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Why firebase recyclerview is not working correctly?

I try to open each video when I click on them but what I get instead is only the second video (sometimes first video). For example, when I click on "16 best video ideas for small business" I want it to open that particular video. But what I get instead is "this tiny camera can show the world from a bug's point of view. I think the problem occurs because of for loop inside query in UserHomeVideoAdapter.
UserHomeVideoAdapter.java:
public class UserHomeVideoAdapter extends FirestoreRecyclerAdapter<FollowList, UserHomeVideoAdapter.UserVideoHolder> {
Context context;
final FirebaseFirestore db = FirebaseFirestore.getInstance();
String thumbUrl, videoTitle, videoUrl, videoDesc, videoId, publisherId;
Video video;
public UserHomeVideoAdapter(#NonNull #NotNull FirestoreRecyclerOptions<FollowList> options, Context context) {
super(options);
this.context = context;
}
#Override
protected void onBindViewHolder(#NonNull #NotNull UserVideoHolder holder, int position, #NonNull #NotNull FollowList model) {
Query query = db.collection("Videos").whereEqualTo("publisherId", model.getUserId());
query.get().addOnCompleteListener(task -> {
if (task.isSuccessful()) {
if (task.getResult() != null) {
for (QueryDocumentSnapshot documentSnapshot : task.getResult()) {
video = documentSnapshot.toObject(Video.class);
Log.d("Data", documentSnapshot.getId() + " => " + documentSnapshot.getData());
thumbUrl = video.getThumbUrl();
videoTitle = video.getVideoTitle();
videoUrl = video.getVideoUrl();
videoDesc = video.getVideoDesc();
videoId = video.getVideoId();
publisherId = video.getPublisherId();
}
if (task.getResult().size() != 0) {
Glide.with(context).load(model.getUserImageUrl()).into(holder.userProfileImage);
Glide.with(context).load(thumbUrl).into(holder.videoImageView);
holder.videoTitle.setText(videoTitle);
holder.mainContainerVideo.setVisibility(View.VISIBLE);
} else if (task.getResult().size() == 0) {
holder.mainContainerVideo.getLayoutParams().height = 0;
holder.mainContainerVideo.getLayoutParams().width = 0;
}
}
} else {
Toast.makeText(context, String.valueOf(task.getException()), Toast.LENGTH_SHORT).show();
}
}).addOnFailureListener(e -> Toast.makeText(context, e.getLocalizedMessage(), Toast.LENGTH_SHORT).show());
holder.videoContainer.setOnClickListener(v -> {
Intent intent = new Intent(context, VideoActivity.class);
intent.putExtra("videoPublisherUserName", model.getUserName());
intent.putExtra("thumbUrl", thumbUrl);
intent.putExtra("videoPublisherEmail", model.getUserEmail());
intent.putExtra("videoUrl", videoUrl);
intent.putExtra("videoId", videoId);
intent.putExtra("videoPublisherFullName", model.getUserFullName());
intent.putExtra("videoPublisherId", publisherId);
context.startActivity(intent);
});
}
#NonNull
#NotNull
#Override
public UserVideoHolder onCreateViewHolder(#NonNull #NotNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(context).inflate(R.layout.video_cell, parent, false);
return new UserVideoHolder(v);
}
public static class UserVideoHolder extends RecyclerView.ViewHolder {
RelativeLayout videoContainer, mainContainerVideo;
CircleImageView userProfileImage;
TextView videoTitle;
ImageView videoImageView;
public UserVideoHolder(#NonNull #NotNull View itemView) {
super(itemView);
mainContainerVideo = itemView.findViewById(R.id.mainContainerVideo);
videoContainer = itemView.findViewById(R.id.videoContainer);
userProfileImage = itemView.findViewById(R.id.userProfileImage);
videoTitle = itemView.findViewById(R.id.videoTitle);
videoImageView = itemView.findViewById(R.id.videoImageView);
}
}
}
I logged videoId inside that is assigned inside for loop. Sometimes it returns ids in this order "1"; "2" and sometimes it returns like this "2"; "1". When it returns in this order "1"; "2" click opens second video even if I click first video and when it returns like this "2"; "1" click opens first video even if I click second video.
If you need additional code to solve the problem please ask and I will provide it as soon as possible. Any help is appreciated. Thanks

