List View Filter Android

问题:

I have created a list view in android and I want to add edit text above the list and when the user enter text the list will be filtered according to user input

can anyone tell me please if there is a way to filter the list adapter in android ?

回答1:

Yes. Add an EditText on top of your listview in its aml layout file. And in your activity/fragment..

lv = (ListView) findViewById(R.id.list_view);     inputSearch = (EditText) findViewById(R.id.inputSearch);  // Adding items to listview adapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.product_name,    products); lv.setAdapter(adapter);        inputSearch.addTextChangedListener(new TextWatcher() {      @Override     public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {         // When user changed the Text         MainActivity.this.adapter.getFilter().filter(cs);     }      @Override     public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) { }      @Override     public void afterTextChanged(Editable arg0) {} }); 

The basic here is to add an OnTextChangeListener to your edit text and inside its callback method apply filter to your listview's adapter.

EDIT

To get filter to your custom BaseAdapter you"ll need to implement Filterable interface.

class CustomAdapter extends BaseAdapter implements Filterable {      public View getView(){     ...     }     public Integer getCount()     {     ...     }      @Override     public Filter getFilter() {          Filter filter = new Filter() {              @SuppressWarnings("unchecked")             @Override             protected void publishResults(CharSequence constraint, FilterResults results) {                  arrayListNames = (List<String>) results.values;                 notifyDataSetChanged();             }              @Override             protected FilterResults performFiltering(CharSequence constraint) {                  FilterResults results = new FilterResults();                 ArrayList<String> FilteredArrayNames = new ArrayList<String>();                  // perform your search here using the searchConstraint String.                  constraint = constraint.toString().toLowerCase();                 for (int i = 0; i < mDatabaseOfNames.size(); i++) {                     String dataNames = mDatabaseOfNames.get(i);                     if (dataNames.toLowerCase().startsWith(constraint.toString()))  {                         FilteredArrayNames.add(dataNames);                     }                 }                  results.count = FilteredArrayNames.size();                 results.values = FilteredArrayNames;                 Log.e("VALUES", results.values.toString());                  return results;             }         };          return filter;     } } 

Inside perfromFiltering() you need to do actual comparison of the search query to values in your database. It will pass its result to publishResults() method.

回答2:

Implement your adapter Filterable:

public class vJournalAdapter extends ArrayAdapter<JournalModel> implements Filterable{ private ArrayList<JournalModel> items; private Context mContext; .... 

then create your Filter class:

private class JournalFilter extends Filter{      @Override     protected FilterResults performFiltering(CharSequence constraint) {         FilterResults result = new FilterResults();         List<JournalModel> allJournals = getAllJournals();         if(constraint == null || constraint.length() == 0){              result.values = allJournals;             result.count = allJournals.size();         }else{             ArrayList<JournalModel> filteredList = new ArrayList<JournalModel>();             for(JournalModel j: allJournals){                 if(j.source.title.contains(constraint))                     filteredList.add(j);             }             result.values = filteredList;             result.count = filteredList.size();         }          return result;     }     @SuppressWarnings("unchecked")     @Override     protected void publishResults(CharSequence constraint, FilterResults results) {         if (results.count == 0) {             notifyDataSetInvalidated();         } else {             items = (ArrayList<JournalModel>) results.values;             notifyDataSetChanged();         }     }  } 

this way, your adapter is Filterable, you can pass filter item to adapter's filter and do the work. I hope this will be helpful.

回答3:

In case anyone are still interested in this subject, I find that the best approach for filtering lists is to create a generic Filter class and use it with some base reflection/generics techniques contained in the Java old school SDK package. Here's what I did:

public class GenericListFilter<T> extends Filter {      /**      * Copycat constructor      * @param list  the original list to be used      */     public GenericListFilter (List<T> list, String reflectMethodName, ArrayAdapter<T> adapter) {         super ();          mInternalList = new ArrayList<>(list);         mAdapterUsed  = adapter;          try {             ParameterizedType stringListType = (ParameterizedType)                     getClass().getField("mInternalList").getGenericType();             mCompairMethod =                     stringListType.getActualTypeArguments()[0].getClass().getMethod(reflectMethodName);         }         catch (Exception ex) {             Log.w("GenericListFilter", ex.getMessage(), ex);              try {                 if (mInternalList.size() > 0) {                     T type = mInternalList.get(0);                     mCompairMethod = type.getClass().getMethod(reflectMethodName);                 }             }             catch (Exception e) {                 Log.e("GenericListFilter", e.getMessage(), e);             }          }     }      /**      * Let's filter the data with the given constraint      * @param constraint      * @return      */     @Override protected FilterResults performFiltering(CharSequence constraint) {         FilterResults results = new FilterResults();         List<T> filteredContents = new ArrayList<>();          if ( constraint.length() > 0 ) {             try {                 for (T obj : mInternalList) {                     String result = (String) mCompairMethod.invoke(obj);                     if (result.toLowerCase().startsWith(constraint.toString().toLowerCase())) {                         filteredContents.add(obj);                     }                 }             }             catch (Exception ex) {                 Log.e("GenericListFilter", ex.getMessage(), ex);             }         }         else {             filteredContents.addAll(mInternalList);         }          results.values = filteredContents;         results.count  = filteredContents.size();         return results;     }      /**      * Publish the filtering adapter list      * @param constraint      * @param results      */     @Override protected void publishResults(CharSequence constraint, FilterResults results) {         mAdapterUsed.clear();         mAdapterUsed.addAll((List<T>) results.values);          if ( results.count == 0 ) {             mAdapterUsed.notifyDataSetInvalidated();         }         else {             mAdapterUsed.notifyDataSetChanged();         }     }      // class properties     private ArrayAdapter<T> mAdapterUsed;     private List<T> mInternalList;     private Method  mCompairMethod; } 

And afterwards, the only thing you need to do is to create the filter as a member class (possibly within the View's "onCreate") passing your adapter reference, your list, and the method to be called for filtering:

this.mFilter = new GenericFilter<MyObjectBean> (list, "getName", adapter); 

The only thing missing now, is to override the "getFilter" method in the adapter class:

@Override public Filter getFilter () {      return MyViewClass.this.mFilter; } 

All done! You should successfully filter your list - Of course, you should also implement your filter algorithm the best way that describes your need, the code bellow is just an example.. Hope it helped, take care.

文章来源: List View Filter Android