我是Android编程的新手，我想在我的Baseadapter中创建自定义过滤器。
老实说，当我检查其他问题时，它有点令人困惑，因为他们大多使用Arraylists。我已经创建了一个自定义视图（getView），它将小图标设置到我的ListView中。我已经尝试了很多方法来实现Arraylist示例中的这些自定义Filter，但不知怎的，我陷入了封锁。
如果有人能够至少给我一个带对象的自定义过滤器的方向
，那将会非常有帮助cryptoListAdapter.java
public class cryptoListAdapter extends BaseAdapter {
private Context context;
LayoutInflater mInlfater;
ArrayList<HashMap<String,String>> currencyList;
TextView name;
// Constructor
public cryptoListAdapter(Context context,ArrayList<HashMap<String,String>> currencyList)
{
mInlfater = LayoutInflater.from(context);
this.currencyList = currencyList;
}
@Override
public int getCount() {
return currencyList.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
cryptoPicto cp = new cryptoPicto();
View newView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_crypto_items, null);
name = (TextView) newView.findViewById(R.id.name);
TextView symbol = (TextView) newView.findViewById(R.id.symbol);
ImageView image_list_icon = (ImageView)newView.findViewById(cryptopicto);
//cp.createFinalFileName(name);
HashMap<String, String> map;
map = currencyList.get(position);
name.setText(map.get("name"));
symbol.setText(map.get("symbol"));
Picasso.with(newView.getContext()).load(map.get("cryptopicto")).into(image_list_icon);
return newView;
}
currencyTableView.java
public class currencyTableView extends AppCompatActivity {
private String TAG = currencyTableView.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
private SearchView sv;
private ImageView im;
private static String url = "https//myURLToJSON";
Context context;
cryptoListAdapter adapter;
ArrayList<HashMap<String, String>> currencyList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_currency_table_view);
sv = (SearchView) findViewById(R.id.search_currency);
currencyList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
im = (ImageView) findViewById(R.id.cryptopicto);
new GetCurrencies().execute();
}
// URL to get currencies JSON
private class GetCurrencies extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(currencyTableView.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
databasehandler sh = new databasehandler();
cryptoPicto cp = new cryptoPicto();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONArray jsonArray = new JSONArray(jsonStr);
// looping through currencies
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject c = jsonArray.getJSONObject(i);
String name = c.getString("name");
String symbol = c.getString("symbol");
Double price_usd = c.getDouble("price_usd");
Double price_eur = c.getDouble("price_eur");
Double price_btc = c.getDouble("price_btc");
Double volume_eur = c.getDouble("volume_eur");
Double market_cap_usd = c.getDouble("market_cap_usd");
Double percent_change_1h = c.getDouble("percent_change_1h");
Double percent_change_24h = c.getDouble("percent_change_24h");
Double percent_change_7d = c.getDouble("percent_change_7d");
// tmp hash map for single currency
HashMap<String, String> currency = new HashMap<>();
// create Path to picto Filename
cp.createFinalFileName(name);
// adding each child node to HashMap key => value
currency.put("cryptopicto", cp.getFinalFileName());
currency.put("name", name);
currency.put("symbol", symbol);
// adding currency to currencyList
currencyList.add(currency);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
adapter = new cryptoListAdapter(
currencyTableView.this, currencyList) {
};
lv.setAdapter(adapter);
sv.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
return false;
}
@Override
public boolean onQueryTextChange(String currencyList) {
adapter.getFilter().filter(currencyList);
return false;
}
});
}
}
}
提前致谢：）
答案 0 :(得分：1)
使您的BaseAdapder实现Fildingrable 然后添加
List<HashMap<String,String>> mOriginalValues;
之后
ArrayList<HashMap<String,String>> currencyList;
然后在结束括号之前在底部添加此方法＆＃34;}＆＃34;
@Override
public Filter getFilter() {
Filter filter = new Filter() {
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
currencyList = (ArrayList<HashMap<String,String>>) results.values;
notifyDataSetChanged();
}
@Override
protected FilterResults performFiltering(CharSequence constraint) {
FilterResults results = new FilterResults();
ArrayList<HashMap<String, String>> FilteredArrList = new ArrayList<HashMap<String, String>>();
if (mOriginalValues == null) {
mOriginalValues = new ArrayList<HashMap<String, String>>(currencyList); // saves
}
if (constraint == null || constraint.length() == 0) {
// set the Original result to return
results.count = mOriginalValues.size();
results.values = mOriginalValues;
} else {
Locale locale = Locale.getDefault();
constraint = constraint.toString().toLowerCase(locale);
for (int i = 0; i < mOriginalValues.size(); i++) {
HashMap<String, String> currency = mOriginalValues.get(i);
String data = currency.get("name");
if (data.toLowerCase(locale).startsWith(constraint.toString())) {
FilteredArrList.add(currency);
}
}
// set the Filtered result to return
results.count = FilteredArrList.size();
results.values = FilteredArrList;
}
return results;
}
};
return filter;
}
如果有帮助，请告诉我