I'm new to Android. I'm trying to get data from Parse and update the adapter.
I'm extending my adapter from Array Adapter.
In my adapter, I have an image and an text field.
Issues I have: I'm seeing only the last element in the array in my array adapter.
This is my basic set up:
My parse method contains an inner anonymous class findCallBackMethod.
In the done method of the parse,
I'm getting the data from Parse and creating a new object to add it to my array list.
This array list is shown in my adapter.
I'm able to see my entire array result list within my done method.
I searched onto stack overflow and followed some suggestions on creating and setting the adapter within this done method.
Tried so far:
Making the adapter within the for loop. This for loop gets the data from Parse.
Tried creating a global instance for ArrayList so the arrayList is visible.
(Didn't help at all)
I cannot make my array list final as I'll creating this array list within this for loop.
Question: How do I make my adapter update the list from within this anonymous inner class?
what am i missing here?
Any help is appreciated.
Thanks!
Below is my sample of my code:
public void searchPlayer(String playerFirstName)
{
ParseQuery<ParseObject> query_players = ParseQuery.getQuery("myDataFile");
try {
query_players.whereMatches("FirstName","Patrick");
} catch (NullPointerException e) {
e.printStackTrace(); // change this to meaningful message
}
query_players.findInBackground(new FindCallback<ParseObject>()
{
public String shortName;
public int playerID;
#Override
public void done(List<ParseObject> playerList, com.parse.ParseException e) {
if (e == null)
{
d("TAG", "Retrieved: size = " + playerList.size());
for(int i=0;i<playerList.size();i++)
{
newPlayer = MySingleton.getInstance().newPlayer;
arrayOfPlayers = MySingleton.getInstance().arrayOfPlayers;
// short name is abbreviated name; got it from Parse
// create a single player
String shortName = playerList.get(i).getString("ShortName");
String firstName = playerList.get(i).getString("FirstName");
String lastName = playerList.get(i).getString("LastName");
playerID = playerList.get(i).getInt("PlayerID");
Log.d("Player", "short name: " + shortName);
//newPlayer = new Player();
// if (newPlayer != null) {
newPlayer.setPlayerShortName(shortName);
newPlayer.setPlayerFirstName(firstName);
newPlayer.setPlayerLastName(lastName);
newPlayer.setPlayerID(playerID);
newPlayer.setPhotoUrl(playerList.get(i).getString("PhotoUrl"));
Log.d("Player", "the photo url = : " + newPlayer.getPhotoUrl());
//adding the new player to the array
if (newPlayer != null) {
d("Player", "adding the new player to array list ");
arrayOfPlayers.add(newPlayer);
Log.d("Player", "the new player's last name in the arrayList " + arrayOfPlayers.get(i).getPlayerLastName());
Log.d("Player", "the new player's photo url in the arrayList " + arrayOfPlayers.get(i).getPhotoUrl());
}
//printing the playerlist:
for(Player x:arrayOfPlayers) {
Log.d(TAG,"printing the list of player's last name within the for: " + x.getPlayerLastName());
}
lvPlayerList = (ListView) view.findViewById(R.id.lvPlayerList);
aPlayerListAdapter= new PlayerSearchListArrayAdapter(getActivity(),arrayOfPlayers);
lvPlayerList.setAdapter(aPlayerListAdapter);
aPlayerListAdapter.notifyDataSetChanged();
}// end of for
/* THIS WORKS WITHIN THE INNER CLASS --- TESTED)
Log.d("Player", "the array size " + arrayOfPlayers.size());
Log.d("Player", "the player id from the arrayList " + arrayOfPlayers.get(8).getPlayerID());
Log.d("Player"," the activity in the player fragment: " + getActivity());
*/
} //end of (e==null)
else
{
d("score", "Error: " + e.getMessage());
//playerArrayList = null;
}
}// end of done
}); // end of inner class
My Adapter class:
// Adapter for the list: inflates player_list_item
public class PlayerSearchListArrayAdapter extends ArrayAdapter<Player>{
public static final String TAG = "PLAYER_SEARCH_LIST_ADAPTER";
private ImageView imvPlayer;
private TextView tvPlayerFullName;
List<Player> playerList;
LayoutInflater mInflater;
public PlayerSearchListArrayAdapter(Context context,List<Player> playerList) {
//super(context, 0 , playerList);
super(context,0,playerList);
mInflater = LayoutInflater.from(context);
this.playerList = playerList;
}
public View getView(int position, View convertView, ViewGroup parent) {
//return super.getView(position, convertView, parent);
Log.d(TAG,"inside adapter");
Log.d(TAG,"activity = " + getContext());
// get the data item for position
Player player = getItem(position);
Log.d(TAG,"player list size from within the adapter: = " + playerList.size());
Log.d(TAG,"player's last name = " + player.getPlayerLastName());
// find if the view exists. what that means if we reached the max limit
// of items to view on the screen, then Android starts to recycle the
// previous viewable list items.
