android - 如何在 BaseAdapter 中使用 getFilter() 过滤 ListView

Question

在我的应用程序中，我创建了一个自定义 ListView ，我想实现一个过滤器，以便可以根据在 EditText 中输入的文本来过滤列表。我将 BaseAdapter 用作单独的类，并在我的主 Activity 中调用该类。我还在我的主要 Activity 中实现了 addTextChangedListener() 并且还在我的 BaseAdapter 类中实现了 getFilter() 。但我不知道如何使用 getFilter() 并相应地过滤我的列表。在列表中，我添加了来自 JSON URL 的值。请帮助我让我知道如何使用 getFilter() 来过滤我的列表。

Activity类代码:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    lv = (ListView)findViewById(R.id.listView1);
    et1 = (EditText)findViewById(R.id.editText1);
    inflator = getLayoutInflater();
    et1.addTextChangedListener(this);
    JsonParser jParser = new JsonParser();
    JSONObject json = jParser.getJSONfromUrl(url);
    try
    {
        JSONArray explore = json.getJSONArray("explore");
        for(int i=0; i<explore.length(); i++)
        {
            JSONObject exp = explore.getJSONObject(i);
            list.add(exp.getString("username"));
        }
    }
    catch(JSONException e)
    {
        e.printStackTrace();
    }

    srchadptr = new SearchAdapter(this, inflator, list);
    lv.setAdapter(srchadptr);
}

public void afterTextChanged(Editable s) {
    // TODO Auto-generated method stub
    srchadptr.getFilter().filter(s);
}

public void beforeTextChanged(CharSequence s, int start, int count,
        int after) {
    // TODO Auto-generated method stub

}

public void onTextChanged(CharSequence s, int start, int before, int count) {
    // TODO Auto-generated method stub

}

BaseAdapter类代码:

public class SearchAdapter extends BaseAdapter implements Filterable {

    Context context;
    LayoutInflater inflater;
    Button btn;
    View vw;
    ArrayList<String> list = new ArrayList<String>();

    public SearchAdapter(Context context,   LayoutInflater inflater, ArrayList<String> list) {
        // TODO Auto-generated constructor stub
        this.context = context;
        this.inflater = inflater;
        this.list = list;
    }

    /*public CharSequence filter(CharSequence cs) {
        return cs;
    }*/

    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }



    public View getView(final int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        LinearLayout ll = (LinearLayout) vw;
        final EditText edt = ((EditText)ll.getChildAt(0));
        vw = inflater.inflate(R.layout.list_items, null);
        ImageView img = (ImageView)vw.findViewById(R.id.imageView1);
        TextView tv = (TextView)vw.findViewById(R.id.textView1);
        btn = (Button)vw.findViewById(R.id.button1);
        tv.setText(String.valueOf(list.get(position)));
        btn.setText(String.valueOf(list.get(position)));
        btn.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                Toast.makeText(context, list.get(position), Toast.LENGTH_LONG).show();
            }
        });
        return vw;
    }

    public android.widget.Filter getFilter() {
        // TODO Auto-generated method stub
        return new android.widget.Filter() {

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                // TODO Auto-generated method stub

            }

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                // TODO Auto-generated method stub
                return null;
            }
        };
    }
}

提前致谢...

Answer 1

希望这个例子能帮到你

在 Main_Activity 中

    EditText etSearch;
    BaseAdapterFilterable adapter;

    etSearch.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                // Listview name of the class
                Listview.this.adapter.getFilter().filter(s);
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {
                // TODO Auto-generated method stub

            }

            @Override
            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub

            }
        });

在你的适配器中放入这个类以在 getfilter 方法中使用它

public class filter_here extends Filter{

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            // TODO Auto-generated method stub

            FilterResults Result = new FilterResults();
            // if constraint is empty return the original names
            if(constraint.length() == 0 ){
                Result.values = Original_Names;
                Result.count = Original_Names.size();
                return Result;
            }

            ArrayList<String> Filtered_Names = new ArrayList<String>();
            String filterString = constraint.toString().toLowerCase();
            String filterableString;

            for(int i = 0; i<Original_Names.size(); i++){
                filterableString = Original_Names.get(i);
                if(filterableString.toLowerCase().contains(filterString)){
                    Filtered_Names.add(filterableString);
                }
            }
            Result.values = Filtered_Names;
            Result.count = Filtered_Names.size();

            return Result;
        }

        @Override
        protected void publishResults(CharSequence constraint,FilterResults results) {
            // TODO Auto-generated method stub
            Names = (ArrayList<String>) results.values;
            notifyDataSetChanged();
        }

    }

同样在你的适配器中从filter_here类返回实例

@Override
    public Filter getFilter() {
        // TODO Auto-generated method stub
        return filter;
    }