ListFragment载入更多的滚动结束 [英] ListFragment Load more on scroll end
本文介绍了ListFragment载入更多的滚动结束的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有我的ListFragment，想知道什么，当我到达底部加载的最佳方式列表中更多的内容，我认为我需要实现一个滚动监听器，但我是在何时何地有一点点困惑调用执行，如果有人能提供一些线索，这将是多少AP preciated，我知道我的codeS稍微有点乱，现在也因为我只是测试了这一点，所以道歉的。
I have for my ListFragment and was wondering what the best way to load more content within the list when I reach the bottom, I believe I need to implement a Scroll Listener but I was a little confused on where and when to have the call performed, if someone can shed some light that would be much appreciated, I know my codes a tad bit messy right now too since I am just testing this out, so apologies for that.
code： TestListFragment
package com.fragments;
public class TestListFragment extends ListFragment
implements
android.support.v4.app.LoaderManager.LoaderCallbacks<List<TestItemModel>> {
TestCustomArrayAdapter _adapter;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
System.out.println("TestListFragment.onActivityCreated");
// Initially there is no data
setEmptyText("Refresh: No Data Here");
// Create an empty adapter we will use to display the loaded data.
_adapter = new TestCustomArrayAdapter(getActivity());
setListAdapter(_adapter);
// Start out with a progress indicator.
setListShown(false);
// Prepare the loader. Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Insert desired behavior here.
Log.i("TestListFragment", "Item clicked: " + id);
TestItemModel ti = this._adapter.getItem(position);
System.out.println(ti.getId());
}
@Override
public Loader<List<TestItemModel>> onCreateLoader(int arg0, Bundle arg1) {
System.out.println("TestListFragment.onCreateLoader");
return new TestListLoaderAsync(getActivity());
}
@Override
public void onLoadFinished(Loader<List<TestItemModel>> arg0,
List<TestItemModel> data) {
_adapter.setData(data);
System.out.println("TestListFragment.onLoadFinished");
// The list should now be shown.
if (isResumed()) {
setListShown(true);
} else {
setListShownNoAnimation(true);
}
}
@Override
public void onLoaderReset(Loader<List<TestItemModel>> arg0) {
_adapter.setData(null);
}
}
TestCustomArrayAdapter
package com.adapters;
public class TestCustomArrayAdapter extends ArrayAdapter<TestItemModel> {
private final LayoutInflater _inflater;
public OnItemClickListener _ol;
public ImageLoader _imageLoader;
public TestCustomArrayAdapter(Context context) {
super(context, R.layout.test_list_fragment);
_inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// Load up Image Loader
_imageLoader = new ImageLoader(context);
}
public void setData(List<TestItemModel> data) {
clear();
if (data != null) {
for (TestItemModel appEntry : data) {
add(appEntry);
}
}
}
/**
* Populate new items in the list.
*/
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// create viewHolder
View view;
// Check Views
if (convertView == null) {
view = _inflater.inflate(R.layout.test_single_item, parent, false);
} else {
view = convertView;
}
// Create Items
TestItemModel item = getItem(position);
TextView itemLabel = (TextView) view.findViewById(R.id.item_label);
TextView itemId = (TextView) view.findViewById(R.id.item_id);
// Create ImageViews
ImageView image = (ImageView) view.findViewById(R.id.image_id);
// Create Buttons
Button btn1 = (Button) view.findViewById(R.id.button_id_1);
Button btn2 = (Button) view.findViewById(R.id.button_id_2);
Button btn3 = (Button) view.findViewById(R.id.button_id_3);
// Create Resources
Resources resources = this.getContext().getResources();
// Create Listeners
_ol = new OnItemClickListener(position, item);
// Setup TextViews
itemLabel.setText(item.getName());
itemId.setText(item.getName());
// Setup Images
_imageLoader.DisplayImage(item.getBm(), image);
// Setup Buttons
btn1.setOnClickListener(_ol);
btn1.setTag(1);
btn2.setOnClickListener(_ol);
btn2.setTag(2);
btn3.setOnClickListener(_ol);
btn3.setTag(3);
return view;
}
private class OnItemClickListener implements OnClickListener {
private int _position;
private TestItemModel _testItem;
public OnItemClickListener(int position, TestItemModel ti) {
_position = position;
_testItem = ti;
}
// TODO
// provide functionality for which button was clicked then pass the item
// to which it was clicked in.
