我正在开发android应用程序，我想在listview中显示json数据并带有加载更多按钮，但是当我单击加载更多按钮时，旧数据被新数据替换，我希望同时显示新旧数据。Lihstview应该显示所有数据在下面的代码中有什么问题
public class Newjava extends Activity {
JSONObject jsonobject;
JSONArray jsonarray;
CustomAdapter1 adapter2;
CustomAdapter1 adapter;
ProgressDialog mProgressDialog;
ArrayList<FeedAddress> arraylist;
String url = "http://xxxx.vdv.com/api/fvn/page1";
String arraymovie = "all";
public String string;
ListView listView;
int i = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView) findViewById(R.id.list);
arraylist = new ArrayList<FeedAddress>();
// Retrive JSON Objects from the given website URL in
// JSONfunctions.class
jsonobject = JSONfunctions.getJSONfromURL(url);
try {
// Locate the array name
JSONObject jsonObject1 = jsonobject.getJSONObject("appname");
jsonarray = jsonObject1.getJSONArray("kfnh");
for (int i = 0; i < jsonarray.length(); i++) {
JSONObject post = (JSONObject) jsonarray.getJSONObject(i);
FeedAddress map = new FeedAddress();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.setMovieName(post.getString("movieName"));
map.setName(post.getString("movieActors"));
map.setMovieId(post.getString("movieId"));
String imageUrl = "http://www.xxhbc.com/upload/dv/thumbnail/"
+ post.getString("moviePhoto")
+ post.getString("moviePhotoExt");
map.setImageUrl(imageUrl);
System.out.println("ldhslhdljh " + imageUrl);
// Set the JSON Objects into the array
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
Button btnLoadMore = new Button(this);
btnLoadMore.setText("Load More");
// Adding Load More button to lisview at bottom
listView.addFooterView(btnLoadMore);
// Getting adapter
adapter = new CustomAdapter1(this, arraylist);
listView.setAdapter(adapter);
/**
* Listening to Load More button click event
* */
btnLoadMore.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// Starting a new async task
i += 1;
new DownloadJSON().execute();
}
});
}
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(Newjava.this);
// Set progressdialog title
mProgressDialog.setTitle("APP Name");
mProgressDialog.setIcon(R.drawable.ic_launcher);
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// Create the array
arraylist = new ArrayList<FeedAddress>();
// Retrive JSON Objects from the given website URL in
// JSONfunctions.class
String URL = "http://zvzvs.vczx.com/api/v/page"
+ i;
System.out.println("new url " + URL);
jsonobject = JSONfunctions.getJSONfromURL(URL);
try {
// Locate the array name
JSONObject jsonObject1 = jsonobject
.getJSONObject("fvvzx");
jsonarray = jsonObject1.getJSONArray("allmovies");
for (int i = 0; i < jsonarray.length(); i++) {
JSONObject post = (JSONObject) jsonarray.getJSONObject(i);
FeedAddress map = new FeedAddress();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.setMovieName(post.getString("movieName"));
// map.setName(post.getString("movieActors"));
map.setMovieId(post.getString("movieId"));
String imageUrl = "http://www.vsv.com/upload/vc/thumbnail/"
+ post.getString("moviePhoto")
+ post.getString("moviePhotoExt");
map.setImageUrl(imageUrl);
System.out.println("ldhslhdljh " + imageUrl);
// Set the JSON Objects into the array
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
int currentPosition = listView.getFirstVisiblePosition();
// Appending new data to menuItems ArrayList
adapter = new CustomAdapter1(Newjava.this, arraylist);
listView.setAdapter(adapter);
// Setting new scroll position
listView.setSelectionFromTop(currentPosition + 1, 0);
updateList(string);
}
}
public void updateList(final String string) {
// TODO Auto-generated method stub
listView.setVisibility(View.VISIBLE);
// mProgressDialog.dismiss();
listView.setAdapter(new CustomAdapter1(Newjava.this, arraylist));
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1,
int position, long arg3) {
// TODO Auto-generated method stub
// Toast.makeText(getApplicationContext(),"position[]" ,
// Toast.LENGTH_SHORT).show();
Object o = listView.getItemAtPosition(position);
FeedAddress newsData = (FeedAddress) o;
System.out.println("hgsh " + string);
System.out.println("next " + newsData.getMovieId());
Intent intent = new Intent(Newjava.this,
SingleMenuItemActivity.class);
intent.putExtra("feed", newsData.getMovieId());
intent.putExtra("actor", newsData.getName());
startActivity(intent);
}
});
}
}