseumFragment newInstance() {
MuseumFragment fragment = new MuseumFragment();
Bundle args = new Bundle();
fragment.setArguments(args);
return fragment;
}
public MuseumFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_museum, container, false);
ButterKnife.bind(this, view);
//Sets up the stories
SampleDataFactory sampleDataFactory = new SampleDataFactory();
storyObjectList = sampleDataFactory.getSampleStories(
getResources().getStringArray(R.array.test_titles_for_grid_museum1),
getResources().getStringArray(R.array.test_desc_for_grid_museum1));
storyGridLayoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
storiesRecyclerView.setLayoutManager(storyGridLayoutManager);
storyAdapter = new MuseumStoriesAdapter(getActivity().getApplicationContext(), storyObjectList);
storiesRecyclerView.setAdapter(storyAdapter);
return view;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
#Override
public void onDetach() {
super.onDetach();
}
}
MuseumStoriesAdapter
package com.example.android.radiobuttontestproject.adapters;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import com.example.android.radiobuttontestproject.R;
import com.example.android.radiobuttontestproject.helpers.pojo.StoryObject;
import java.util.List;
public class MuseumStoriesAdapter extends RecyclerView.Adapter<MuseumStoriesAdapter.MuseumStoriesViewHolder> {
private List<StoryObject> itemList;
private LayoutInflater inflater;
private Context context;
public MuseumStoriesAdapter(Context context, List<StoryObject> itemList) {
this.itemList = itemList;
this.context = context;
inflater = LayoutInflater.from(this.context);
}
#Override
public MuseumStoriesViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View view = inflater.inflate(R.layout.view_box_small, viewGroup, false);
MuseumStoriesViewHolder holder = new MuseumStoriesViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(MuseumStoriesViewHolder holder, int position) {
holder.title.setText(itemList.get(position).getTitle());
holder.desc.setText(itemList.get(position).getDescription());
}
#Override
public int getItemCount() {
return itemList.size();
}
class MuseumStoriesViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView type,title,desc;
public MuseumStoriesViewHolder(View itemView) {
super(itemView);
//Tried Butterknife, but it doesn't seem like it was working in the view holder. - Peter
type = (TextView) itemView.findViewById(R.id.small_box_type);
title = (TextView) itemView.findViewById(R.id.small_box_title);
desc = (TextView) itemView.findViewById(R.id.small_box_desc);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
Toast.makeText(view.getContext(), "Clicked Position = " + getPosition(), Toast.LENGTH_SHORT).show();
}
}
}
fragment_museum.xml
<ScrollView
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"
tools:context="com.example.android.radiobuttontestproject.fragments.MuseumFragment">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="1">
<TextView
android:id="#+id/museum_header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/header_margin"
android:gravity="center"
android:textSize="#dimen/font_larger"
android:text="#string/museum_header" />
<android.support.v7.widget.RecyclerView
android:id="#+id/stories_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
view_box_small.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="wrap_content"
android:layout_margin="#dimen/small_box_margin"
android:background="#color/small_box_background_color">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<!--TODO Make layout_height wrap contenet -->
<ImageView
android:layout_width="match_parent"
android:layout_height="120dp"
android:background="#color/test_color2"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:src="#drawable/abc_btn_rating_star_off_mtrl_alpha"
/>
</FrameLayout>
<TextView
android:id="#+id/small_box_type"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="#dimen/font_small"
android:textColor="#color/font_red"
android:text="Object"
/>
<TextView
android:id="#+id/small_box_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="#dimen/font_large"
android:textColor="#color/font_black"
android:text="Sample Text Here"
/>
<TextView
android:id="#+id/small_box_desc"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="#dimen/font_normal"
android:textColor="#color/font_black"
android:textStyle="italic"
android:text="Sample Text Here"
/>
</LinearLayout>