在我的应用程序中，我使用 pulltorefresh 和 ScrollListener 概念来显示 facebook 提要数据。正如我们在 Android facebook 应用程序中看到的那样。
这是拉动刷新的代码
listView.setOnRefreshListener(new OnRefreshListener() {
public void onRefresh() {
// Your code to refresh the list contents goes here
scroll=true;
pic.clear();
id.clear();
name.clear();
msg.clear();
img.clear();
profimg.clear();
objid.clear();
comment.clear();
previousTotal = 0;
loading = true;
listView.setAdapter(null);
j=0;
webserv="https://graph.facebook.com/me/home?access_token="+accesstoken;
doInBack dob=new doInBack();
dob.execute();
// doback(webserv);
Log.e("hi","doback called");
// Make sure you call listView.onRefreshComplete()
// when the loading is done. This can be done from here or any
// other place, like on a broadcast receive from your loading
// service or the onPostExecute of your AsyncTask.
// For the sake of this sample, the code will pause here to
// force a delay when invoking the refresh
}
});
我的滚动监听类在这里
listView.setOnScrollListener(new OnScrollListener() {
private int threshold = 0;
//
public void onScrollStateChanged(AbsListView view, int scrollState) {
//
if (scrollState != 0) {
isScrolling = true;
}
else {
isScrolling = false;
adapter.notifyDataSetChanged();
}
}
public void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount)
{
// public void onScrollStateChanged(AbsListView view , int scrollState)
// {
// if (scrollState != 0) {
// listView.getAdapter().isScrolling = true;
// }
// else {
// listView.getAdapter().isScrolling = false;
// listView.getAdapter().notifyDataSetChanged();
// }
// }
// TODO Auto-generated method stub
if (loading) {
if (totalItemCount > previousTotal) {
System.out.println(totalItemCount);
loading = false;
previousTotal = totalItemCount;
}
}
// int lastInScreen = firstVisibleItem + visibleItemCount;
// if (!loading && (totalItemCount - visibleItemCount) ==(firstVisibleItem + threshold)){
if (!loading && (firstVisibleItem + visibleItemCount) >= totalItemCount){
// if(((firstVisibleItem + visibleItemCount) == totalItemCount)){
// if (!(loading) &&(totalItemCount - visibleItemCount) ==(firstVisibleItem + threshold)) {
// clearAllResources();
scroll=false;
// if (!(loading) &&(totalItemCount - visibleItemCount) == (firstVisibleItem + threshold)) {
Log.v("in gridview loading more","grid load");
//
doInBack dob=new doInBack();
dob.execute();
// doback(webserv);
loading = true;
}
}
});
我遇到的问题是，当我使用异步类从 facebookapi 加载数据时，当我拉动列表进行刷新时，scrollListener、totalItemcount 值变为 2。即使我清除了 pullrefresh 中的所有列表，我也不明白它是如何变为 2 的.
重要的是，当我使用普通方法而不是这个 Async 类时，我根本没有遇到这个问题。
Here I am providing both my doback() and async class,I think there is something going wrong when I use Async class.
这是我的异步课程
class doInBack extends AsyncTask<URL, Integer, Long>
{
@Override
protected Long doInBackground(URL... arg0) {
// dialog=MyProgressDialog.show(Wall.this, null,null);
Log.e("hi","doback parsing");
// int count=0;
currentweb= webserv;
try
{
// if(urlval>0){
wallres=UrltoValue.getValuefromUrl(webserv);
Log.e("wallrespages",wallres);
// }
// else{
// wallres=UrltoValue.getValuefromUrl(web+accesstoken);
// Log.e("wallreshome",wallres);
// }
JSONObject jobj1=new JSONObject(wallres);
JSONObject jobj2=jobj1.getJSONObject("paging");
webserv= jobj2.getString( "next");
jsonArray = jobj1.getJSONArray("data");
for(int i=0;i<jsonArray.length();i++){
jsonObject = jsonArray.getJSONObject(i);
if(jsonObject.has("message")||jsonObject.has("picture")) {
try{
// msg[j]=jsonObject.getString("message");
if(jsonObject.has("message"))
{
msg.add(jsonObject.getString("message"));
}
else{
msg.add("");
}
}
catch(Exception e){
e.printStackTrace();
}
try{
// msg[j]=jsonObject.getString("message");
if(jsonObject.has("picture"))
{
String firstpicture=jsonObject.getString("picture");
String secondpicture=firstpicture.replaceAll("_s.jpg", "_n.jpg");
Log.e("picurl",secondpicture);
pic.add(secondpicture);
}
else{
pic.add("");
}
}
catch(Exception e){
e.printStackTrace();
}
objid.add(jsonObject.getString("id"));
JSONObject jobj=jsonObject.getJSONObject("from");
name.add(jobj.getString("name"));
id.add(jobj.getString("id"));
// Log.e("msg",msg);
//
// Log.e("name",name[j]);
// Log.e("id",id[j]);
profimg.add("http://graph.facebook.com/"+id.get(j)+"/picture?type=square");
JSONObject commentjobj=jsonObject.getJSONObject("comments");
comment.add(commentjobj.getString("count"));
weburl.add( currentweb);
Log.e("comment", comment.get(j));
// bitmap[j]= getBitmapFromURL(profimg[j]);
