我试图实现从支持库的SearchView。我想让用户使用SearchView来过滤一个RecyclerView中的电影列表。
到目前为止，我已经遵循了一些教程，我已经添加了搜索视图到动作栏，但我真的不确定从这里去哪里。我看过一些例子，但没有一个在你开始输入时显示结果。
这是MainActivity:
public class MainActivity extends ActionBarActivity {
RecyclerView mRecyclerView;
RecyclerView.LayoutManager mLayoutManager;
RecyclerView.Adapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_view);
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new CardAdapter() {
@Override
public Filter getFilter() {
return null;
}
};
mRecyclerView.setAdapter(mAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
SearchView searchView = (SearchView) menu.findItem(R.id.menu_search).getActionView();
searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
这是我的适配器:
public abstract class CardAdapter extends RecyclerView.Adapter<CardAdapter.ViewHolder> implements Filterable {
List<Movie> mItems;
public CardAdapter() {
super();
mItems = new ArrayList<Movie>();
Movie movie = new Movie();
movie.setName("Spiderman");
movie.setRating("92");
mItems.add(movie);
movie = new Movie();
movie.setName("Doom 3");
movie.setRating("91");
mItems.add(movie);
movie = new Movie();
movie.setName("Transformers");
movie.setRating("88");
mItems.add(movie);
movie = new Movie();
movie.setName("Transformers 2");
movie.setRating("87");
mItems.add(movie);
movie = new Movie();
movie.setName("Transformers 3");
movie.setRating("86");
mItems.add(movie);
movie = new Movie();
movie.setName("Noah");
movie.setRating("86");
mItems.add(movie);
movie = new Movie();
movie.setName("Ironman");
movie.setRating("86");
mItems.add(movie);
movie = new Movie();
movie.setName("Ironman 2");
movie.setRating("86");
mItems.add(movie);
movie = new Movie();
movie.setName("Ironman 3");
movie.setRating("86");
mItems.add(movie);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recycler_view_card_item, viewGroup, false);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
Movie movie = mItems.get(i);
viewHolder.tvMovie.setText(movie.getName());
viewHolder.tvMovieRating.setText(movie.getRating());
}
@Override
public int getItemCount() {
return mItems.size();
}
class ViewHolder extends RecyclerView.ViewHolder{
public TextView tvMovie;
public TextView tvMovieRating;
public ViewHolder(View itemView) {
super(itemView);
tvMovie = (TextView)itemView.findViewById(R.id.movieName);
tvMovieRating = (TextView)itemView.findViewById(R.id.movieRating);
}
}
}
简单地创建两个列表在适配器一个原始和一个临时和实现可过滤。
@Override
public Filter getFilter() {
return new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
final FilterResults oReturn = new FilterResults();
final ArrayList<T> results = new ArrayList<>();
if (origList == null)
origList = new ArrayList<>(itemList);
if (constraint != null && constraint.length() > 0) {
if (origList != null && origList.size() > 0) {
for (final T cd : origList) {
if (cd.getAttributeToSearch().toLowerCase()
.contains(constraint.toString().toLowerCase()))
results.add(cd);
}
}
oReturn.values = results;
oReturn.count = results.size();//newly Aded by ZA
} else {
oReturn.values = origList;
oReturn.count = origList.size();//newly added by ZA
}
return oReturn;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(final CharSequence constraint,
FilterResults results) {
itemList = new ArrayList<>((ArrayList<T>) results.values);
// FIXME: 8/16/2017 implement Comparable with sort below
///Collections.sort(itemList);
notifyDataSetChanged();
}
};
}
在哪里
public GenericBaseAdapter(Context mContext, List<T> itemList) {
this.mContext = mContext;
this.itemList = itemList;
this.origList = itemList;
}
通过使用LiveData的Android架构组件，这可以很容易地实现任何类型的适配器。你只需要做以下步骤:
1. 设置从房间数据库返回的数据为LiveData，如下例所示:
