[英]Load more data into ListView - Android
我實現了一個listview,其中通過asynctask加載了數據,要加載更多數據,我使用了此處找到的代碼(完全復制粘貼)
主要活動
class load_data extends AsyncTask<Integer, Void, Void>{
// This asynctask takes in a page number as argument and depending on that page number
// data is loaded and stored in various String[] arrays and their length is extended as new items are loaded
protected void onPostExecute(Void result) {
if(adapter == null){
adapter = new Listadapter(Main.this,String[],String[],String[]);
list.setAdapter(adapter);
}
else if(adapter != null){
adapter.notifyDataSetChanged();
}
}
}
此任務稱為new load_data().execute(1);
在這段代碼之后,我從上面的鏈接中加載了更多數據片段,一切正常,沒有語法錯誤,而且在我的情況下,重新達到給定的閾值(20)后,數據也加載了,但是未顯示新數據。 如何通知適配器已添加更多數據或更改了數據,謝謝!
編輯:LOADMORE CLASS
class EndlessScrollListener implements OnScrollListener {
private int visibleThreshold = 5;
private int currentPage = 1;
private int previousTotal = 0;
private boolean loading = true;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
currentPage++;
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// I load the next page of gigs using a background task,
// but you can call any function here.
new load_data().execute(currentPage);
adapter.notifyDataSetChanged();
loading = true;
}
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
}
list.setOnScrollListener(new EndlessScrollListener(20)); // 20 being the threshold
最后! 對於那些遇到相同問題的人,我有解決方案。
我注意到那個adapter.notifyDataSetChanged();
如果您使用String []數組存儲顯示在列表視圖行中的數據,則無法正常工作。
相反,如果您使用List<String> list = new ArrayList<String>();
並在listview中存儲數據將使用新數據進行更新:)
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