無限スクロールListView
と Koush-ion ライブラリに問題があります。問題は、エンドレス スクロールが最初のイオン リクエストなしでは機能しないことです。私のコード:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_news);
newsList = new ArrayList<>();
initViews();
setAdapter();
ionGetNews(1); //if comment this line listView will be empty.
listViewNews.setOnScrollListener(new EndlessScrollListener() {
@Override
public void onLoadMore(int page, int totalItemsCount) {
Log.d("Scroll_page", page + "");
//ionGetNews(page);
Toast.makeText(NewsActivity.this, page + "", Toast.LENGTH_SHORT).show();
}
});
}
private void initViews() {
listViewNews = (ListView) findViewById(R.id.listViewNews);
}
private void setAdapter() {
adapterNews = new AdapterNews(NewsActivity.this, newsList);
listViewNews.setAdapter(adapterNews);
}
private void ionGetNews(int page) {
JsonObject jo = new JsonObject();
jo.addProperty("page", page);
jo.addProperty("type", 0);
jo.addProperty("favourite_shop", 0);
Log.d("Json_info", jo.toString());
Ion.with(NewsActivity.this)
.load(Constants.POST, Constants.BASE_URL + Constants.NEWS)
.setJsonObjectBody(jo)
.asJsonArray()
.setCallback(new FutureCallback<JsonArray>() {
@Override
public void onCompleted(Exception e, JsonArray result) {
if (e != null) {
}
if (result != null) {
newsParseJson(result);
} else {
}
}
});
}
private void newsParseJson(JsonArray array) {
Gson gson = new Gson();
Type listType = new TypeToken<List<News>>() {
}.getType();
List<News> newses = (List<News>) gson.fromJson(array, listType);
newsList.addAll(newses);
adapterNews.notifyDataSetChanged();
listViewNews.setVisibility(View.VISIBLE);
Log.d("NewsList", newses.toString());
}
EndlessScrollListener クラス:
public abstract class EndlessScrollListener implements AbsListView.OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 15;
// The current offset index of data you have loaded
private int currentPage = 1;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
public EndlessScrollListener(int visibleThreshold, int startPage) {
this.visibleThreshold = visibleThreshold;
this.startingPageIndex = startPage;
this.currentPage = startPage;
}
// This happens many times a second during a scroll, so be wary of the code you place here.
// We are given a few useful parameters to help us work out if we need to load some more data,
// but first we check if we are waiting for the previous load to finish.
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (!loading && (totalItemCount < previousTotalItemCount)) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) { this.loading = true; }
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount)) {
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (totalItemCount - visibleItemCount)<=(firstVisibleItem + visibleThreshold)) {
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// Don't take any action on changed
}
}
私が間違っていることは何ですか?この問題を解決するには?