The short answer is that onBindViewHolder() is trying to do too much. From the documentation:
Called by RecyclerView to display the data at the specified position. This method should update the contents of the ViewHolder#itemView to reflect the item at the given position.
In other words, onBindViewHolder() is only responsible for one single item in the RecyclerView. However, you are trying to fetch all of the data for every element in the list. Instead, you should fetch the data external to your adapter and pass it in as a parameter. Then onBindViewHolder() should update the UI elements of a view inside the RecyclerView to display whatever you want for one single item.
Google has a great example CustomerAdapter. First, the constructor takes the list of data that will be displayed:
public CustomAdapter(String[] dataSet) {
mDataSet = dataSet;
}
Then onbindViewHolder() is only responsible for setting what is displayed in the UI of a single item in the RecyclerView:
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
Log.d(TAG, "Element " + position + " set.");
// Get element from your dataset at this position and replace the contents of the view
// with that element
viewHolder.getTextView().setText(mDataSet[position]);
}
It does NOT try to get data or loop over a list or anything else. All of that is someone else's responsibility.

get Array from another class and show it to a snackbar

I tried to get a array from an adapter from my code
here is the array that i wanted to get from my adapter, named MakananAdapter :
private int[] JumlahPesan = {0,0,0,0};
The array is changing constantly since user will be deciding the amount that they want, here is the onBindViewHolder code:
public void onBindViewHolder(#NonNull viewHolder holder, final int position) {
ImageView ivMakanan = holder.ivMakanan;
TextView tvNamaHarga = holder.tvNamaMakanan;
TextView tvKetersediaan = holder.tvKetersediaan;
TextView tvHarga = holder.tvHargaMakanan;
final TextView tvPesanan = holder.tvJumlahPesanan;
Button btnTambah = holder.btnTambah;
Button btnKurang = holder.btnKurang;
ivMakanan.setImageResource(makanans.get(position).getGambarMakanan());
tvNamaHarga.setText(makanans.get(position).getNamaMakanan());
tvKetersediaan.setText("Stok : " + makanans.get(position).getStatusMakanan());
tvHarga.setText("Harga : " + makanans.get(position).getHargaMakanan());
btnTambah.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
JumlahPesan[position]++;
tvPesanan.setText(String.valueOf(JumlahPesan[position]));
}
});
btnKurang.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
JumlahPesan[position]--;
tvPesanan.setText(String.valueOf(JumlahPesan[position]));
}
});
}
as you can see i make a button that increase and decrease the data of the array
and i tried to get the array data to my activity, but i still get error.
my activity named PilihMakananActivity.class
here is the array to save the data from the adapter
private int[] Pesanan = {0,0,0,0};
and i tried to get the data in onResume
protected void onResume() {
super.onResume();
com.example.iotforcanteen.adapter.MakananAdapter coba = null;
for (int i = 0; i<4 ; i++) {
Pesanan [i]= coba.AmbilJumlahPesanan(i);
}
}
and i tried to show it in a snackbar like this
btnKonfirmasi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Snackbar.make(v, Pesanan[0] + Pesanan[1] + Pesanan[2] + Pesanan[3],Snackbar.LENGTH_SHORT).show();
}
});
Im so sorry if the code is so messy, because im new to android development.so is there any way to fix this error?

It has error because you set to your adapter null value in onResume .
But in general I assume you use RecyclerView in code so the steps for using RecyclerView is important, first you must set LayoutManager for RecyclerView. Then make an adapter and set it to RecyclerView and I recommend you to do this steps in onCreate not onResume.
Here is a little example
RecyclerView recyclerView = findViewById(R.id.rec);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
adapter = new MyRecyclerViewAdapter(this, list);
recyclerView.setAdapter(adapter);
Also make your array in adapter public or write getter for it. After calling setAdapter for RecyclerView, you can get your data in adapter. For example you can define a Button and in OnClickListener get the desired array(here is JumlahPesan) in adapter

you aren't initiating this adapter (null) and few lines below trying to access data from it, this is NullPointerException
com.example.iotforcanteen.adapter.MakananAdapter coba = null;
for (int i = 0; i<4 ; i++) {
Pesanan [i]= coba.AmbilJumlahPesanan(i);
}
make reference to already exitsting adapter atached to your ListView or RecyclerView, not freshly created and not initialised at all
note that onResume is called once at the beggining, thus your Pesanan won't have current data, only copy from start of Activity
maybe just get your values straightly when button pressed, without a copy of array in Activity:
btnKonfirmasi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Snackbar.make(coordinatorLayout,
adapterAttachedToView.AmbilJumlahPesanan(0) + " " +
adapterAttachedToView.AmbilJumlahPesanan(1) + " " +
adapterAttachedToView.AmbilJumlahPesanan(2) + " " +
adapterAttachedToView.AmbilJumlahPesanan(3),
Snackbar.LENGTH_SHORT).show();
}
});
note that Snackbar.make( should take View, in which Snackbar will appear, not clicked Button (you are passing v to Snackbar.make)

How to change the background color of a view from a different activity in android?

