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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 background colour to specific viewholder items in a RecycleView?

I am trying to change background color in specific item(s) in a RecycleView.
Because I need to set text too, I have the following code that works fine:
protected void populateViewHolder(RankingViewHolder viewHolder, final Ranking model, int position)
{
final Context mContext = getActivity().getApplicationContext();
viewHolder.txt_name.setText(model.getUserName());
viewHolder.txt_score.setText(String.valueOf(model.getScore()));
viewHolder.txt_class.setText(model.getUser_class());
Picasso.with(mContext).load(model.getAvatarUrl()).error(R.drawable.ic_people_black_24dp).into(viewHolder.personPhoto);
int totalRanking = adapter.getItemCount();
int realRank = totalRanking - viewHolder.getAdapterPosition();
viewHolder.ranknumber.setText("# "+String.valueOf(realRank));
}
This works as I want and realRanktakes the correct values, and the viewHolder.ranknumber.setText("# "+String.valueOf(realRank));
Sets the right text with no problem.
Now I am trying (as I got a number/text result correct, to make an if statement like this:
if(adapter.getItemCount() -viewHolder.getAdapterPosition() == 0)
{
viewHolder.itemView.setBackgroundColor(Color.GREEN);
}
if(adapter.getItemCount() -viewHolder.getAdapterPosition() == 1)
{
viewHolder.itemView.setBackgroundColor(Color.YELLOW);
}
if(adapter.getItemCount() -viewHolder.getAdapterPosition() == 2)
{
viewHolder.itemView.setBackgroundColor(Color.BLUE);
}
(I tried with String.valueOf(realRank)equality, with realRankequality too)
In all cases I have the same result. The color changes as its should at positions 1,2,3 BUT it changes at positions 7,8,9 and 14,15,16 and 21,22,23 etc.
What am I missing here?
public class RankingViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
{
private ItemClickListener itemClickListener;
public TextView txt_name, txt_score, txt_class, ranknumber;
public ImageView personPhoto;
public RankingViewHolder(View itemView)
{
super(itemView);
txt_name = itemView.findViewById(R.id.txt_name);
txt_score = itemView.findViewById(R.id.txt_score);
personPhoto = itemView.findViewById(R.id.person_photo);
txt_class = itemView.findViewById(R.id.txt_class);
ranknumber = itemView.findViewById(R.id.ranknumber);
itemView.setOnClickListener(this);
}
public void setItemClickListener(ItemClickListener itemClickListener) {
this.itemClickListener = itemClickListener;
}
#Override
public void onClick(View view) {
itemClickListener.onClick(view , getAdapterPosition(),false);
}
}
The adapter:
adapter = new FirebaseRecyclerAdapter<Ranking, RankingViewHolder>(
Ranking.class,
R.layout.layout_ranking,
RankingViewHolder.class,
rankingTbl.orderByChild("score").limitToFirst(100)
)
This line of code int realRank = totalRanking - viewHolder.getAdapterPosition();gives a number (1,2,3,4,5,6 etc.) Why i cannot use this number to check equality?
Notice
Keeping this code for NOT working solution, just for future reference:
if(position == 0){
viewHolder.itemView.setBackgroundColor(Color.GREEN);
}
else if(position == 1){
viewHolder.itemView.setBackgroundColor(Color.YELLOW);
}
else if(position == 2){
viewHolder.itemView.setBackgroundColor(Color.BLUE);
}
else{
viewHolder.itemView.setBackgroundColor(Color.WHITE);
}
This changes the color BUT not for only 3 first items. As you scroll down, changes the color for every 3 first viewable items like before, meaning 1,2,3, 7,8,9, etc.
Update:
I dont use a custom adapter, i use FirebaseRecyclerAdapter.
Thanks to #Muhammad Haroon comment i checked that has getItemViewType. So now i m trying with it like
position =adapter.getItemViewType( 0);
if(position == 0){
viewHolder.itemView.setBackgroundColor(Color.GREEN);
}
Not working for now, but i think its the correct direction...
Update 2
With position its not possible as RecycleView recycles the views so i have the same result. The working code is
if (linearLayoutManager.findFirstVisibleItemPosition() > 0) {
viewHolder.itemView.setBackgroundResource(R.drawable.blackframe);
}
else{
viewHolder.itemView.setBackgroundResource(R.drawable.goldframe);
}
Works fine except that after scrolling loosing the change of background.
So as we want and need the perfection, any idea for keeping even after scroll?

hi try add this in your Adapater it may solve your problem.
#Override
public int getItemViewType(int position) {
return position;
}

Please give this a try
override in your custom adapter
#Override
public long getItemId(int position) {
return position;
}
and in in your adapter object:
myAdapter.setHasStableIds(true);

In populateViewHolder add these line of code
if(position == 0){
viewHolder.itemView.setBackgroundColor(Color.GREEN);
}
else if(position == 1){
viewHolder.itemView.setBackgroundColor(Color.YELLOW);
}
else if(position == 2){
viewHolder.itemView.setBackgroundColor(Color.BLUE);
}
else{
viewHolder.itemView.setBackgroundColor(Color.WHITE);
}
position is a parameter in populateViewHolder.

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.

Android Listview in Baseadapter how can I save changes to the list

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.

Passing values to a function in Java

I am building an android app for work using android studio. I have a list of witnesses stored as sharedpreference, when the uses clicks to amend these witnesses are split up and listed the user can then click the witness they want to amend, well that's the plan, I just cant seem pass the witness listed number (basically the number used in the loop) to another function that will load the witnesses information into a form to be amended. Below is my code:
String s= WitnessDetails;
String[] array = s.split("$_$(?=[0-9])");
LinearLayout parentLayout = (LinearLayout)findViewById(R.id.LinearLayout);
// Layout inflater
LayoutInflater layoutInflater = getLayoutInflater();
View view;
for(String str : array)
{
countWitness++;
String WitnessName= str;
view = layoutInflater.inflate(R.layout.witnesses_activity, parentLayout, false);
// In order to get the view we have to use the new view with text_layout in it
TextView textView = (TextView)view.findViewById(R.id.Witnesses_details);
textView.setText("Witness 1: " + countWitness + "\n" + WitnessName+"\n Edit");
// Add the text view to the parent layout
parentLayout.addView(textView);
textView.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Amendwitness(countWitness);
}
});
}
public void Amendwitness(witnessNum){
}

You are using countWitness inside an inner anonymous class, so either
countWitness should be final
or
countWitness should be class field
otherwise compiler will show error. Since countWitness is incremented inside for-loop, it cannot be declared final, so the only solution left is to make it as class-field
OR
you can use the setTag(Object) function
for(String str : array)
{
countWitness++;
String WitnessName= str;
view = layoutInflater.inflate(R.layout.witnesses_activity, parentLayout, false);
TextView textView = (TextView)view.findViewById(R.id.Witnesses_details);
textView.setText("Witness 1: " + countWitness + "\n" + WitnessName+"\n Edit");
textView.setTag(countWitness); // set the countWitness as tag object
parentLayout.addView(textView);
textView.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Amendwitness((Integer)arg0.getTag());
}
});
}

Here are two possibilities:
Add a custom MyClickListener class:
public class MyClickListener implements View.OnClickListener {
private int mIndex;
public MyClickListener(int index) {
mIndex = index;
}
#Override
public void onClick(View v) {
Amendwitness(index);
}
}
Add your OnClickListeners like this:
textView.setOnClickListener(new MyClickListener(countWitness));
Use the tag of the View:
textView.setTag(countWitness);
textView.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Amendwitness(v.getTag());
}
});