在onCreate()方法中，我称之为Asynctask：
private class getAlbumsData extends AsyncTask<Void, Void, Void> {
LinearLayout linlaHeaderProgress = (LinearLayout) findViewById(R.id.linlaHeaderProgress);
@Override
protected void onPreExecute() {
// SHOW THE PROGRESS BAR (SPINNER) WHILE LOADING ALBUMS
linlaHeaderProgress.setVisibility(View.VISIBLE);
}
@Override
protected Void doInBackground(Void... params) {
// CHANGE THE LOADING MORE STATUS TO PREVENT DUPLICATE CALLS FOR
// MORE DATA WHILE LOADING A BATCH
loadingMore = true;
// SET THE INITIAL URL TO GET THE FIRST LOT OF ALBUMS
URL = "https://graph.facebook.com/" + initialUserID
+ "/albums&access_token="
+ Utility.mFacebook.getAccessToken() + "?limit=10";
try {
HttpClient hc = new DefaultHttpClient();
HttpGet get = new HttpGet(URL);
HttpResponse rp = hc.execute(get);
if (rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
String queryAlbums = EntityUtils.toString(rp.getEntity());
JSONObject JOTemp = new JSONObject(queryAlbums);
JSONArray JAAlbums = JOTemp.getJSONArray("data");
if (JAAlbums.length() == 0) {
stopLoadingData = true;
Runnable run = new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"No more Albums", Toast.LENGTH_SHORT)
.show();
}
};
Albums.this.runOnUiThread(run);
} else {
// PAGING JSONOBJECT
if (JOTemp.has("paging")) {
JSONObject JOPaging = JOTemp.getJSONObject("paging");
if (JOPaging.has("next")) {
String initialpagingURL = JOPaging
.getString("next");
String[] parts = initialpagingURL.split("limit=10");
String getLimit = parts[1];
pagingURL = "https://graph.facebook.com/"
+ initialUserID + "/albums&access_token="
+ Utility.mFacebook.getAccessToken()
+ "?limit=10" + getLimit;
} else {
stopLoadingData = true;
Runnable run = new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"No more Albums",
Toast.LENGTH_SHORT).show();
}
};
Albums.this.runOnUiThread(run);
}
} else {
stopLoadingData = true;
Runnable run = new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"No more Albums",
Toast.LENGTH_SHORT).show();
}
};
Albums.this.runOnUiThread(run);
}
getAlbums albums;
for (int i = 0; i < JAAlbums.length(); i++) {
JSONObject JOAlbums = JAAlbums.getJSONObject(i);
if (JOAlbums.has("link")) {
albums = new getAlbums();
// GET THE ALBUM ID
if (JOAlbums.has("id")) {
albums.setAlbumID(JOAlbums.getString("id"));
} else {
albums.setAlbumID(null);
}
// GET THE ALBUM NAME
if (JOAlbums.has("name")) {
albums.setAlbumName(JOAlbums
.getString("name"));
} else {
albums.setAlbumName(null);
}
// GET THE ALBUM COVER PHOTO
if (JOAlbums.has("cover_photo")) {
albums.setAlbumCover("https://graph.facebook.com/"
+ JOAlbums.getString("cover_photo")
+ "/picture?type=normal"
+ "&access_token="
+ Utility.mFacebook
.getAccessToken());
} else {
albums.setAlbumCover("https://graph.facebook.com/"
+ JOAlbums.getString("id")
+ "/picture?type=album"
+ "&access_token="
+ Utility.mFacebook
.getAccessToken());
}
// GET THE ALBUM'S PHOTO COUNT
if (JOAlbums.has("count")) {
albums.setAlbumPhotoCount(JOAlbums
.getString("count"));
} else {
albums.setAlbumPhotoCount("0");
}
arrAlbums.add(albums);
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
// SET THE ADAPTER TO THE LISTVIEW
lv.setAdapter(adapter);
// CHANGE THE LOADING MORE STATUS
loadingMore = false;
// HIDE THE PROGRESS BAR (SPINNER) AFTER LOADING ALBUMS
linlaHeaderProgress.setVisibility(View.GONE);
}
}
为了完整起见，这里是我用来为一个永无止境的列表获取分页 URL 的内容：
private class loadMoreAlbums extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
// SHOW THE BOTTOM PROGRESS BAR (SPINNER) WHILE LOADING MORE ALBUMS
linlaProgressBar.setVisibility(View.VISIBLE);
}
@Override