I am working on a Quiz app. First when a user opens the app they go to the MainActivity, from there when they press start they go to the Categories Activity , from there after selecting a category they go to the Sets Activity, from there after selecting a set the go to the Questions Activity and finally after completing all the questions they reach the Score Activity. Here in the score activity when the click on Done button they are redirected to the MainActivity. In the Score Activity i want to change the color of the Set that they completed to green instead of the default color. How can i do this? I created a sets item layout xml file and used an adapter to fill the gridview in the Sets Activity with views from the adapter. Currently i am getting a null object reference after clicking the Done button in the ScoreActivity.
Here is the code :
SetsAdapter.java
public class SetsAdapter extends BaseAdapter {
private int numOfSets;
public SetsAdapter(int numOfSets) {
this.numOfSets = numOfSets;
}
#Override
public int getCount() {
return numOfSets;
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(final int position, View convertView, final ViewGroup parent) {
View view;
if(convertView == null){
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.set_item_layout, parent, false);
}
else {
view = convertView;
}
view.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent questionIntent = new Intent(parent.getContext(), QuestionActivity.class);
questionIntent.putExtra("SETNUM", position +1);
parent.getContext().startActivity(questionIntent);
}
});
((TextView) view.findViewById(R.id.setNumber)).setText(String.valueOf(position+1));
return view;
}
}
SetsActivity.java
public class SetsActivity extends AppCompatActivity {
private GridView sets_grid;
private FirebaseFirestore firestore;
public static int categoryID;
private Dialog loadingDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sets);
Toolbar toolbar = (Toolbar)findViewById(R.id.set_toolbar);
setSupportActionBar(toolbar);
String title = getIntent().getStringExtra("CATEGORY");
categoryID = getIntent().getIntExtra("CATEGORY_ID",1);
getSupportActionBar().setTitle(title);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
sets_grid = findViewById(R.id.sets_gridView);
loadingDialog = new Dialog(SetsActivity.this);
loadingDialog.setContentView(R.layout.loading_progressbar);
loadingDialog.setCancelable(false);
loadingDialog.getWindow().setBackgroundDrawableResource(R.drawable.progress_background);
loadingDialog.getWindow().setLayout(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
loadingDialog.show();
firestore = FirebaseFirestore.getInstance();
loadSets();
}
private void loadSets() {
firestore.collection("Quiz").document("CAT" + String.valueOf(categoryID))
.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
#Override
public void onComplete(#NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot doc = task.getResult();
if (doc.exists()) {
long sets = (long) doc.get("SETS");
SetsAdapter adapter = new SetsAdapter(Integer.valueOf((int)sets));
sets_grid.setAdapter(adapter);
} else {
Toast.makeText(SetsActivity.this, "No Sets Exists!", Toast.LENGTH_SHORT).show();
finish();
}
} else {
Toast.makeText(SetsActivity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show();
}
loadingDialog.cancel();
}
});
}
#Override
public boolean onOptionsItemSelected(#NonNull MenuItem item) {
if(item.getItemId() == android.R.id.home)
finish();
return super.onOptionsItemSelected(item);
}
}
ScoreActivity.java
public class ScoreActivity extends AppCompatActivity {
private TextView score;
private Button done;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_score);
score = findViewById(R.id.score_tv);
done = findViewById(R.id.score_activity_done);
String score_str = getIntent().getStringExtra("SCORE");
final int setNum = getIntent().getIntExtra("SetNum", 1);
score.setText(score_str);
done.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Here is the issue I am facing
View view = findViewById(R.id.setNumber);
view.setBackgroundColor(Color.GREEN);
Intent mainIntent = new Intent(ScoreActivity.this, MainActivity.class);
startActivity(mainIntent);
ScoreActivity.this.finish();
}
});
}
}

