使用自定义(对象)适配器过滤 ListView [英] Filtering ListView with custom (object) adapter

问题描述

我正在尝试对使用自定义对象适配器的 ListView 进行过滤，但我找不到任何有用的示例.包含的代码非常简化，所以不要记住我不能使用常规的 ArrayAdapter.我在 ListView 上方有一个 EditText，当用户在 EditText 小部件中输入文本时，我想通过 EditText 中写入的文本过滤 ListView.任何建议将不胜感激！

I'm trying to implement filtering of a ListView which is uses a custom object adapter, but I can't find any useful samples. The included code is very simplified, so no- keep in mind I can't use an regular ArrayAdapter. I have a EditText above the ListView, and when the user enters text in the EditText widget I would like to filter the ListView by the text written in the EditText. Any suggestions would be much appreciated!

这是活动类的片段:

public class management_objects extends Activity {

private static List<User> UserList;
private EfficientAdapter adapter = null;
private ListView objectListView = null;
private EditText SearchText = null;

private static class EfficientAdapter extends BaseAdapter implements Filterable{
    private LayoutInflater mInflater;   

    public EfficientAdapter(Context context) {
        mInflater = LayoutInflater.from(context);
    }

    public int getCount() {
        return UserList.size();
    }

    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder; 
        if (convertView == null) { 
            convertView = mInflater.inflate(R.layout.imagelayout_2lines, null);
            holder = new ViewHolder();
            holder.text = (TextView) convertView.findViewById(R.id.managementObjectText);
            holder.subtext = (TextView) convertView.findViewById(R.id.managementObjectSubText);
            holder.icon = (ImageView) convertView.findViewById(R.id.managementObjectIcon);
            convertView.setTag(holder);
        }
        else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.text.setText(UserList.get(position).getFirstName());
        holder.subtext.setText(UserList.get(position).getLastName());
        holder.icon.setImageResource(R.drawable.user);

        return convertView;
    }

    static class ViewHolder { 
        TextView text;
        TextView subtext;
        ImageView icon;
    }

    @Override
    public Filter getFilter() {
        return null;
    }
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.adobjectlist);
    Bundle extras = getIntent().getExtras();

    SearchText = (EditText) findViewById(R.id.SearchBox);    
    SearchText.addTextChangedListener(filterTextWatcher);

    objectListView = (ListView) findViewById(R.id.ObjectList);
    objectListView.setOnItemClickListener(Item_Click);
    adapter = new EfficientAdapter(this);
    ComputerName = extras.getString("COMPUTER_NAME");

    //Get User list from webservice
    ShowUsers();
}

这是用户类:

 public class User {
  private int UserId;
  private String FirstName;
  private String LastName;

    public int getUserId() {
        return UserId;
    }
    public void setUserId(int UserId) {
        this.UserId = UserId;
    }
    public String getFirstName() {
        return FirstName;
    }
    public void setFirstName(String FirstName) {
        this.FirstName = FirstName;
    }
    public String getLastName() {
        return LastName;
    }
    public void setLastName(String LastName) {
        this.LastName = LastName;
    }
}

推荐答案

你需要做的几件事:

1) 在您的活动中，在包含用户输入的值的 EditText 上注册文本更改侦听器:

1) In your activity, register for a text change listener on your EditText that contains the value the user enters:

mSearchValue.addTextChangedListener(searchTextWatcher);

mSearchValue.addTextChangedListener(searchTextWatcher);

2) 创建您的 searchTextWatcher 并让它做一些事情:

2) Create your searchTextWatcher and have it do something:

private TextWatcher searchTextWatcher = new TextWatcher() {
    @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            // ignore
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            // ignore
        }

        @Override
        public void afterTextChanged(Editable s) {
            Log.d(Constants.TAG, "*** Search value changed: " + s.toString());
            adapter.getFilter().filter(s.toString());
        }
    };

3) 在您的自定义适配器中覆盖 getFilter() 并让它过滤结果并通知列表视图数据集已更改.

3) Override getFilter() in your custom adapter and have it filter the results and notify the listview that the dataset has changed.

    @Override
    public Filter getFilter() {
        return new Filter() {
            @SuppressWarnings("unchecked")
            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                Log.d(Constants.TAG, "**** PUBLISHING RESULTS for: " + constraint);
                myData = (List<MyDataType>) results.values;
                MyCustomAdapter.this.notifyDataSetChanged();
            }

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                Log.d(Constants.TAG, "**** PERFORM FILTERING for: " + constraint);
                List<MyDataType> filteredResults = getFilteredResults(constraint);

                FilterResults results = new FilterResults();
                results.values = filteredResults;

                return results;
            }
        };
    }

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