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我一直在嘗試很多事情來解決這個問題，並尋找解決方案几個小時，我需要一些幫助。我有一個列表視圖，從MySQL導入數據並在Listview中獲取數據。我的問題：列表視圖重複的項目（只有前20，然後我使用「loadmoredata」，我收到滾動downn新20項，但沒有更多的重複項目了）。所以，我第一次看到40個項目（重複20次）。如何使用LinkedHashSet刪除ArrayList <Object>中的重複項？
我試過LinkedHashSet，但我不能得到那個作品。有什麼建議麼？
private ArrayList<Usuarios> items;
private Set<Usuarios> set;
private ArrayList<Usuarios> newList;
Activity activity;
Usuarios_adapter adapter;
...
listView = (ListView) findViewById(R.id.listView);
listView.setOnItemClickListener(this);
activity=this;
items=new ArrayList<Usuarios>();
set = new LinkedHashSet<Usuarios>(items);
newList = new ArrayList<Usuarios>(set);
adapter=new Usuarios_adapter(activity,newList);
listView.setAdapter(adapter);
//more code here
}
class BackTask extends AsyncTask<Void,Void,Void>{
protected void onPreExecute(){
super.onPreExecute();
listView.addFooterView(footerView);
}
protected Void doInBackground(Void...params) {
HashMap<String,String> params2 = new HashMap<>();
params2.put(Config.TAG_PESO,lastpeso2);
RequestHandler rh = new RequestHandler();
String s = rh.sendPostRequest(Config.URL_GET_ALL3, params2);
JSON_STRING = s;
JSONObject jsonObject = null;
try {
if(isLoadMore){
isLoadMore = false; }
jsonObject = new JSONObject(JSON_STRING);
JSONArray result = jsonObject.getJSONArray(Config.TAG_JSON_ARRAY);
for (int i = 0; i < result.length(); i++) {
JSONObject jo = result.getJSONObject(i);
String id = String.valueOf(jo.getInt(Config.TAG_ID));
String nombre = jo.getString(Config.TAG_NOMBRE);
String email = jo.getString(Config.TAG_EMAIL);
String foto = jo.getString(Config.TAG_FOTO);
String peso = jo.getString(Config.TAG_PESO);
String vasos = jo.getString(Config.TAG_VASOS);
String seguimiento = jo.getString(Config.TAG_SEGUIMIENTO);
String aplausos = jo.getString(Config.TAG_APLAUSOS);
String followers = jo.getString(Config.TAG_FOLLOWERS);
Usuarios user = new Usuarios(id, nombre, email, foto, peso, vasos, seguimiento ,aplausos, followers);
//items.add(user); //this would be the original, who give me duplicated items
newList.add(user);//this is the second arraylist
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void result){
listView.removeFooterView(footerView);
adapter.notifyDataSetChanged();
}
}
BackTask bt = new BackTask();
bt.execute();
編輯： 隨着@Japu_D_Cret修飾
private ArrayList<Usuarios> items;
private Activity activity;
private Usuarios_adapter adapter;
.....
activity=this;
items=new ArrayList<Usuarios>();
adapter=new Usuarios_adapter(activity,items);
listView.setAdapter(adapter);
....
Set<Usuarios> set = new HashSet<>(items);
for (int i = 0; i < result.length(); i++) {
JSONObject jo = result.getJSONObject(i);
String id = String.valueOf(jo.getInt(Config.TAG_ID));
String nombre = jo.getString(Config.TAG_NOMBRE);
String email = jo.getString(Config.TAG_EMAIL);
String foto = jo.getString(Config.TAG_FOTO);
String peso = jo.getString(Config.TAG_PESO);
String vasos = jo.getString(Config.TAG_VASOS);
String seguimiento = jo.getString(Config.TAG_SEGUIMIENTO);
String aplausos = jo.getString(Config.TAG_APLAUSOS);
String followers = jo.getString(Config.TAG_FOLLOWERS);
Usuarios user = new Usuarios(id, nombre, email, foto, peso, vasos, seguimiento ,aplausos, followers);
//items.add(user);
set.add(user);
}
//clear the list, so no duplicates occurr
items.clear();
//copy the temporary set to the items
items.addAll(set);
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
這是我getView
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
LayoutInflater inflator = activity.getLayoutInflater();
convertView = inflator.inflate(R.layout.b_server_list_item, null);
holder = new ViewHolder();
holder.id = (TextView) convertView.findViewById(R.id.id);
holder.email = (TextView) convertView.findViewById(R.id.list_email);
holder.nombre = (TextView) convertView.findViewById(R.id.Nombre);
holder.peso = (TextView) convertView.findViewById(R.id.Peso);
holder.vasos = (TextView) convertView.findViewById(R.id.Vasos);
holder.seguimiento = (TextView) convertView.findViewById(R.id.Seguimiento);
holder.followers = (TextView) convertView.findViewById(R.id.tv_followers);
holder.aplausos = (TextView) convertView.findViewById(R.id.tv_aplausos);
holder.picture = (ImageView) convertView.findViewById(R.id.foto_profile);
holder.foto_id = (TextView) convertView.findViewById(R.id.foto_id);
holder.rank = (TextView) convertView.findViewById(R.id.Rank);
holder.picture = (ImageView) convertView.findViewById(R.id.foto_profile);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.id.setText(items.get(position).getId());
holder.email.setText(items.get(position).getEmail());
holder.nombre.setText(items.get(position).getNombre());
holder.peso.setText(items.get(position).getPeso());
holder.vasos.setText(items.get(position).getVasos());
holder.seguimiento.setText(items.get(position).getSeguimiento());
holder.followers.setText(items.get(position).getFollowers());
holder.aplausos.setText(items.get(position).getAplausos());
holder.foto_id.setText(items.get(position).getFoto());
final int pos = position+1;
holder.rank.setText("" + pos);
String fotoid = holder.foto_id.getText().toString();
if(fotoid.contains("avatar_a")){holder.picture.setImageResource(R.drawable.avatar_a);}
if(fotoid.contains("avatar_b")){holder.picture.setImageResource(R.drawable.avatar_b);}
return convertView;
}
您不使用Set。您將內容複製到newList，但不實際使用它。如果您的問題得到解答，請參閱我的回答 –
，請標記答案 –