// If the view does not exist, we have to create one through the inflater
View v = convertView;
if (v == null)
{
LayoutInflater inflater = LayoutInflater.from(getContext());
// v = inflater.inflate(R.layout.player_list_item,parent,false);
// check if to attach to root
v = inflater.inflate(R.layout.player_list_item,parent,false);
}
// find the ids in the tweet_item.xml
ImageView imvPlayer = (ImageView)v.findViewById(R.id.imvPlayer);
TextView tvPlayerFullName = (TextView)v.findViewById(R.id.tvPlayerFullName);
// populate the items
// ImageUri is the url of the image
String imageUri = player.getPhotoUrl();
Picasso.with(getContext()).load(imageUri).into(imvPlayer);
tvPlayerFullName.setText(player.getPlayerShortName());
return v;
}
}
My usage of singleton in this case is not correct.
Fixed the issue. I was creating the adapter and the array every single time the loop iterates.
Changing that solved the issue.
Related
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.
I found this multilevel expandable listview which is very accurate with my project, but I also want to add a different toast to every third level (which is the last layer of view) child items. I tried this:
expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
#Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
Toast.makeText(thirdLevelq1.put(q1[0] this, "The first child" , Toast.LENGTH_LONG).show();
return false;
}
});
But it gives error. I even tried to use same toast text to every childItem, app installed but crashed when I opened the adapter. So, how to add them properly?
Java:
package com.bacon.expandablelistview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ExpandableListView;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private ExpandableListView expandableListView;
String[] parent = new String[]{"What is View?", "What is Layout?", "What is Dynamic Views?"};
String[] q1 = new String[]{"List View", "Grid View"};
String[] q2 = new String[]{"Linear Layout", "Relative Layout"};
String[] q3 = new String[]{"Recycle View"};
String[] des1 = new String[]{"A layout that organizes its children into a single horizontal or vertical row. It creates a scrollbar if the length of the window exceeds the length of the screen."};
String[] des2 = new String[]{"Enables you to specify the location of child objects relative to each other (child A to the left of child B) or to the parent (aligned to the top of the parent)."};
String[] des3 = new String[]{"This list contains linear layout information"};
String[] des4 = new String[]{"This list contains relative layout information,Displays a scrolling grid of columns and rows"};
String[] des5 = new String[]{"Under the RecyclerView model, several different components work together to display your data. Some of these components can be used in their unmodified form; for example, your app is likely to use the RecyclerView class directly. In other cases, we provide an abstract class, and your app is expected to extend it; for example, every app that uses RecyclerView needs to define its own view holder, which it does by extending the abstract RecyclerView.ViewHolder class."};
LinkedHashMap<String, String[]> thirdLevelq1 = new LinkedHashMap<>();
LinkedHashMap<String, String[]> thirdLevelq2 = new LinkedHashMap<>();
LinkedHashMap<String, String[]> thirdLevelq3 = new LinkedHashMap<>();
/**
* Second level array list
*/
List<String[]> secondLevel = new ArrayList<>();
/**
* Inner level data
*/
List<LinkedHashMap<String, String[]>> data = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//The problem starts here
expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
#Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
Toast.makeText(getApplicationContext(), "The first child", Toast.LENGTH_LONG).show();
return false;
}
});
setUpAdapter();
}
private void setUpAdapter() {
secondLevel.add(q1);
secondLevel.add(q2);
secondLevel.add(q3);
thirdLevelq1.put(q1[0], des1);
thirdLevelq1.put(q1[1], des2);
thirdLevelq2.put(q2[0], des3);
thirdLevelq2.put(q2[1], des4);
thirdLevelq3.put(q3[0], des5);
data.add(thirdLevelq1);
data.add(thirdLevelq2);
data.add(thirdLevelq3);
expandableListView = (ExpandableListView) findViewById(R.id.expandible_listview);
//passing three level of information to constructor
ThreeLevelListAdapter threeLevelListAdapterAdapter = new ThreeLevelListAdapter(this, parent, secondLevel, data);
expandableListView.setAdapter(threeLevelListAdapterAdapter);
expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
int previousGroup = -1;
#Override
public void onGroupExpand(int groupPosition) {
if (groupPosition != previousGroup)
expandableListView.collapseGroup(previousGroup);
previousGroup = groupPosition;
}
});
}
}
Thanks in advance.