As your activity Sequence is MainActivity -> Categories -> Sets -> Scores.
You've two options to change the color with two different life cycle of the change.
To change the color on a temporary basis, this will reset itself after closing the app or resrtating the 'Sets' activity. It can be done in two ways: Using Public Static Variable and using a public function.
To change the color on a permanent basis until the app is uninstalled/reinstalled. You should use SharedPreferences. SharedPreferences acts like a private data stored in device's memory for further use and it stays there unchanged until and unless the app is removed/data is cleared. Although, apps with root permission can access any app's SharedPreferences data and can modify it as well.You can use SharedPreferences as explained here. Or, you can use some library to access it an easy way. The way I use it in all my apps is TinyDB(it's just a java/kotlin file). This works as:
//store the value from ScoreActivity after completion as
TinyDB tinyDB = TinyDB(this);
tinyDB.putBoolean("isSet1Completed",true);
//access the boolean variable in SetsActivity to change the color of any set that
//is completed and if it's true, just change the color.
TinyDB tinyDB = TinyDB(this);
Boolean bool1 = tinyDB.getBoolean("isSet1Completed");
But, it's your choice what way you want to prefer.
Now, this was about the lifecycle of the change you'll do: Temp or Permanent. Now, we'll talk about how you change the color.
Using public static variable in Sets activity. What you can do is you can set the imageView/textview whose background you want to change as public static variable. Remember, this idea is not preferred as it causes memory leak but it's just easy.
Declare it as public static ImageView imageview;(or TextView) intialize it in the
onCreated() as imageView = finViewById(R.id.viewId); in Sets activity. Call
it as new SetsActivity().imageView.setBackgroundColor(yourColor); in ScoreActivity.
Second way is to create a public function in SetsAcitvity, putting the color change code in it, and then calling it from the ScoreActivity. Just declare it as public void changeColor(){ //your work} and call it from ScoreActivity as new SetsActivity().changeCOlor(). You can also pass some arguments to the function like setId.
I've provided you every thing you need. Rest you should figure out yourself to actually learn it and not copy it.

I think simply you add flag in MainActivity.
for example, add flag in MainActivity.
boolean isFromDone = false;
and when done clicked,
done.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Here is the issue I am facing
Intent mainIntent = new Intent(ScoreActivity.this, MainActivity.class);
mainIntent.putExtra("FromDone", true);
startActivity(mainIntent);
ScoreActivity.this.finish();
}
});
and in MainActivity, add this.
#Override
protected void onResume() {
super.onResume();
isFromDone = getIntent().getBooleanExtra("FromDone", false);
if(isFromDone) {
(TextView) view.findViewById(R.id.setNumber)).setBackgroundColor(Color.GREEN);
}
}

Suppose you have a Linear Layout in Activity A and you want to change it's background color from a button click which is present in Activity B.
Step 1 Create a class and declare a static variable.
class Util { private static LinearLayout mylayout ; }
Step 2
In the activity which is holding this layout, initialize it.
Util.mylayout = findviewbyid(R.id.linear);
Step 3Change the background color on button click from Activity B
onClick{
Util.mylayout.setBackgroundColor(Color.RED);
}

favorite button in android not working properly

Hii i'm making an app where i have small heart image onclick of that image i've set an onclick listener so when i click on that image it is replaced by another red coloured heart image.
so my problem is when i again click on red heart image it doesnt turn to its normal state which is blank heart vector image as i'm new in android i dont have much knowledge please if someone can guide.
my code for image onclick
#Override
public void onBindViewHolder(FeedViewHolder holder, int position) {
int image_id = images[position];
//holder.background_image_layout.setImageDrawable(null);
//holder.background_image_layout.setImageResource(image_id);
holder.background_image.setBackgroundResource(image_id);
}
#Override
public int getItemCount() {
return images.length;
}
public static class FeedViewHolder extends RecyclerView.ViewHolder {
CustomTextViewMedium first_text,second_text,third_text,fourth_text,fifth_text,sixth_text,
seventh_text;
ImageView favourite_image;
CardView primary_card;
LinearLayout background_image;
ImageView background_image_layout;
CircleImageView profile_image;
public FeedViewHolder(View itemView) {
super(itemView);
background_image = (LinearLayout)itemView.findViewById(R.id.background_image);
primary_card = (CardView)itemView.findViewById(R.id.primary_card);
first_text = (CustomTextViewMedium)itemView.findViewById(R.id.first_text);
second_text = (CustomTextViewMedium)itemView.findViewById(R.id.second_text);
third_text = (CustomTextViewMedium)itemView.findViewById(R.id.third_text);
fourth_text = (CustomTextViewMedium)itemView.findViewById(R.id.fourth_text);
fifth_text = (CustomTextViewMedium)itemView.findViewById(R.id.fifth_text);
sixth_text = (CustomTextViewMedium)itemView.findViewById(R.id.sixth_text);
seventh_text = (CustomTextViewMedium)itemView.findViewById(R.id.seventh_text);
favourite_image = (ImageView)itemView.findViewById(R.id.favourite_image);
background_image_layout = (ImageView) itemView.findViewById(R.id.background_image_layout);
profile_image = (CircleImageView)itemView.findViewById(R.id.profile_image);
favourite_image.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(favourite_image.isPressed()){
favourite_image.setImageResource(R.drawable.ic_heart);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
else {
favourite_image.setImageResource(R.drawable.ic_favorite_border_black_24dp);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
}
});
}
}

