我有这个代码工作正常，在listview上显示我的产品。现在我正在尝试在操作栏上实现搜索。
我有一个CustomListAdapter，我正在读这个How to implement getfilter()...
我更改了我的CustomListADapter，以便在我在搜索操作栏上输入时显示结果。我在输入时遇到异常：
09-02 15:45:17.153: I/System.out(2135): on text chnge text: Tec
09-02 15:45:17.205: W/Filter(2135): An exception occured during performFiltering()!
09-02 15:45:17.205: W/Filter(2135): java.lang.NullPointerException
09-02 15:45:17.205: W/Filter(2135): at com.habitodigital.products.adapter.CustomListAdapter$1.performFiltering(CustomListAdapter.java:131)
09-02 15:45:17.205: W/Filter(2135): at android.widget.Filter$RequestHandler.handleMessage(Filter.java:234)
09-02 15:45:17.205: W/Filter(2135): at android.os.Handler.dispatchMessage(Handler.java:102)
09-02 15:45:17.205: W/Filter(2135): at android.os.Looper.loop(Looper.java:136)
09-02 15:45:17.205: W/Filter(2135): at android.os.HandlerThread.run(HandlerThread.java:61)
CustomListAdapter.java
public class CustomListAdapter extends BaseAdapter implements Filterable {
public ImageView thumbNail;
TextView p_id, name;
DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
.showImageOnFail(R.drawable.no_image_available)
.showImageForEmptyUri(R.drawable.no_image_available)
.cacheInMemory(true)
.imageScaleType(ImageScaleType.EXACTLY)
.displayer(new FadeInBitmapDisplayer(300)).build();
private Activity activity;
private LayoutInflater inflater;
private List<Product> pItems;
ImageLoader imageLoader = ImageLoader.getInstance();
private ArrayList<HashMap<String, String>> originalData;
private ArrayList<HashMap<String, String>> filteredData;
public CustomListAdapter(Activity activity, List<Product> pItems) {
this.activity = activity;
this.pItems = pItems;
}
@Override
public int getCount() {
return pItems.size();
}
@Override
public Object getItem(int location) {
return pItems.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_row, null);
p_id = (TextView) convertView.findViewById(R.id.p_id);
thumbNail = (ImageView) convertView
.findViewById(R.id.thumbnail);
name = (TextView) convertView.findViewById(R.id.name);
Product m = pItems.get(position);
p_id.setText(m.getP_id());
String url = m.getThumbnailUrl();
Picasso.with(activity).load(url).resize(80, 80).centerCrop().into(thumbNail);
thumbNail.setTag(url);
name.setText(m.getName());
return convertView;
}
@Override
public Filter getFilter() {
return new Filter(){
@Override
protected FilterResults performFiltering(CharSequence charSequence){
FilterResults results = new FilterResults();
/* if nothing to filter, return original list results */
if(charSequence == null || charSequence.length() == 0){
results.values = originalData;
results.count = originalData.size();
}else{
ArrayList<HashMap<String, String>> filterResultsData = new ArrayList<HashMap<String,String>>();
for(HashMap<String, String> data : originalData){
if(charSequence == originalData){
filterResultsData.add(data);
}
}
results.values = filterResultsData;
results.count = filterResultsData.size();
}
return results;
}
@Override
protected void publishResults(CharSequence charSequence,
FilterResults results) {
filteredData = (ArrayList<HashMap<String,String>>) results.values;
notifyDataSetChanged();
}
};
}
}
ListView活动：
public class ListProducts extends Activity {
TextView state, t_city, noProduct;
String city = "", statee = "";
ImageButton newSch;
// Log tag
private static final String TAG = ListProducts.class.getSimpleName();
private static final String url = "http://mywebsite.com/json.php";
private List<Product> pList = new ArrayList<Product>();
private ListView listView;
private CustomListAdapter adapter;
private static final String TAG_PID = "p_id";
private static final String TAG_ARQUIVO = "file";
private static final String TAG_NAME = "name";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_products);
handleIntent(getIntent());
state = (TextView) findViewById(R.id.State);
t_city = (TextView) findViewById(R.id.City);
noProduct = (TextView) findViewById(R.id.noProduct);
newSch = (ImageButton) findViewById(R.id.newSch);
state.setText(getIntent().getExtras().getString("state"));
t_city.setText(getIntent().getExtras().getString("city"));
listView = (ListView) findViewById(R.id.list);
adapter = new CustomListAdapter(this, pList);
new LoadAsync().execute();
newSch.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent newS = new Intent(getApplicationContext(), SearchCity.class);
startActivity(newS);
}
});
}
public class LoadAsync extends AsyncTask<String, Boolean, Boolean>{
public ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ListProduct.this);
pDialog.setMessage("Loading...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected Boolean doInBackground(String... params) {
// Creating volley request obj
JsonArrayRequest pReq = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
pDialog.dismiss();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
Product product = new Product();
product.setP_id(obj.getString("p_id"));
product.setName(obj.getString("name"));
product.setThumbnailUrl(obj.getString("file"));
city = obj.getString("city");
statee = obj.getString("state");
if(state.getText().toString().equalsIgnoreCase(statee) &&
t_.getText().toString().equalsIgnoreCase(city)){
pList.add(product);
}
} catch (JSONException e) {
e.printStackTrace();
}
} if(pList.size() > 0){
listView.setAdapter(adapter);
listView.setTextFilterEnabled(true);
}else{
noP.setText("Oops! No product");
}
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
pDialog.dismiss();
}
});
AppController.getInstance().addToRequestQueue(pReq);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String pID = ((TextView) view.findViewById(R.id.p_id)).getText().toString();
ImageView pFile = ((ImageView) view.findViewById(R.id.thumbnail));
String imgUrl = (String) pFile.getTag();
String pName = ((TextView) view.findViewById(R.id.name)).getText().toString();
Intent i = new Intent(getApplicationContext(), PDetails.class);
i.putExtra(TAG_PID, pID);
i.putExtra(TAG_ARQUIVO, imgUrl);
i.putExtra(TAG_NAME, pName);
startActivity(i);
}
});
return null;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
//pDialog.dismiss();
}
}
@Override
protected void onNewIntent(Intent intent) {
handleIntent(intent);
}
private void handleIntent(Intent intent) {
if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
String query = intent.getStringExtra(SearchManager.QUERY);
//use the query to search your data somehow
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.list_products, menu);
SearchManager manager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();
searchView.setSearchableInfo(manager.getSearchableInfo(getComponentName()));
searchView.setIconifiedByDefault(false);
SearchView.OnQueryTextListener textChangeListener = new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextChange(String newText) {
adapter.getFilter().filter(newText);
System.out.println("on text chnge text: "+ newText);
return false;
}
@Override
public boolean onQueryTextSubmit(String query) {
adapter.getFilter().filter(query);
System.out.println("on query submit: "+query);
return false;
}
};
searchView.setOnQueryTextListener(textChangeListener);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
我是否正确地将它与for循环进行比较？
FilterResults results = new FilterResults();
/* if nothing to filter, return original list results */
if(charSequence == null || charSequence.length() == 0){
results.values = pItems;
results.count = pItems.size();
}else{
for(Product data : pItems){
if(charSequence == pItems){
pItems.add(data);
}
}
results.values = pItems;
results.count = pItems.size();
}
return results;
答案 0 :(得分：0)
经过一些搜索后，我将过滤器更改为
> myArray = ['a', 'b', 'c', 'd']
["a", "b", "c", "d"]
> myArray.splice(0, 2)
["a", "b"]
> myArray
["c", "d"]