I have an API response that I need to show on my listView. At the beginning It starts off with 15 items, and I want to add more as the user scrolls down and reaches the end of the list. What would be the best strategy to page through the API automatically with Retrofit, so that all available data is downloaded by default? Unfortunately I am a beginner and this is as far as I can get. Please help! Any help would be appreciated.
These are the parameters from the response I need to use:
"total": 181,
"per_page": "15",
"current_page": 1,
"last_page": 13,
"next_page_url": "URL",
"prev_page_url": null,
"from": 1,
"to": 15,MainActivity:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://nmc.no-ip.org:8888/")
.addConverterFactory(GsonConverterFactory.create())
.build();
StreamingOfferService service = retrofit.create(StreamingOfferService.class);
Call<ResponseResult> response = service.getStreamingOffers();
response.enqueue(new Callback<ResponseResult>() {
@Override
public void onResponse(Call<ResponseResult> result, Response<ResponseResult> response) {
createList(response);
}
@Override
public void onFailure(Call<ResponseResult> result, Throwable t) {
}
});
}
public void createList(final Response<ResponseResult> response)
{
final ListView listview = (ListView) findViewById(R.id.listview);
final StreamingAdapter adapter = new StreamingAdapter(this,R.layout.listofusers,response);
listview.setAdapter(adapter);
listview.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
ResponseResult r = new ResponseResult();
int currentPageNumber = r.getCurrentPage();
boolean loading = true;
String next_page_url = r.getNextPageUrl();
if (listview.getLastVisiblePosition() == listview.getAdapter().getCount() - 1
&& listview.getChildAt(listview.getChildCount() - 1).getBottom() <= listview.getHeight()) {
// r.getNextPageUrl();
// currentPageNumber++;
loading = true;
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(r.getNextPageUrl()) // this is not working
.addConverterFactory(GsonConverterFactory.create())
.build();
StreamingOfferService service = retrofit.create(StreamingOfferService.class);
Call<ResponseResult> response = service.getStreamingOffers();
response.enqueue(new Callback<ResponseResult>() {
@Override
public void onResponse(Call<ResponseResult> result, Response<ResponseResult> response) {
// StreamingAdapter adapter = new StreamingAdapter(this,R.layout.listofusers, response);.
}
@Override
public void onFailure(Call<ResponseResult> result, Throwable t) {
}
});
}}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}The Adapter:
public class StreamingAdapter extends BaseAdapter {
private Context context;
private int resource;
private LayoutInflater inflater;
private List<StreamingOffer> streamingOfferList;
public StreamingAdapter(Context context, int resource, Response<ResponseResult> response) {
this.context=context;
this.resource=resource;
this.inflater=LayoutInflater.from(context);
streamingOfferList = response.body().getData();
}
void addToList(List<ResponseResult> updatedlist)
{
this.streamingOfferList.addAll(updatedlist); // how do I add the new response here
this.notifyDataSetChanged();
}
public class Holder extends User {
private TextView full_name;
private TextView location;
private TextView price;
private TextView currency_symbol;
private TextView total_streamed;
private ImageView offer;
private ImageView profile;
private ImageView iconUser;
private ImageView iconStar;
private ImageView iconStar1;
private ImageView iconStar2;
private ImageView iconStar3;
private ImageView iconStar4;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder = new Holder();
View itemView = convertView;
StreamingOffer streamingOffer = getItem(position);
User u = streamingOffer.getUser();
if(itemView==null) {
itemView = inflater.inflate(resource, parent, false);
holder.full_name = (TextView) itemView.findViewById(R.id.full_name);
holder.full_name.setText(u.getFullName());
holder.location = (TextView) itemView.findViewById(R.id.location);
holder.location.setText(streamingOffer.getLocation());
holder.price = (TextView) itemView.findViewById(R.id.price);
holder.currency_symbol = (TextView) itemView.findViewById(R.id.currency_symbol);
if(streamingOffer.getIs_free()==0)
{
holder.price.setText(streamingOffer.getPrice());
holder.currency_symbol.setText(streamingOffer.getCurrencySymbol());
}
else
holder.price.setText("FREE");
holder.total_streamed = (TextView) itemView.findViewById(R.id.total_streamed);
holder.total_streamed.setText(u.getTotalStreamed());
holder.offer = (ImageView) itemView.findViewById(R.id.offer);
holder.profile = (ImageView) itemView.findViewById(R.id.profile);
holder.iconUser = (ImageView) itemView.findViewById(R.id.iconUser);
holder.iconStar = (ImageView) itemView.findViewById(R.id.iconStar);
holder.iconStar1 = (ImageView) itemView.findViewById(R.id.iconStar1);
holder.iconStar2 = (ImageView) itemView.findViewById(R.id.iconStar2);
holder.iconStar3 = (ImageView) itemView.findViewById(R.id.iconStar3);
holder.iconStar4 = (ImageView) itemView.findViewById(R.id.iconStar4);
Images im = new Images();
final GsonBuilder builder = new GsonBuilder();
final Gson gson = builder.create();
String jsonRepresentation = gson.toJson(im);
if(jsonRepresentation.contains("75x75")){
Picasso.with(context).load(im.getImage_75x75()).into(holder.profile);
}
//Picasso.with(context).load(jsonRepresentation).into(holder.offer);
Picasso.with(context).load(im.getImage_154x154()).into(holder.profile);
Picasso.with(context).load(im.getImage_154x154()).into(holder.offer);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.half_red_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar4);
// Picasso.with(context)
// .load("http://nmc.no-ip.org:8888/assets/images/offer-2.png").into(holder.offer);
// Picasso.with(context)
// .load("http://nmc.no-ip.org:8888/assets/images/profile-1.png").into(holder.profile);
if(u.getIs_online()==1) {
Picasso.with(context)
.load(R.drawable.icon_user_online).into(holder.iconUser);
}
else
Picasso.with(context)
.load(R.drawable.icon_user_offline).into(holder.iconUser);}
if(u.getRating()!=null) {
if (u.getRating() == "1.0" && u.getRating() == "1.5") {
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar4);
}
if (u.getRating() == "2.0" && u.getRating() == "2.5") {
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar4);
}
if (u.getRating() == "3.0" && u.getRating() == "3.5") {
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar4);
}
if (u.getRating() == "4.0" && u.getRating() == "4.5") {
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_black_star).into(holder.iconStar4);
}
if (u.getRating() == "5.0") {
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar1);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar2);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar3);
Picasso.with(context)
.load(R.drawable.icon_red_star).into(holder.iconStar4);
}
}
itemView.setTag(holder);
return itemView;
}
@Override
public int getCount() {
return streamingOfferList.size();
}
@Override
public StreamingOffer getItem(int position) {
return streamingOfferList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
}