Use if condition like this :-
first globally define like this :-
boolean imageChange = true;
then do this in setOnClickListener like this :-
favourite_image.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(imageChange ){
favourite_image.setImageResource(R.drawable.ic_heart);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageChange = false;
}else {
favourite_image.setImageResource(R.drawable.ic_favorite_border_black_24dp);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageChange = true;
}
}
});

Problem is that favourite_image.isPressed() is not persistent state of the View. It will be true only while user holds its finger on the view.
To overcome this you have two similar options:
Option #1
Instead of checking isPressed you can check some other state, for example isSelected. Since this is ImageView you probably need to set the state manually on click.
public void onClick(View v) {
if(favourite_image.isSelected()){
favourite_image.setImageResource(R.drawable.ic_heart);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
favourite_image.setSelected(false)
}
else {
favourite_image.setImageResource(R.drawable.ic_favorite_border_black_24dp);
favourite_image.setScaleType(ImageView.ScaleType.CENTER_CROP);
favourite_image.setSelected(true)
}
}
Options #2
Use some simple boolean to keep track of the selected state, and set/chec its values similarity to above code.

notifyDataSetChanged() not working with custom Adapter View

I have seen this question answered a few times, however none of the fixes have worked for me, so i'm reaching out.
I have built an app that features the Diolor Swipeable Cards Library (here) and now am trying to implement Course Card Filters.
Essentially when a user clicks a course filter we want to change the data that is being fed to the adapter.
Currently I am trying to update the data and calling notifyDataSetChanged() on the adapter, expecting the cards to refresh to show the new data set, however am finding that it is not refreshing at all.
Any help with this would be hugely appreciated.
All code below is from my Main Activity.
I declare the data set that i will be feeding to the adapter at the top of the activity:
ArrayList<CourseCardModel> courseCardModelList;
then in my onCreate() method I instantiate the adapter, attach it to the view, and call a generateCourseCards() method which populates the courseCardModelList with objects pulled from a firebase database.
// Set up and assign card adapter
ca = new CustomCardAdapter(CardsActivity.this, android.R.layout.simple_list_item_1, generateCourseCards());
flingContainer.init(CardsActivity.this, ca);
generateCourseCards() method
private ArrayList<CourseCardModel> generateCourseCards() {
Toast.makeText(getApplicationContext(), "Retrieving Courses", Toast.LENGTH_LONG).show();
courseCardModelList = new ArrayList<CourseCardModel>();
dbref = FirebaseDatabase.getInstance().getReference().child("courses");
// Retrieve the course data from Firebase db and cast as Course object
dbref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
Log.e("Count " ,"" + snapshot.getChildrenCount());
for (DataSnapshot postSnapshot: snapshot.getChildren()) {
c = postSnapshot.getValue(Course.class);
System.out.println(c.getCourseName());
CourseCardModel model = new CourseCardModel();
model.setCourse(c);
courseCardModelList.add(model);
}
Collections.shuffle(courseCardModelList);
ca.notifyDataSetChanged();
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.e("The read failed: ", databaseError.getMessage());
}
});
return courseCardModelList;
}
Attempt to update the dataset (a simple shuffle for the time being) and refresh the cards
// Shuffle the collection and refresh the cards
Collections.shuffle(courseCardModelList);
ca.notifyDataSetChanged();
EDIT: added adapter code
public class CustomCardAdapter extends ArrayAdapter {
private TextView courseName, uniName, entryStandards, courseDuration, studyMode, qualification,
studentSatisfaction, gradProspects, t1, t2, t3, t4, t5, t6;
ArrayList<CourseCardModel> items;
View v;
LayoutInflater vi;