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button_id_1:
// btn1 clicked
Toast.makeText(getContext(),
" Button1 clicked at positon" + v.getTag(),
Toast.LENGTH_SHORT).show();
break;
case R.id.button_id_2:
// btn2 clicked
Toast.makeText(getContext(),
" Button2 clicked at positon" + v.getTag(),
Toast.LENGTH_SHORT).show();
break;
case R.id.button_id_3:
Toast.makeText(getContext(),
" Button3 clicked at positon" + v.getTag(),
Toast.LENGTH_SHORT).show();
// btn 3 clciked
break;
}
// the view is the button, so you get get the tag it has set with
// v.getTag() to know what button is pressed.
Log.v("YOOO",
"Button Click at position " + _position + " " + v.getTag()
+ " Item ID = " + _testItem.getId());
}
}
}
TestListLoaderAsync
包com.tasks;
package com.tasks;
公共类TestListLoaderAsync扩展AsyncTaskLoader> {
public class TestListLoaderAsync extends AsyncTaskLoader> {
private List<TestItemModel> _models;
// Test URLS
private final String[] URLS = {
"http://www.pressurewasherparts.com.au/upimages/image/Water_Broom/Water%20Broom%203%20Noz%20upright.jpg",
"http://www.pressurewasherparts.com.au/upimages/image/Water_Broom/Water%20Broom%203%20Noz%20upright.jpg",
"http://lh3.ggpht.com/_GEnSvSHk4iE/TDSfmyCfn0I/AAAAAAAAF8Y/cqmhEoxbwys/s144-c/_MG_3675.jpg",
"http://lh6.ggpht.com/_Nsxc889y6hY/TBp7jfx-cgI/AAAAAAAAHAg/Rr7jX44r2Gc/s144-c/IMGP9775a.jpg",
"http://lh3.ggpht.com/_lLj6go_T1CQ/TCD8PW09KBI/AAAAAAAAQdc/AqmOJ7eg5ig/s144-c/Juvenile%20Gannet%20despute.jpg",
"http://lh6.ggpht.com/_ZN5zQnkI67I/TCFFZaJHDnI/AAAAAAAABVk/YoUbDQHJRdo/s144-c/P9250508.JPG",
"http://lh4.ggpht.com/_XjNwVI0kmW8/TCOwNtzGheI/AAAAAAAAC84/SxFJhG7Scgo/s144-c/0014.jpg",
"http://lh6.ggpht.com/_lnDTHoDrJ_Y/TBvKsJ9qHtI/AAAAAAAAG6g/Zll2zGvrm9c/s144-c/000007.JPG",
"http://lh6.ggpht.com/_qvCl2efjxy0/TCIVI-TkuGI/AAAAAAAAOUY/vbk9MURsv48/s144-c/DSC_0844.JPG",
"http://lh4.ggpht.com/_TPlturzdSE8/TBv4ugH60PI/AAAAAAAAMsI/p2pqG85Ghhs/s144-c/_MG_3963.jpg",
"http://lh4.ggpht.com/_4f1e_yo-zMQ/TCe5h9yN-TI/AAAAAAAAXqs/8X2fIjtKjmw/s144-c/IMG_1786.JPG",
"http://lh6.ggpht.com/_iFt5VZDjxkY/TB9rQyWnJ4I/AAAAAAAADpU/lP2iStizJz0/s144-c/DSCF1014.JPG",
