Android listview的Onscroll侦听器不是';行不通
我有一个listview,当它达到20个列表项时,它应该加载更多的列表项。我添加了onscroll listener来实现这一点 但它没有像我预期的那样工作 要完全理解,请看这个 我的代码:Android listview的Onscroll侦听器不是';行不通,android,listview,onscrolllistener,Android,Listview,Onscrolllistener,我有一个listview,当它达到20个列表项时,它应该加载更多的列表项。我添加了onscroll listener来实现这一点 但它没有像我预期的那样工作 要完全理解,请看这个 我的代码: public class InterActivity extends Activity implements OnItemClickListener, OnItemLongClickListener { ListView listview; List<ParseObjec
public class InterActivity extends Activity implements OnItemClickListener, OnItemLongClickListener
{
ListView listview;
List<ParseObject> ob;
ProgressDialog mProgressDialog;
FinalAdapter adapter;
List<CodeList> codelist = null;
SharedPreference shrdPreference;
boolean loadingMore = false;
private int limit = 20;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.inter_layout);
shrdPreference = new SharedPreference();
//Execute RemoteDataTask AsyncTask
new RemoteDataTask().execute();
}
private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(InterActivity.this);
// Set progressdialog title
mProgressDialog.setTitle("Loading");
// Set progressdialog message
mProgressDialog.setMessage("Please wait loading ...");
mProgressDialog.setIndeterminate(false);
mProgressDialog.setCancelable(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
//my own doinbackground ()
}
} catch (ParseException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
// Locate the listview in listview_main.xml
listview = (ListView) findViewById(R.id.inter_layoutListView);
// Pass the results into ListViewAdapter.java
adapter = new FinalAdapter(InterActivity.this,
codelist);
AlphaInAnimationAdapter animationAdapter = new AlphaInAnimationAdapter(adapter);
animationAdapter.setAbsListView(listview);
View loadMoreView = ((LayoutInflater)InterActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE))
.inflate(R.layout.loadmore, null, false);
listview.addFooterView(loadMoreView);
// Binds the Adapter to the ListView
listview.setAdapter(adapter);
listview.setOnItemClickListener(InterActivity.this);
listview.setOnItemLongClickListener(InterActivity.this);
// Close the progressdialog
mProgressDialog.dismiss();
listview.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)){
new LoadMoreDataTask().execute();
}
}
});
}
}
private class LoadMoreDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
// my own doinbackground ()
}
@Override
protected void onPostExecute(Void result) {
// Locate listview last item
int position = listview.getLastVisiblePosition();
// Pass the results into ListViewAdapter.java
adapter = new FinalAdapter(InterActivity.this, codelist);
// Binds the Adapter to the ListView
listview.setAdapter(adapter);
// Show the latest retrived results on the top
listview.setSelectionFromTop(position, 0);
}
}
公共类交互扩展活动实现了OnItemClickListener、OnItemLongClickListener
{
列表视图列表视图;
列表ob;
进程对话框;
最终适配器;
列表代码列表=空;
SharedReference shrdReference;
boolean loadingMore=false;
私人整数限制=20;
@凌驾
创建时的公共void(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.inter_layout);
shrdReference=新的SharedReference();
//执行RemoteDataTaskAsyncTask
新建RemoteDataTask().execute();
}
私有类RemoteDataTask扩展了AsyncTask{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
//创建一个progressdialog
mProgressDialog=新建ProgressDialog(InterActivity.this);
//设置进程对话框标题
mProgressDialog.setTitle(“加载”);
//设置进程对话框消息
设置消息(“请等待加载…”);
mProgressDialog.setUndeterminate(false);
mProgressDialog.setCancelable(假);
//显示进度对话框
mProgressDialog.show();
}
@凌驾
受保护的Void doInBackground(Void…参数){
//我自己的背景()
}
}捕获(解析异常){
Log.e(“Error”,e.getMessage());
e、 printStackTrace();
}
返回null;
}
@凌驾
受保护的void onPostExecute(void结果){
//在listview_main.xml中找到listview
listview=(listview)findViewById(R.id.inter_layoutListView);
//将结果传递到ListViewAdapter.java中
适配器=新的FinalAdapter(InterActivity.this,
代码表);
AlphaInAnimationAdapter animationAdapter=新的AlphaInAnimationAdapter(适配器);
animationAdapter.setAbsListView(listview);
View loadMoreView=((LayoutFlater)交互性.this.getSystemService(Context.LAYOUT\u INFLATER\u SERVICE))
.充气(R.layout.loadmore,空,假);
addFooterView(loadMoreView);
//将适配器绑定到ListView
setAdapter(适配器);
setOnItemClickListener(InterActivity.this);
setOnItemLongClickListener(InterActivity.this);
//关闭progressdialog
mProgressDialog.disclose();
setOnScrollListener(新的OnScrollListener(){
@凌驾
public void onScrollStateChanged(AbsListView视图,int scrollState){}
@凌驾
public void onScroll(AbsListView视图,int firstVisibleItem,
int visibleItemCount,int totalItemCount){
int lastInScreen=firstVisibleItem+visibleItemCount;
如果((lastInScreen==totalItemCount)&&!(loadingMore)){
新建LoadMoreDataTask().execute();
}
}
});
}
}
私有类LoadMoreDataTask扩展了AsyncTask{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
}
@凌驾
受保护的Void doInBackground(Void…参数){
//我自己的背景()
}
@凌驾
受保护的void onPostExecute(void结果){
//找到listview最后一项
int position=listview.getLastVisiblePosition();
//将结果传递到ListViewAdapter.java中
adapter=newfinaladapter(InterActivity.this,codelist);
//将适配器绑定到ListView
setAdapter(适配器);
//在顶部显示最新检索结果
listview.setSelectionFromTop(位置0);
}
}
将onScroll()更改为
if (!loadingMore && lastInScreen >= totalItemCount && totalItemCount > 0)
new LoadMoreDataTask().execute();
将onScroll()
更改为
if (!loadingMore && lastInScreen >= totalItemCount && totalItemCount > 0)
new LoadMoreDataTask().execute();
请看这里的提示请看这里的提示