public CustomCardAdapter(Activity context, int resource, ArrayList<CourseCardModel> courses) {
super(context, resource, courses);
vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#NonNull
#Override
public View getView(int position, View convertView, ViewGroup parent) {
v = convertView;
if (v == null) {
v = vi.inflate(R.layout.course_card_inner_template, parent , false);
}
CourseCardModel c = (CourseCardModel) getItem(position);
if (c != null) {
courseName = (TextView) v.findViewById(R.id.courseCardCourseName);
uniName = (TextView) v.findViewById(R.id.courseCardUniName);
entryStandards = (TextView) v.findViewById(R.id.courseCardEntryStandards);
courseDuration = (TextView) v.findViewById(R.id.courseCardCourseDuration);
studyMode = (TextView) v.findViewById(R.id.courseCardStudyMode);
qualification = (TextView) v.findViewById(R.id.courseCardQualification);
studentSatisfaction = (TextView) v.findViewById(R.id.courseCardStudentSatisfaction);
gradProspects = (TextView) v.findViewById(R.id.courseCardGraduateProspects);
t1 = (TextView) v.findViewById(R.id.cardTV1);
t2 = (TextView) v.findViewById(R.id.cardTV2);
t3 = (TextView) v.findViewById(R.id.cardTV3);
t4 = (TextView) v.findViewById(R.id.cardTV4);
t5 = (TextView) v.findViewById(R.id.cardTV5);
t6 = (TextView) v.findViewById(R.id.cardTV6);
v.setBackgroundResource(R.drawable.newcard);
courseName.setText(c.getCourse().getCourseName());
uniName.setText(c.getCourse().getUniversity());
entryStandards.setText(c.getCourse().getEntryStandards());
courseDuration.setText(c.getCourse().getCourseDuration());
studyMode.setText(c.getCourse().getStudyMode());
qualification.setText(c.getCourse().getQualification());
studentSatisfaction.setText(c.getCourse().getStudentSatisfaction().toString() + " / 5");
gradProspects.setText(c.getCourse().getGradProspects() + " / 100");
}
if(position ==0)
{
//float alpha = (float) 0.8;
//v.setAlpha(alpha);
courseName.setVisibility(View.VISIBLE);
}
else if (position == 1){
// Prepare the View for the animation
v.setVisibility(View.VISIBLE);
float alpha = (float) 0.8;
float alpha2 = (float) 0.3;
courseName.setAlpha(alpha2);
uniName.setAlpha(alpha2);
entryStandards.setAlpha(alpha2);
courseDuration.setAlpha(alpha2);
studyMode.setAlpha(alpha2);
qualification.setAlpha(alpha2);
studentSatisfaction.setAlpha(alpha2);
gradProspects.setAlpha(alpha2);
t1.setAlpha(alpha2);
t2.setAlpha(alpha2);
t3.setAlpha(alpha2);
t4.setAlpha(alpha2);
t5.setAlpha(alpha2);
t6.setAlpha(alpha2);
v.setAlpha(alpha);
}
else {
v.setVisibility(View.INVISIBLE);
}
return v ;
}
public void updateData(ArrayList<CourseCardModel> courseCardModels) {
this.items = courseCardModels;
notifyDataSetChanged();
}
}

Problem is in this method.
public void updateData(ArrayList<CourseCardModel> courseCardModels) {
this.items = courseCardModels;
notifyDataSetChanged();
}
here you are giving another array reference to your adapter.
Just rewrite as below.
public void updateData(ArrayList<CourseCardModel> courseCardModels) {
this.items.clear();
this.items.addAll(courseCardModels);
notifyDataSetChanged();
}

Without adapter class provided my first guess would be that you messed the references up. Maybe you are shuffling the data that is not referenced from the adapter. Once you share your adapter's code, I'll update my answer.
== EDIT ==
Avoid referencing some external collection of data from adapter, and updating that referenced data. Updating adapter/list data should be done using adapter's interface and methods such as add(), addAll() or remove() It might happen that (parent) adapter makes clone/copy of your data and in that case updating external/referenced collection is not doing any good.

You're extending an ArrayAdapter which holds his own array of models (the array passed to the constructor). If you would like to update the items, do something like this:
ca.clear();
for (CourseCardModel object : courseCardModelList) {
ca.insert(object, ca.getCount());
}
ca.notifyDataSetChanged();
Or you can override the getItem method and return an item from your items array.
And another option would be extending BaseAdapter instead of the ArrayAdapter.