"http://lh5.ggpht.com/_hepKlJWopDg/TB-_WXikaYI/AAAAAAAAElI/715k4NvBM4w/s144-c/IMG_0075.JPG",
"http://lh6.ggpht.com/_OfRSx6nn68g/TCzsQic_z3I/AAAAAAABOOI/5G4Kwzb2qhk/s144-c/EASTER%20ISLAND_Hanga%20Roa_31.5.08_46.JPG",
"http://lh6.ggpht.com/_ZGv_0FWPbTE/TB-_GLhqYBI/AAAAAAABVxs/cVEvQzt0ke4/s144-c/IMG_1288_hf.jpg",
"http://lh6.ggpht.com/_a29lGRJwo0E/TBqOK_tUKmI/AAAAAAAAVbw/UloKpjsKP3c/s144-c/31012332.jpg",
"http://lh3.ggpht.com/_55Lla4_ARA4/TB6xbyxxJ9I/AAAAAAABTWo/GKe24SwECns/s144-c/Bluebird%20049.JPG",
"http://lh3.ggpht.com/_iVnqmIBYi4Y/TCaOH6rRl1I/AAAAAAAA1qg/qeMerYQ6DYo/s144-c/Kwiat_100626_0016.jpg",
"http://lh6.ggpht.com/_QFsB_q7HFlo/TCItd_2oBkI/AAAAAAAAFsk/4lgJWweJ5N8/s144-c/3705226938_d6d66d6068_o.jpg",
"http://lh5.ggpht.com/_JTI0xxNrKFA/TBsKQ9uOGNI/AAAAAAAChQg/z8Exh32VVTA/s144-c/CRW_0015-composite.jpg",
"http://lh6.ggpht.com/_loGyjar4MMI/S-InVNkTR_I/AAAAAAAADJY/Fb5ifFNGD70/s144-c/Moving%20Rock.jpg",
"http://lh4.ggpht.com/_L7i4Tra_XRY/TBtxjScXLqI/AAAAAAAAE5o/ue15HuP8eWw/s144-c/opera%20house%20II.jpg",
"http://lh3.ggpht.com/_rfAz5DWHZYs/S9cstBTv1iI/AAAAAAAAeYA/EyZPUeLMQ98/s144-c/DSC_6425.jpg",
"http://lh6.ggpht.com/_iGI-XCxGLew/S-iYQWBEG-I/AAAAAAAACB8/JuFti4elptE/s144-c/norvig-polar-bear.jpg",
"http://lh3.ggpht.com/_M3slUPpIgmk/SlbnavqG1cI/AAAAAAAACvo/z6-CnXGma7E/s144-c/mf_003.jpg",
"http://lh4.ggpht.com/_loGyjar4MMI/S-InQvd_3hI/AAAAAAAADIw/dHvCFWfyHxQ/s144-c/Rainbokeh.jpg",
"http://lh4.ggpht.com/_yy6KdedPYp4/SB5rpK3Zv0I/AAAAAAAAOM8/mokl_yo2c9E/s144-c/Point%20Reyes%20road%20.jpg",
"http://lh5.ggpht.com/_6_dLVKawGJA/SMwq86HlAqI/AAAAAAAAG5U/q1gDNkmE5hI/s144-c/mobius-glow.jpg",
"http://lh3.ggpht.com/_QFsB_q7HFlo/TCItc19Jw3I/AAAAAAAAFs4/nPfiz5VGENk/s144-c/4551649039_852be0a952_o.jpg",
"http://lh6.ggpht.com/_TQY-Nm7P7Jc/TBpjA0ks2MI/AAAAAAAABcI/J6ViH98_poM/s144-c/IMG_6517.jpg",
"http://lh3.ggpht.com/_rfAz5DWHZYs/S9cLAeKuueI/AAAAAAAAeYU/E19G8DOlJRo/s144-c/DSC_4397_8_9_tonemapped2.jpg",
"http://lh4.ggpht.com/_TQY-Nm7P7Jc/TBpi6rKfFII/AAAAAAAABbg/79FOc0Dbq0c/s144-c/david_lee_sakura.jpg",
"http://lh3.ggpht.com/_TQY-Nm7P7Jc/TBpi8EJ4eDI/AAAAAAAABb0/AZ8Cw1GCaIs/s144-c/Hokkaido%20Swans.jpg",