// profimg1.setImageBitmap(bitmap[j]);
// imageLoader.DisplayImage( profimg[j].replace(" ", "%20"), profimg1) ;
// System.out.println( bitmap[j]);
j++;
// f=j;
}
}
// if(jsonObject.getString("message")!=""){
// msg[i]=jsonObject.getString("message");
//
// JSONObject jobj=jsonObject.getJSONObject("from");
// name[i]= jobj.getString("name");
// id[i]=jobj.getString("id");
// Log.e("msg",msg[i]);
// Log.e("name",name[i]);
// Log.e("id",id[i]);
// }
//
// }
}
catch(Exception e)
{
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Long result) {
try
{
System.out.println(scroll);
if(scroll){
// listView.addFooterView(footerView);
adapter=new MySimpleArrayAdapter(Wall.this,R.layout.wall,pic,name,msg,id,profimg,bitmap,comment,objid,weburl);
listView.setAdapter(adapter);
// dialog.dismiss();
listView.postDelayed(new Runnable() {
// @Override
public void run() {
listView.onRefreshComplete();
}
}, 2000);
}
else{
// adapter=new MySimpleArrayAdapter(Wall.this,R.layout.wall,pic,name,msg,id,profimg,bitmap,comment,objid,weburl);
adapter.notifyDataSetChanged();
listView.postDelayed(new Runnable() {
// @Override
public void run() {
listView.onRefreshComplete();
}
}, 2000);
}
}
catch(Exception e)
{
e.printStackTrace();
// dialog.dismiss();
}
}
}
我的正常方法是
public void doback(String url)
{
currentweb=url;
// dialog=MyProgressDialog.show(Wall.this, null,null);
Log.e("hi","doback parsing");
// int count=0;
try
{
// if(urlval>0){
wallres=UrltoValue.getValuefromUrl(currentweb);
Log.e("wallrespages",wallres);
// }
// else{
// wallres=UrltoValue.getValuefromUrl(web+accesstoken);
// Log.e("wallreshome",wallres);
// }
JSONObject jobj1=new JSONObject(wallres);
JSONObject jobj2=jobj1.getJSONObject("paging");
webserv= jobj2.getString( "next");
jsonArray = jobj1.getJSONArray("data");
//
// for(int k=0;k<jsonArray.length();k++){
//
// jsonObject = jsonArray.getJSONObject(k);
// if(jsonObject.has("message")||jsonObject.has("picture")) {
// count++;
// }
// }
// jsonObject=null;
// msg=new String[count];
// name=new String[count];
// id=new String[count];
// profimg=new String[count];
// bitmap=new Bitmap[count];
// pic=new String[count];
for(int i=0;i<jsonArray.length();i++){
jsonObject = jsonArray.getJSONObject(i);
if(jsonObject.has("message")||jsonObject.has("picture")) {
try{
// msg[j]=jsonObject.getString("message");
if(jsonObject.has("message"))
{
msg.add(jsonObject.getString("message"));
}
else{
msg.add("");
}
}
catch(Exception e){
e.printStackTrace();
}
try{
// msg[j]=jsonObject.getString("message");
if(jsonObject.has("picture"))
{
String firstpicture=jsonObject.getString("picture");
String secondpicture=firstpicture.replaceAll("_s.jpg", "_n.jpg");
Log.e("picurl",secondpicture);
pic.add(secondpicture);
}
else{
pic.add("");
}
}
catch(Exception e){
e.printStackTrace();
}
objid.add(jsonObject.getString("id"));
JSONObject jobj=jsonObject.getJSONObject("from");
name.add(jobj.getString("name"));
id.add(jobj.getString("id"));
// Log.e("msg",msg);
//
// Log.e("name",name[j]);
// Log.e("id",id[j]);
profimg.add("http://graph.facebook.com/"+id.get(j)+"/picture?type=square");
JSONObject commentjobj=jsonObject.getJSONObject("comments");
comment.add(commentjobj.getString("count"));
weburl.add(url);
Log.e("comment", comment.get(j));
// bitmap[j]= getBitmapFromURL(profimg[j]);
// profimg1.setImageBitmap(bitmap[j]);
// imageLoader.DisplayImage( profimg[j].replace(" ", "%20"), profimg1) ;
// System.out.println( bitmap[j]);
j++;
// f=j;
}
}
// if(jsonObject.getString("message")!=""){
// msg[i]=jsonObject.getString("message");
//
// JSONObject jobj=jsonObject.getJSONObject("from");
// name[i]= jobj.getString("name");
// id[i]=jobj.getString("id");
// Log.e("msg",msg[i]);
// Log.e("name",name[i]);
// Log.e("id",id[i]);
// }
//
// }
}
catch(Exception e)
{
e.printStackTrace();
}
try
{
System.out.println(scroll);
if(scroll){
adapter=new MySimpleArrayAdapter(Wall.this,R.layout.wall,pic,name,msg,id,profimg,bitmap,comment,objid,weburl);
listView.setAdapter(adapter);
listView.postDelayed(new Runnable() {
// @Override
public void run() {
listView.onRefreshComplete();
}
}, 2000);
dialog.dismiss();
}
else{
// adapter=new MySimpleArrayAdapter(Wall.this,R.layout.wall,pic,name,msg,id,profimg,bitmap,comment,objid,weburl);
adapter.notifyDataSetChanged();
listView.postDelayed(new Runnable() {
// @Override
public void run() {
listView.onRefreshComplete();
}
}, 2000);
}
}
catch(Exception e)
{
e.printStackTrace();
// dialog.dismiss();
}
}