java - 仅在提交搜索后显示 Recyclerview
问题描述
我希望 MainActivity 在启动时为空,并且只有在提交搜索后,recyclerview 才会显示结果(因此它永远不会显示整个 recyclerview 列表)。截至目前,该应用程序可以正常工作,但 MainActivity 从推送到回收器视图的所有数据开始。
如果列表很大,它会影响性能,所以我需要一种方法将其启动为空(或填充但不显示它)并仅显示搜索结果的 recyclerview,或者创建一个将在 MainActivity 之前启动的新活动只有 Searchview 和 MainActivity 上的结果。
这是我当前的代码:
MainActivity.class(不包括导入)
public class MainActivity extends AppCompatActivity{
private AdapterListe adapter;
private RESTTask asyncTask;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RecyclerView recyclerView = findViewById(R.id.lista);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
adapter = new AdapterListe(this);
//adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
asyncTask = new RESTTask();
asyncTask.execute( getString(R.string.REST_URL));
}
private class RESTTask extends AsyncTask<String, Void, List<Ontologija>> {
protected List<Ontologija> doInBackground(String... adresa) {
String stringUrl = adresa[0];
List<Ontologija> vrati = null;
try {
URL myUrl = new URL(stringUrl);
HttpURLConnection connection = (HttpURLConnection)
myUrl.openConnection();
connection.setRequestMethod("GET");
connection.setReadTimeout(15000);
connection.setConnectTimeout(15000);
connection.connect();
InputStreamReader streamReader = new
InputStreamReader(connection.getInputStream());
BufferedReader reader = new BufferedReader(streamReader);
Type listType = new TypeToken<ArrayList<Ontologija>>() {
}.getType();
vrati = new Gson().fromJson(reader, listType);
reader.close();
streamReader.close();
} catch (Exception e) {
e.printStackTrace();
}
return vrati;
}
protected void onProgressUpdate(Integer... progress) {
}
protected void onPostExecute(List<Ontologija> podaci) {
adapter.setPodaci(podaci);
adapter.notifyDataSetChanged();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
MenuItem item = menu.findItem(R.id.search_icon);
SearchView searchView = (SearchView) item.getActionView();
searchView.setQueryHint("Pretraži...");
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
adapter.getFilter().filter(query);
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
//adapter.getFilter().filter(newText);
return false;
}
});
return super.onCreateOptionsMenu(menu);
}
}
适配器
public class AdapterListe extends RecyclerView.Adapter<AdapterListe.Red> implements Filterable {
private List<Ontologija> podaci;
private List<Ontologija> podaciTemp;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// Podatke proslijedimo kroz konstruktor
public AdapterListe(Context context) {
this.mInflater = LayoutInflater.from(context);
podaci = new ArrayList<>();
}
// napuni predložak red (datoteka red_liste.xml)
@Override
public Red onCreateViewHolder(ViewGroup roditelj, int viewType) {
podaciTemp = new ArrayList<>(podaci);
View view = mInflater.inflate(R.layout.red_liste, roditelj, false);
return new Red(view);
}
// Veže podatke za svaki red
@Override
public void onBindViewHolder(Red red, int position) {
Ontologija o = podaci.get(position);
red.naziv.setText(o.getNaziv());
red.tip.setText(o.getTip());
red.opis.setText(o.getOpis());
red.anotacija.setText(o.getAnotacija());
}
// Ukupan broj redova (mora biti implementirano)
@Override
public int getItemCount() {
return podaci==null ? 0 : podaci.size();
}
// Pohranjuje i reciklira pogled kako se prolazi kroz listu
public class Red extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView naziv;
private TextView tip;
private TextView opis;
private TextView anotacija;
Red(View itemView) {
super(itemView);
naziv = itemView.findViewById(R.id.naziv);
tip = itemView.findViewById(R.id.tip);
opis = itemView.findViewById(R.id.opis);
anotacija = itemView.findViewById(R.id.anotacija);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// klikom na listu dobijemo samo poziciju koju stavku liste smo odabrali.
// Ova metoda pomaže da na osnovu pozicije dobijemo cijeli objekt u toj stavci
public Ontologija getItem(int id) {
return podaci.get(id);
}
public void setPodaci(List<Ontologija> itemList) {
this.podaci = itemList;
}
// dopusti hvatanje odabira (klik/dotakni)
public void setClickListener(ItemClickListener itemClickListener) {
this.mClickListener = itemClickListener;
}
// potrebno kako bi mogli hvatati klikove/dodire
public interface ItemClickListener {
void onItemClick(View view, int position);
}
@Override
public Filter getFilter() {
return new Filter() {
//background
@Override
protected FilterResults performFiltering(CharSequence constraint) {
List<Ontologija> filteredList = new ArrayList<>();
if (constraint.toString().isEmpty()) {
filteredList.addAll(podaciTemp);
} else {
if(constraint.toString().length() >= 3) {
for (Ontologija element : podaciTemp) {
if (element.getNaziv().toLowerCase().contains(constraint.toString().toLowerCase())) {
filteredList.add(element);
}
}
}
}
FilterResults filterResults = new FilterResults();
filterResults.values = filteredList;
return filterResults;
}
//ui
@Override
protected void publishResults(CharSequence constraint, FilterResults filterResults) {
podaci.clear();
podaci.addAll((Collection<? extends Ontologija>) filterResults.values);
notifyDataSetChanged();
}
};
}
}
无论是代码、一些参考视频/帖子还是基本上任何类型的帮助都将不胜感激,但到目前为止,我只看到了整个 recyclerview 的基本过滤器 searchview 教程,对我的具体情况没有任何帮助。
解决方案
如果您不想显示,只需删除 notifyDataSetChanged
protected void onPostExecute(List<Ontologija> podaci) {
adapter.setPodaci(podaci);
//adapter.notifyDataSetChanged();
}
编辑 :
if (!query.isEmpty()) {
adapter.getFilter().filter(query);
}
或使用searchView.clearFocus();
推荐阅读
- r - 检查R中是否存在URL
- angular - Angular 6 Material - 无法读取未定义的属性“navigateByUrl”
- android - 如果不使用 PRO 帐户时使用 Webview,我可以在 android native 上使用 Vimeo 原生视频流吗?
- ios - UIView 切出任意数量的透明孔
- java - 我在 JTabbedPane 外部的框架内收到 JButton 的“错误:找不到符号”
- java - 无法启动活动 ComponentInfo:尝试在空对象引用上调用虚拟方法
- numpy - 通过重复的函数调用将数组附加到自身
- java - 如何在子类中正确调用超类的构造函数?
- python - NLTK Tokenizer 的算法复杂度
- statsmodels - 使用 statsmodels.formula.api 中的 ols 只有一个常数项?