java - 在操作栏上搜索 ListView 项目

Question

你好我是android studio的新手。我想在不使用数据库的情况下搜索操作栏上的 ListView 项目。目前我的代码只显示带有多行文本的ListView。你能帮助我使用搜索小部件而不是 editText 来实现这一点吗？

Answer 1

<强>1。添加搜索菜单

创建一个带有搜索菜单项的菜单资源文件(当点击搜索菜单项时，搜索小部件将出现在操作栏中)。
以下是我创建的示例菜单资源 (res/menu/search_menu.xml)

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/search"
        android:title="Search"
        android:icon="@drawable/search"
        android:showAsAction="collapseActionView|ifRoom"
        android:actionViewClass="android.widget.SearchView" />
</menu>

在上面的菜单项中，collapseActionView 属性允许您的 SearchView 扩展以占据整个操作栏，并在不使用时折叠回正常的操作栏项

<强>2。创建 SearchableConfiguration

可搜索配置定义 SearchView 的行为方式
需要在 xml(res/xml/searchable.xml) 中定义它。以下是一个可搜索的配置文件示例

<?xml version="1.0" encoding="utf-8"?>
<searchable
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:label="@string/app_name"
    android:hint="Search friend">
</searchable>

然后将此元素添加到带有标签的相关 Activity 中

<activity
    android:name=".ui.FriendListActivity"
    android:screenOrientation="portrait"
    android:configChanges="orientation"
    android:theme="@style/Theme.Yello"
    android:windowSoftInputMode="stateHidden"
    android:launchMode="singleTask"
    android:parentActivityName=".ui.SensorDetailsActivity">
    <meta-data
        android:name="android.app.searchable"
        android:resource="@xml/searchable">
    </meta-data>
</activity>

在我的场景中，我要将 SearchView 添加到 FriendListActivity

<强>3。添加菜单和 SearchableConfiguration 到 Activity

将可搜索配置与 Activity 类中的 SearchView 相关联

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.search_menu, menu);

    SearchManager searchManager = (SearchManager)
                            getSystemService(Context.SEARCH_SERVICE);
    searchMenuItem = menu.findItem(R.id.search);
    searchView = (SearchView) searchMenuItem.getActionView();

    searchView.setSearchableInfo(searchManager.
                            getSearchableInfo(getComponentName()));
    searchView.setSubmitButtonEnabled(true);
    searchView.setOnQueryTextListener(this);

    return true;
}

现在 SearchView 添加到 Activity 中。但搜索功能仍然不起作用

<强>4。添加搜索功能

在activity中实现SearchView.OnQueryTextListener，现在需要覆盖两个新方法

public boolean onQueryTextSubmit(String query)
public boolean onQueryTextChange(String newText)

该接口(interface)监听SearchView中的文本变化事件

@Override
public boolean onQueryTextSubmit(String query) {
    return false;
}

@Override
public boolean onQueryTextChange(String newText) {
    friendListAdapter.getFilter().filter(newText);

    return true;
}

这里的 onQueryTextChange 函数使用列表适配器进行过滤，为了进行过滤，适配器需要实现 Filterable 接口(interface)

4.可过滤适配器

在我的场景中，我使用了 BaseAdapter 来实现 Filterable 接口(interface)
以下是我的适配器类(FriendListAdapter)的实现

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.*;
import com.score.senzors.R;
import com.score.senzors.pojos.User;

import java.util.ArrayList;

/**
 * Display friend list
 *
 */
public class FriendListAdapter extends BaseAdapter implements Filterable {
private FriendListActivity activity;
private FriendFilter friendFilter;
private Typeface typeface;
private ArrayList<User> friendList;
private ArrayList<User> filteredList;

/**
 * Initialize context variables
 * @param activity friend list activity
 * @param friendList friend list
 */
public FriendListAdapter(FriendListActivity activity, ArrayList<User> friendList) {
    this.activity = activity;
    this.friendList = friendList;
    this.filteredList = friendList;
    typeface = Typeface.createFromAsset(activity.getAssets(), "fonts/vegur_2.otf");

    getFilter();
}

/**
 * Get size of user list
 * @return userList size
 */
@Override
public int getCount() {
    return filteredList.size();
}

/**
 * Get specific item from user list
 * @param i item index
 * @return list item
 */
@Override
public Object getItem(int i) {
    return filteredList.get(i);
}

/**
 * Get user list item id
 * @param i item index
 * @return current item id
 */
@Override
public long getItemId(int i) {
    return i;
}

/**
 * Create list row view
 * @param position index
 * @param view current list item view
 * @param parent parent
 * @return view
 */
@Override
public View getView(int position, View view, ViewGroup parent) {
    // A ViewHolder keeps references to children views to avoid unnecessary calls
    // to findViewById() on each row.
    final ViewHolder holder;
    final User user = (User) getItem(position);

    if (view == null) {
        LayoutInflater layoutInflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = layoutInflater.inflate(R.layout.friend_list_row_layout, parent, false);
        holder = new ViewHolder();
        holder.iconText = (TextView) view.findViewById(R.id.icon_text);
        holder.name = (TextView) view.findViewById(R.id.friend_list_row_layout_name);
        holder.iconText.setTypeface(typeface, Typeface.BOLD);
        holder.iconText.setTextColor(activity.getResources().getColor(R.color.white));
        holder.name.setTypeface(typeface, Typeface.NORMAL);

        view.setTag(holder);
    } else {
        // get view holder back
        holder = (ViewHolder) view.getTag();
    }

    // bind text with view holder content view for efficient use
    holder.iconText.setText("#");
    holder.name.setText(user.getEmail());
    view.setBackgroundResource(R.drawable.friend_list_selector);

    return view;
}

/**
 * Get custom filter
 * @return filter
 */
@Override
public Filter getFilter() {
    if (friendFilter == null) {
        friendFilter = new FriendFilter();
    }

    return friendFilter;
}

/**
 * Keep reference to children view to avoid unnecessary calls
 */
static class ViewHolder {
    TextView iconText;
    TextView name;
}

/**
 * Custom filter for friend list
 * Filter content in friend list according to the search text
 */
private class FriendFilter extends Filter {

    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
        FilterResults filterResults = new FilterResults();
        if (constraint!=null && constraint.length()>0) {
            ArrayList<User> tempList = new ArrayList<User>();

            // search content in friend list
            for (User user : friendList) {
                if (user.getEmail().toLowerCase().contains(constraint.toString().toLowerCase())) {
                    tempList.add(user);
                }
            }

            filterResults.count = tempList.size();
            filterResults.values = tempList;
        } else {
            filterResults.count = friendList.size();
            filterResults.values = friendList;
        }

        return filterResults;
    }

    /**
     * Notify about filtered list to ui
     * @param constraint text
     * @param results filtered result
     */
    @SuppressWarnings("unchecked")
    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {
        filteredList = (ArrayList<User>) results.values;
        notifyDataSetChanged();
    }
}

}

在这里我定义了自定义过滤器类 FriendFilter 来进行过滤，我根据在 SearchView 中输入的名称过滤列表