"http://lh3.ggpht.com/_1aZMSFkxSJI/TCIjB6od89I/AAAAAAAACHM/CLWrkH0ziII/s144-c/079.jpg",
"http://lh5.ggpht.com/_loGyjar4MMI/S-InWuHkR9I/AAAAAAAADJE/wD-XdmF7yUQ/s144-c/Colorado%20River%20Sunset.jpg",
"http://lh3.ggpht.com/_0YSlK3HfZDQ/TCExCG1Zc3I/AAAAAAAAX1w/9oCH47V6uIQ/s144-c/3138923889_a7fa89cf94_o.jpg",
"http://lh6.ggpht.com/_K29ox9DWiaM/TAXe4Fi0xTI/AAAAAAAAVIY/zZA2Qqt2HG0/s144-c/IMG_7100.JPG",
"http://lh6.ggpht.com/_0YSlK3HfZDQ/TCEx16nJqpI/AAAAAAAAX1c/R5Vkzb8l7yo/s144-c/4235400281_34d87a1e0a_o.jpg",
"http://lh4.ggpht.com/_8zSk3OGcpP4/TBsOVXXnkTI/AAAAAAAAAEo/0AwEmuqvboo/s144-c/yosemite_forrest.jpg",
"http://lh4.ggpht.com/_6_dLVKawGJA/SLZToqXXVrI/AAAAAAAAG5k/7fPSz_ldN9w/s144-c/coastal-1.jpg",
"http://lh4.ggpht.com/_WW8gsdKXVXI/TBpVr9i6BxI/AAAAAAABhNg/KC8aAJ0wVyk/s144-c/IMG_6233_1_2-2.jpg",
"http://lh3.ggpht.com/_loGyjar4MMI/S-InS0tJJSI/AAAAAAAADHU/E8GQJ_qII58/s144-c/Windmills.jpg",
"http://lh4.ggpht.com/_loGyjar4MMI/S-InbXaME3I/AAAAAAAADHo/4gNYkbxemFM/s144-c/Frantic.jpg",
"http://lh5.ggpht.com/_loGyjar4MMI/S-InKAviXzI/AAAAAAAADHA/NkyP5Gge8eQ/s144-c/Rice%20Fields.jpg",
"http://lh3.ggpht.com/_loGyjar4MMI/S-InZA8YsZI/AAAAAAAADH8/csssVxalPcc/s144-c/Seahorse.jpg",
"http://lh3.ggpht.com/_syQa1hJRWGY/TBwkCHcq6aI/AAAAAAABBEg/R5KU1WWq59E/s144-c/Antelope.JPG",
"http://lh5.ggpht.com/_MoEPoevCLZc/S9fHzNgdKDI/AAAAAAAADwE/UAno6j5StAs/s144-c/c84_7083.jpg",
"http://lh4.ggpht.com/_DJGvVWd7IEc/TBpRsGjdAyI/AAAAAAAAFNw/rdvyRDgUD8A/s144-c/Free.jpg",
"http://lh6.ggpht.com/_iO97DXC99NY/TBwq3_kmp9I/AAAAAAABcz0/apq1ffo_MZo/s144-c/IMG_0682_cp.jpg",
"http://lh4.ggpht.com/_7V85eCJY_fg/TBpXudG4_PI/AAAAAAAAPEE/8cHJ7G84TkM/s144-c/20100530_120257_0273-Edit-2.jpg" };
public TestListLoaderAsync(Context context) {
super(context);
}
@Override
public List<TestItemModel> loadInBackground() {
System.out.println("TestListLoader.loadInBackground");
// You should perform the heavy task of getting data from
// Internet or database or other source
// Here, we are generating some Sample data
// Create corresponding array of entries and load with data.