protected Void doInBackground(Void... params) {
// SET LOADING MORE "TRUE"
loadingMore = true;
// INCREMENT CURRENT PAGE
current_page += 1;
// Next page request
URL = pagingURL;
// Log.e("NEW URL", URL);
try {
HttpClient hc = new DefaultHttpClient();
HttpGet get = new HttpGet(URL);
HttpResponse rp = hc.execute(get);
if (rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
String queryAlbums = EntityUtils.toString(rp.getEntity());
// Log.e("RESULT", queryAlbums);
JSONObject JOTemp = new JSONObject(queryAlbums);
JSONArray JAAlbums = JOTemp.getJSONArray("data");
if (JAAlbums.length() == 0) {
stopLoadingData = true;
Runnable run = new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"No more Albums", Toast.LENGTH_SHORT)
.show();
}
};
Albums.this.runOnUiThread(run);
} else {
// PAGING JSONOBJECT
JSONObject JOPaging = JOTemp.getJSONObject("paging");
// Log.e("PAGING", JOPaging.toString());
if (JOPaging.has("next")) {
String initialpagingURL = JOPaging
.getString("next");
// Log.e("initialpagingURL", initialpagingURL);
String[] parts = initialpagingURL.split("limit=10");
String getLimit = parts[1];
pagingURL = "https://graph.facebook.com/"
+ initialUserID + "/albums&access_token="
+ Utility.mFacebook.getAccessToken()
+ "?limit=10" + getLimit;
// Log.e("NEW PAGING URL", pagingURL);
} else {
stopLoadingData = true;
Runnable run = new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"No more Albums available",
Toast.LENGTH_SHORT).show();
}
};
Albums.this.runOnUiThread(run);
}
getAlbums albums;
for (int i = 0; i < JAAlbums.length(); i++) {
JSONObject JOAlbums = JAAlbums.getJSONObject(i);
// Log.e("INDIVIDUAL ALBUMS", JOAlbums.toString());
if (JOAlbums.has("link")) {
albums = new getAlbums();
// GET THE ALBUM ID
if (JOAlbums.has("id")) {
albums.setAlbumID(JOAlbums.getString("id"));
} else {
albums.setAlbumID(null);
}
// GET THE ALBUM NAME
if (JOAlbums.has("name")) {
albums.setAlbumName(JOAlbums
.getString("name"));
} else {
albums.setAlbumName(null);
}
// GET THE ALBUM COVER PHOTO
if (JOAlbums.has("cover_photo")) {
albums.setAlbumCover("https://graph.facebook.com/"
+ JOAlbums.getString("cover_photo")
+ "/picture?type=album"
+ "&access_token="
+ Utility.mFacebook
.getAccessToken());
} else {
albums.setAlbumCover("https://graph.facebook.com/"
+ JOAlbums.getString("id")
+ "/picture?type=album"
+ "&access_token="
+ Utility.mFacebook
.getAccessToken());
}
// GET THE ALBUM'S PHOTO COUNT
if (JOAlbums.has("count")) {
albums.setAlbumPhotoCount(JOAlbums
.getString("count"));
} else {
albums.setAlbumPhotoCount("0");
}
arrAlbums.add(albums);
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
// get listview current position - used to maintain scroll position
int currentPosition = lv.getFirstVisiblePosition();
// APPEND NEW DATA TO THE ARRAYLIST AND SET THE ADAPTER TO THE
// LISTVIEW
adapter = new AlbumsAdapter(Albums.this, arrAlbums);
lv.setAdapter(adapter);
// Setting new scroll position
lv.setSelectionFromTop(currentPosition + 1, 0);
// SET LOADINGMORE "FALSE" AFTER ADDING NEW FEEDS TO THE EXISTING
// LIST
loadingMore = false;
// HIDE THE BOTTOM PROGRESS BAR (SPINNER) AFTER LOADING MORE ALBUMS
linlaProgressBar.setVisibility(View.GONE);
}
}
loadMoreAlbums Asynctask从以下设置onScrollListener运行onCreate()：
lv.setOnScrollListener(new OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
int lastInScreen = firstVisibleItem + visibleItemCount;
if ((lastInScreen == totalItemCount) && !(loadingMore)) {
if (stopLoadingData == false) {
// FETCH THE NEXT BATCH OF FEEDS
new loadMoreAlbums().execute();
}
}
}
});
您可以从我的代码中选择相关部分，也可以将其全部使用（当然是在填写一些空白之后）。希望有些帮助。