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@@ -0,0 +1,69 @@
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+package eu.kanade.mangafeed.widget;
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+
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+import android.widget.AbsListView;
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+
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+public abstract class EndlessScrollListener implements AbsListView.OnScrollListener {
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+ // The minimum amount of items to have below your current scroll position
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+ // before loading more.
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+ private int visibleThreshold = 5;
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+ // The current offset index of data you have loaded
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+ private int currentPage = 0;
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+ // The total number of items in the dataset after the last load
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+ private int previousTotalItemCount = 0;
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+ // True if we are still waiting for the last set of data to load.
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+ private boolean loading = true;
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+ // Sets the starting page index
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+ private int startingPageIndex = 0;
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+
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+ public EndlessScrollListener() {
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+ }
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+
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+ public EndlessScrollListener(int visibleThreshold) {
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+ this.visibleThreshold = visibleThreshold;
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+ }
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+
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+ public EndlessScrollListener(int visibleThreshold, int startPage) {
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+ this.visibleThreshold = visibleThreshold;
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+ this.startingPageIndex = startPage;
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+ this.currentPage = startPage;
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+ }
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+
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+ // This happens many times a second during a scroll, so be wary of the code you place here.
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+ // We are given a few useful parameters to help us work out if we need to load some more data,
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+ // but first we check if we are waiting for the previous load to finish.
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+ @Override
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+ public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
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+ {
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+ // If the total item count is zero and the previous isn't, assume the
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+ // list is invalidated and should be reset back to initial state
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+ if (totalItemCount < previousTotalItemCount) {
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+ this.currentPage = this.startingPageIndex;
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+ this.previousTotalItemCount = totalItemCount;
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+ if (totalItemCount == 0) { this.loading = true; }
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+ }
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+ // If it’s still loading, we check to see if the dataset count has
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+ // changed, if so we conclude it has finished loading and update the current page
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+ // number and total item count.
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+ if (loading && (totalItemCount > previousTotalItemCount)) {
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+ loading = false;
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+ previousTotalItemCount = totalItemCount;
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+ currentPage++;
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+ }
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+
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+ // If it isn’t currently loading, we check to see if we have breached
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+ // the visibleThreshold and need to reload more data.
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+ // If we do need to reload some more data, we execute onLoadMore to fetch the data.
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+ if (!loading && (totalItemCount - visibleItemCount)<=(firstVisibleItem + visibleThreshold)) {
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+ loading = onLoadMore(currentPage + 1, totalItemCount);
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+ }
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+ }
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+
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+ // Defines the process for actually loading more data based on page
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+ // Returns true if more data is being loaded; returns false if there is no more data to load.
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+ public abstract boolean onLoadMore(int page, int totalItemsCount);
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+
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+ @Override
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+ public void onScrollStateChanged(AbsListView view, int scrollState) {
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+ // Don't take any action on changed
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+ }
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+}
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