在Android上,ListView的过滤器在多列上不起作用的问题可以通过自定义适配器和Filter类来解决。以下是一个解决方法的代码示例:
首先,创建一个自定义的适配器类,继承自BaseAdapter,并实现Filterable接口:
public class CustomAdapter extends BaseAdapter implements Filterable {
private List- originalData;
private List
- filteredData;
private ItemFilter itemFilter;
public CustomAdapter(List
- data) {
originalData = data;
filteredData = data;
}
@Override
public int getCount() {
return filteredData.size();
}
@Override
public Object getItem(int position) {
return filteredData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// 实现getView方法的代码
// ...
}
@Override
public Filter getFilter() {
if (itemFilter == null) {
itemFilter = new ItemFilter();
}
return itemFilter;
}
private class ItemFilter extends Filter {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
FilterResults results = new FilterResults();
if (TextUtils.isEmpty(constraint)) {
results.values = originalData;
results.count = originalData.size();
} else {
List
- filteredList = new ArrayList<>();
for (Item item : originalData) {
// 根据多列条件进行过滤
if (item.getColumn1().toLowerCase().contains(constraint.toString().toLowerCase()) ||
item.getColumn2().toLowerCase().contains(constraint.toString().toLowerCase())) {
filteredList.add(item);
}
}
results.values = filteredList;
results.count = filteredList.size();
}
return results;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
filteredData = (List
- ) results.values;
notifyDataSetChanged();
}
}
}
然后,在Activity中使用该自定义适配器和ListView,并设置过滤器:
public class MainActivity extends AppCompatActivity {
private ListView listView;
private EditText editText;
private CustomAdapter adapter;
private List- itemList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 初始化数据
itemList = new ArrayList<>();
// 添加数据项到itemList
// 初始化ListView和EditText
listView = findViewById(R.id.listView);
editText = findViewById(R.id.editText);
// 创建适配器并设置给ListView
adapter = new CustomAdapter(itemList);
listView.setAdapter(adapter);
// 设置过滤器
editText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
adapter.getFilter().filter(s.toString());
}
});
}
}
在上述代码中,自定义适配器类CustomAdapter继承了BaseAdapter并实现了Filterable接口。在适配器中,通过重写getFilter方法返回一个自定义的Filter类ItemFilter,该Filter类实现了过滤功能。在performFiltering方法中,根据多列条件进行过滤,并将过滤后的结果通过publishResults方法发布出去。在Activity中,通过设置EditText的TextWatcher监听文本变化,当文本变化时调用适配器的getFilter方法进行过滤。最后,调用notifyDataSetChanged方法更新ListView显示过滤后的数据。