要实现模糊查询,在ListView中,你需要使用一个适配器来管理数据,并且根据输入的查询条件动态过滤数据。
以下是一个简单的实现模糊查询的示例:
下面是一个简单的示例代码:
public class MainActivity extends AppCompatActivity {
private ListView listView;
private EditText editText;
private CustomAdapter adapter;
private List<String> dataList;
private List<String> filteredDataList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = findViewById(R.id.listView);
editText = findViewById(R.id.editText);
// 初始化数据列表
dataList = new ArrayList<>();
dataList.add("Apple");
dataList.add("Banana");
dataList.add("Cherry");
dataList.add("Grape");
dataList.add("Lemon");
dataList.add("Orange");
dataList.add("Peach");
dataList.add("Strawberry");
dataList.add("Watermelon");
filteredDataList = new ArrayList<>();
filteredDataList.addAll(dataList);
// 创建适配器并绑定数据
adapter = new CustomAdapter();
listView.setAdapter(adapter);
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) {
// 根据输入的查询条件进行过滤
adapter.getFilter().filter(s);
}
@Override
public void afterTextChanged(Editable s) {}
});
}
private class CustomAdapter extends BaseAdapter implements Filterable {
private Filter filter;
@Override
public int getCount() {
return filteredDataList.size();
}
@Override
public Object getItem(int position) {
return filteredDataList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(MainActivity.this).inflate(android.R.layout.simple_list_item_1, parent, false);
}
TextView textView = convertView.findViewById(android.R.id.text1);
textView.setText(filteredDataList.get(position));
return convertView;
}
@Override
public Filter getFilter() {
if (filter == null) {
filter = new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
FilterResults results = new FilterResults();
List<String> filteredList = new ArrayList<>();
if (TextUtils.isEmpty(constraint)) {
filteredList.addAll(dataList);
} else {
String filterPattern = constraint.toString().toLowerCase().trim();
for (String item : dataList) {
if (item.toLowerCase().contains(filterPattern)) {
filteredList.add(item);
}
}
}
results.values = filteredList;
results.count = filteredList.size();
return results;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
filteredDataList.clear();
filteredDataList.addAll((List<String>) results.values);
notifyDataSetChanged();
}
};
}
return filter;
}
}
}
在上述代码中,用户每次输入查询条件时,都会触发EditText的onTextChanged()方法,然后通过调用适配器的getFilter().filter(s)方法来执行过滤操作。过滤结果会更新到适配器的filteredDataList列表中,并调用适配器的notifyDataSetChanged()方法刷新ListView。