Edit: When I use Toast.makeText(getApplicationContext(), "The first child", Toast.LENGTH_LONG).show(); its crash logs says:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ExpandableListView.setOnChildClickListener(android.widget.ExpandableListView$OnChildClickListener)' on a null object reference
#Override
public void onFinalChildClick(int plpos, int slpos, int tlpos) {
String msg = "";
switch (tlpos) {
case 0:
msg = "Shakespear is a good poet";
break;
case 1:
msg = "Earth isn't flat";
break;
default:
msg = "Unknown";
}
Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
}
#Override
public void onFinalItemClick(String plItem, String slItem, String tlItem) {
String inMsg = plItem + ", " + slItem + ", " + tlItem;
String outMsg = "";
if (inMsg.equals("group 1, Child Level 1, A")){
outMsg = "Shakespear is a good poet";
} else if (inMsg.equals("group 1, Child Level 1, B")){
outMsg = "Earth isn't flat";
} else {
outMsg = "Unknown";
}
Toast.makeText(this, outMsg, Toast.LENGTH_SHORT).show();
}
Please set this listener expandableListView.setOnChildClickListener after the expandableListView is initialized, that is after setUpAdapter() in your case as expandableListView is still null when you are trying to set the listener because your initialization of this is afterwards.
That is the reason for NullPointerException. because expandableListView is null while setting the listener.
Cheers
I want to display a list of match objects (match = two users having liked each other) in a recycler view with the help of an adapter.
This is my activity which is meant to display those matches:
public class MatchesActivity extends AppCompatActivity {
// variables:
private RecyclerView mMatchesRecyclerView;
private RecyclerView.Adapter mMatchItemAdapter;
private RecyclerView.LayoutManager mMatchesLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_matches);
mMatchesRecyclerView = findViewById(R.id.matches_recyclerView);
mMatchesRecyclerView.setNestedScrollingEnabled(false);
mMatchesRecyclerView.setHasFixedSize(true);
// set layout manager & pass it to the recycler view:
mMatchesLayoutManager = new LinearLayoutManager(MatchesActivity.this);
mMatchesRecyclerView.setLayoutManager(mMatchesLayoutManager);
// set match adapter & pass it to the recycler view:
mMatchItemAdapter = new MatchItemAdapter(getMatchesList(), MatchesActivity.this);
mMatchesRecyclerView.setAdapter(mMatchItemAdapter);
// add test items to the recycler view:
Match testMatch = new Match("abcdefgh");
matchesList.add(testMatch);
mMatchItemAdapter.notifyDataSetChanged();
Log.d("MatchesActivity", "TEST LIST: " + matchesList.toString());
}
private ArrayList<Match> matchesList = new ArrayList<Match>();
private List<Match> getMatchesList() {
Log.d("MatchesActivity", "getMatchesList function: " + matchesList.toString());
return matchesList;
}
}
And this is my adapter which is supposed to inflate the relevant layout & populate it with relevant object data:
public class MatchItemAdapter extends RecyclerView.Adapter<MatchViewholder> {
private List<Match> mMatchesList;
private Context mViewContext;
public MatchItemAdapter(List<Match> matchesList, Context context) {
this.mMatchesList = matchesList;
this.mViewContext = context;
Log.d("MatchItemAdapter", "Constructor: " + mMatchesList.toString());
}
// inflate the layout:
#Override
public MatchViewholder onCreateViewHolder(ViewGroup parent, int viewType) {
View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_matches, null, false);
RecyclerView.LayoutParams lp = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
layoutView.setLayoutParams(lp);
MatchViewholder matchViewholder = new MatchViewholder(layoutView);
Log.d("MatchItemAdapter", "onCreateViewHolder: " + mMatchesList.toString());
return matchViewholder;
}
// populate each row within the layout:
#Override
public void onBindViewHolder(MatchViewholder holder, int position) {
Log.d("MatchItemAdapter", "onBindViewHolder: " + mMatchesList.toString());
holder.mMatchID.setText(mMatchesList.get(position).getMatchID());
}
#Override
public int getItemCount() {
return 0;
}
}
The Match class currently only takes matchID parameter which is string. An object is created with a default image and this matchID string.