List<TestItemModel> entries = new ArrayList<TestItemModel>(5);
entries.add(new TestItemModel("Java", "1", URLS[1]));
entries.add(new TestItemModel("C++", "2", URLS[2]));
entries.add(new TestItemModel("Python", "3", URLS[3]));
entries.add(new TestItemModel("JavaScript", "4", URLS[4]));
entries.add(new TestItemModel("D", "5", URLS[5]));
entries.add(new TestItemModel("C", "6", URLS[6]));
entries.add(new TestItemModel("Perl", "7", URLS[7]));
entries.add(new TestItemModel("Fortran", "8", URLS[8]));
entries.add(new TestItemModel("Cobalt", "9", URLS[9]));
entries.add(new TestItemModel("Ruby", "10", URLS[10]));
entries.add(new TestItemModel("Pascal", "11", URLS[11]));
entries.add(new TestItemModel("HTML", "12", URLS[12]));
entries.add(new TestItemModel("CSS", "13", URLS[13]));
entries.add(new TestItemModel("PHP", "14", URLS[14]));
entries.add(new TestItemModel("MYSQL", "15", URLS[15]));
entries.add(new TestItemModel("Fortran", "8", URLS[16]));
entries.add(new TestItemModel("Cobalt", "9", URLS[17]));
entries.add(new TestItemModel("Ruby", "10", URLS[18]));
entries.add(new TestItemModel("Pascal", "11", URLS[19]));
entries.add(new TestItemModel("HTML", "12", URLS[20]));
entries.add(new TestItemModel("CSS", "13", URLS[21]));
entries.add(new TestItemModel("PHP", "14", URLS[22]));
entries.add(new TestItemModel("MYSQL", "15", URLS[23]));
TestItemModel lastItem = new TestItemModel("C#", "16", URLS[0]);
lastItem.setId("TestingId");
entries.add(lastItem);
return entries;
}
/**
* Called when there is new data to deliver to the client. The super class
* will take care of delivering it; the implementation here just adds a
* little more logic.
*/
@Override
public void deliverResult(List<TestItemModel> listOfData) {
if (isReset()) {
// An async query came in while the loader is stopped. We
// don't need the result.
if (listOfData != null) {
onReleaseResources(listOfData);
}
}
List<TestItemModel> oldApps = listOfData;
_models = listOfData;
if (isStarted()) {
// If the Loader is currently started, we can immediately
// deliver its results.
super.deliverResult(listOfData);
}
// At this point we can release the resources associated with
// 'oldApps' if needed; now that the new result is delivered we
// know that it is no longer in use.
if (oldApps != null) {
onReleaseResources(oldApps);
}
}
/**
* Handles a request to start the Loader.
*/
@Override
protected void onStartLoading() {
if (_models != null) {
// If we currently have a result available, deliver it
// immediately.
deliverResult(_models);
}
if (takeContentChanged() || _models == null) {
// If the data has changed since the last time it was loaded
// or is not currently available, start a load.
forceLoad();
}
}
/**
* Handles a request to stop the Loader.
*/
@Override
protected void onStopLoading() {
// Attempt to cancel the current load task if possible.
cancelLoad();
}
/**
* Handles a request to cancel a load.
*/
@Override
public void onCanceled(List<TestItemModel> apps) {
super.onCanceled(apps);
// At this point we can release the resources associated with 'apps'
// if needed.
onReleaseResources(apps);
}
/**
* Handles a request to completely reset the Loader.
*/
@Override
protected void onReset() {
super.onReset();
// Ensure the loader is stopped
onStopLoading();
// At this point we can release the resources associated with 'apps'
// if needed.
if (_models != null) {
onReleaseResources(_models);
_models = null;
}
}
/**
* Helper function to take care of releasing resources associated with an
* actively loaded data set.
*/
protected void onReleaseResources(List<TestItemModel> apps) {
}
}
推荐答案
该onScrollListener有很多，你可以使用有用的信息。以下是我与一个GridView（相同的侦听器作为一个ListView）。所有的变量都是整数。我计算的预读点使用可用的信息。
The onScrollListener has a lot of useful info that you can use. Here is what I did with a GridView (same listener as a ListView). All of the variables are ints. I calculated a read ahead point using the available info.
mGridView.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if (visibleItemCount > 0) {
// First time: init read ahead variables
if (mPageSize == 0) {
mPageSize = visibleItemCount;
mReadAheadSize = mPageSize * 2;
mRATrigger = visibleItemCount + mReadAheadSize;
}
int lastVisibleItem = firstVisibleItem + visibleItemCount;
int lastRAItem = lastVisibleItem + mReadAheadSize;
if (lastRAItem >= mRATrigger) {
// At read-ahead point. Reset to next read-ahead point and call
// call a method to add more items to the ListView.
}
这篇关于ListFragment载入更多的滚动结束的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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