Android：保存ListView项目并加载/添加更多内容
[英]Android: Saving ListView items and load/add more
问题描述
I'm trying to load some number of more items in my ListView when I scroll to the bottom and just ADD them to the current ones. 
当我滚动到底部并将它们添加到当前项时，我试图在ListView中加载更多数量的项。 It works well, but recently I found out that it loads ALL objects again, only with more items. 它运作良好，但最近我发现它再次加载所有对象，但只包含更多项。 I'm using Parse.com. 我正在使用Parse.com。 I discovered, that Parse.com provides their own custom ParseQueryAdapter, which contains getNextPageView() method. 我发现，Parse.com提供了自己的自定义ParseQueryAdapter，其中包含getNextPageView（）方法。 It loads move items, but only when the user clicks on the button below. 它加载移动项目，但仅当用户单击下面的按钮时才加载。 I also tried .setSkip(someNumber) method but it only erases/hides someNumber of items in the top. 我也尝试了.setSkip(someNumber)方法，但是它只擦除/隐藏顶部的someNumber项。 So I still want to use OnScrollListener and really load-more and not load-again+more. 因此，我仍然想使用OnScrollListener并真正加载更多而不是再次加载更多。
Do you have any idea, how to do it? 你有什么想法，怎么做？
check my codes: 检查我的代码：
public void updateData() {
mListView = (ListView)getView().findViewById(R.id.animal_list);
final ParseQuery<Animal> query = ParseQuery.getQuery(Animal.class);
query.setCachePolicy(CachePolicy.NETWORK_ONLY);
query.orderByAscending("animal");
query.setLimit(mListView.getCount() + 5);
query.findInBackground(new FindCallback<Animal>() {
@Override
public void done(List<Animal> animals, ParseException error) {
if(animals != null){
mAdapter.clear();
mProgressBar = (ProgressBar) getView().findViewById (R.id.loading_animals);
mProgressBar.setVisibility(View.INVISIBLE);
RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);
footie.setVisibility(View.VISIBLE);
for (int i = 0; i < animals.size(); i++) {
mAdapter.add(animals.get(i));
ArrayList<Animal> animal = new ArrayList<Animal>();
animal.add(animals.get(i));
}
}
}
}); }
private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute(); }
@Override
protected Void doInBackground(Void... params) {
return null;
}
@Override
protected void onPostExecute(Void result) {
mListView = (ListView) getView().findViewById(R.id.animal_list);
mEditText = (EditText) getView().findViewById(R.id.search_animal);
mAdapter = new AnimalAdapter(getActivity(), new ArrayList<Animal>());
mListView.setVisibility(View.VISIBLE);
mListView.setTextFilterEnabled(true);
mListView.setAdapter(mAdapter);
mListView.setOnScrollListener(new OnScrollListener() {
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
int totalItemCount) {
final int lastItem = firstVisibleItem + visibleItemCount;
if(lastItem == totalItemCount) {
if (mListView.getCount() > 20) {
RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);
mListView.removeFooterView(footie);
}
else{
updateData();
}
}
}
}
Thanks in advance 提前致谢
1 个解决方案
解决方案1
1 已采纳 2014-01-27 04:05:43
Try to clear Adapter before setting it to ListView like as follows: 尝试清除Adapter然后将其设置为ListView ，如下所示：
public void updateData() {
mListView = (ListView)getView().findViewById(R.id.animal_list);
final ParseQuery<Animal> query = ParseQuery.getQuery(Animal.class);
query.setCachePolicy(CachePolicy.NETWORK_ONLY);
query.orderByAscending("animal");
query.setLimit(mListView.getCount() + 5);
query.findInBackground(new FindCallback<Animal>() {
@Override
public void done(List<Animal> animals, ParseException error) {
if(animals != null){
mAdapter.clear();
mProgressBar = (ProgressBar) getView().findViewById (R.id.loading_animals);
mProgressBar.setVisibility(View.INVISIBLE);
RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);
footie.setVisibility(View.VISIBLE);
mAdapter.clear();///////HERE
for (int i = 0; i < animals.size(); i++) {
mAdapter.add(animals.get(i));
ArrayList<Animal> animal = new ArrayList<Animal>();
animal.add(animals.get(i));
}
}
}
}); }
private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute(); }
@Override
protected Void doInBackground(Void... params) {
return null;
}
@Override
protected void onPostExecute(Void result) {
mListView = (ListView) getView().findViewById(R.id.animal_list);
mEditText = (EditText) getView().findViewById(R.id.search_animal);
mAdapter = new AnimalAdapter(getActivity(), new ArrayList<Animal>());
mListView.setVisibility(View.VISIBLE);
mListView.setTextFilterEnabled(true);
mListView.setAdapter(mAdapter);
mListView.setOnScrollListener(new OnScrollListener() {
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
int totalItemCount) {
final int lastItem = firstVisibleItem + visibleItemCount;
if(lastItem == totalItemCount) {
if (mListView.getCount() > 20) {
RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);
mListView.removeFooterView(footie);
}
else{
updateData();
}
}
}
}
You are only adding items without wiping previous data. 您仅添加项目而不清除先前的数据。
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