At the moment, I have no real match objects from database ready, so I wanted to check that the recycler view along with adapter are working as expected before i move on to that later.
However, when I go to Matches Activity, it is empty, showing nothing at all. As you can see from the MatchesActivity onCreate method, I created a test Match object with matchID = "abcdefgh" and then added that to the matchesList. So I am expecting the "abcdefgh" text to be passed to the adapter and to be shown in the MatchesActivity.
My log statements indicate that the Match object has been created and added to the list successfully, however, getMatchesList() function returns an empty list which is then used in the Adapter constructor too, (I think this is) causing Activity not show anything.
I am relatively new to Android and Java development, especially recycler view and adapters, but from what I gathered it seems to be as if the
mMatchItemAdapter.notifyDataSetChanged();
is not working properly as everything seems to be fine up until that point. Any help would be appreciated!
You're returning 0. What you should do instead is return the length of the mMatchesList list.
#Override
public int getItemCount() {
return mMatchesList.size();
}
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.
I have been reading different posts on here about baseadapters and trying to learn so that I can fix my issue but I haven't been able to resolve it. On my BaseAdapter I have a String called post that is used in a column in the listview. If the post is longer than 13 characters then it is shortened automatically when the user Clicks on the shortened post then it displays it's full length,however the issue is that once you scroll down the listview and come back up to that same post it's still shortened even though the user clicked before to show the full post. I think this is an issue of the Listview or Baseadapter recycling or cache mechanism is there anyway I can fix this? This image will clear things up .. This post is more than 13 characters so it shows the shortened version
if a user wants to read it in full then they will click on the Read More which will then show all of the content which looks like this
and when the user scrolls down or up that same long post will return to this without the user clicking it again, which I want to avoid
I know that the Listview recycles but how can I update it? This is my code below
public class LocalFeed_CustomView extends BaseAdapter {
JSONObject names;
Context ctx;
Activity m;
// More is the default value
String result="More";
#Override
public int getCount() {
try {
JSONArray jaLocalstreams = names.getJSONArray("localstreams");
return jaLocalstreams.length();
} catch (Exception e) {
Toast.makeText(ctx, "Error: Please try again", Toast.LENGTH_LONG).show();
return names.length();
}
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View row=convertView;
MyViewHolder holder=null;
try {
if (row == null) {
LayoutInflater li = (LayoutInflater) m.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = li.inflate(R.layout.customadapter, null);
holder = new MyViewHolder(row);
row.setTag(holder);
} else {
holder = (MyViewHolder) row.getTag();
}
final MyViewHolder finalHolder1=holder;
// Json data has been read
JSONArray jaLocalstreams = names.getJSONArray("localstreams");
final JSONObject jsonObject = jaLocalstreams.getJSONObject(position);
// if post length is more than 14 then shorten it
if (jsonObject.getString("post").length() > 14) {
holder.post.setText(jsonObject.getString("post").substring(0, 13) + "...Read More");
holder.post.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
try {
// if Result is More then show full post
if (result.equals("More")) {
finalHolder1.post.setText(jsonObject.getString("post") + "... Read Less");
result = "Less";
}
else
{
//Result is Less so shorten it again
finalHolder1.post.setText(jsonObject.getString("post").substring(0, 13) + "... Read More");
result = "More";
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
} else{
// This Post is already less than 14 characters so no Onclick here
holder.post.setText(jsonObject.getString("post"));
}
return row;
} catch (Exception e) {
e.printStackTrace();
}
return row;
}
class MyViewHolder{
TextView post;
MyViewHolder(View v)
{
post = (TextView)v.findViewById(R.id.post);
}
}
}
The adapter represents the model of the list at any given moment in time.
What this means to you is that if a user clicks a TextView to expand it with the idea that the view is going to stay expanded, then that expanded TextView is state information that will have to be captured in the adapter.
Adapters should always be thought of in two phases:
Event (like onClick()) will update state in the adapter and call notifyDataSetChanged().
getView() uses the current state to create the view.
So let's say in the adapter constructor we create an array of flags
boolean expanded[] = new boolean[size];
where size is the length of your list.
Then you can do this:
// use the current state to create the view
String text;
if (expanded[position]) {
text = jsonObject.getString("post") + "... Read Less";
} else {
text = jsonObject.getString("post").substring(0, 13) + "...Read More";
}
holder.post.setText(text);
holder.post.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// update the current state and request list refresh
expanded[position] = ! expanded[position]; // toggle
notifyDataSetChanged();
}
});
This code doesn't do exactly what yours does, I just wanted to give you the basic idea.