@Dao
public interface CustomDAO{
@Query("SELECT * FROM words_table WHERE column LIKE :searchquery")
public LiveData<List<Word>> searchFor(String searchquery);
}
2. 创建一个ViewModel对象，通过连接DAO和UI的方法实时更新数据
public class CustomViewModel extends AndroidViewModel {
private final AppDatabase mAppDatabase;
public WordListViewModel(@NonNull Application application) {
super(application);
this.mAppDatabase = AppDatabase.getInstance(application.getApplicationContext());
}
public LiveData<List<Word>> searchQuery(String query) {
return mAppDatabase.mWordDAO().searchFor(query);
}
}
3.调用你的数据从ViewModel通过传入查询通过onQueryTextListener如下:
在onCreateOptionsMenu内部设置监听器，如下所示
searchView.setOnQueryTextListener(onQueryTextListener);
在SearchActivity类的某处设置查询侦听器，如下所示
private android.support.v7.widget.SearchView.OnQueryTextListener onQueryTextListener =
new android.support.v7.widget.SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
getResults(query);
return true;
}
@Override
public boolean onQueryTextChange(String newText) {
getResults(newText);
return true;
}
private void getResults(String newText) {
String queryText = "%" + newText + "%";
mCustomViewModel.searchQuery(queryText).observe(
SearchResultsActivity.this, new Observer<List<Word>>() {
@Override
public void onChanged(@Nullable List<Word> words) {
if (words == null) return;
searchAdapter.submitList(words);
}
});
}
};
注意:步骤(1.)和(2.)是标准的AAC ViewModel和DAO实现，这里唯一真正的“魔法”发生在OnQueryTextListener中，它将随着查询文本的变化动态更新列表的结果。
如果你需要更多关于此事的说明，请尽管问。
我希望这对你有所帮助:)。
我不知道为什么每个人都用两个相同的列表来解决这个问题。这使用太多内存…
为什么不只是隐藏未找到的元素，并简单地将它们的索引存储在一个Set中，以便以后能够恢复它们呢?这样内存就少多了，特别是当你的对象很大的时候。
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.SampleViewHolders>{
private List<MyObject> myObjectsList; //holds the items of type MyObject
private Set<Integer> foundObjects; //holds the indices of the found items
public MyRecyclerViewAdapter(Context context, List<MyObject> myObjectsList)
{
this.myObjectsList = myObjectsList;
this.foundObjects = new HashSet<>();
//first, add all indices to the indices set
for(int i = 0; i < this.myObjectsList.size(); i++)
{
this.foundObjects.add(i);
}
}
@NonNull
@Override
public SampleViewHolders onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View layoutView = LayoutInflater.from(parent.getContext()).inflate(
R.layout.my_layout_for_staggered_grid, null);
MyRecyclerViewAdapter.SampleViewHolders rcv = new MyRecyclerViewAdapter.SampleViewHolders(layoutView);
return rcv;
}
@Override
public void onBindViewHolder(@NonNull SampleViewHolders holder, int position)
{
//look for object in O(1) in the indices set
if(!foundObjects.contains(position))
{
//object not found => hide it.
holder.hideLayout();
return;
}
else
{
//object found => show it.
holder.showLayout();
}
//holder.imgImageView.setImageResource(...)
//holder.nameTextView.setText(...)
}
@Override
public int getItemCount() {
return myObjectsList.size();
}
public void findObject(String text)
{
//look for "text" in the objects list
for(int i = 0; i < myObjectsList.size(); i++)
{
//if it's empty text, we want all objects, so just add it to the set.
if(text.length() == 0)
{
foundObjects.add(i);
}
else
{
//otherwise check if it meets your search criteria and add it or remove it accordingly
if (myObjectsList.get(i).getName().toLowerCase().contains(text.toLowerCase()))
{
foundObjects.add(i);
}
else
{
foundObjects.remove(i);
}
}
}
notifyDataSetChanged();
}
public class SampleViewHolders extends RecyclerView.ViewHolder implements View.OnClickListener
{
public ImageView imgImageView;
public TextView nameTextView;
private final CardView layout;
private final CardView.LayoutParams hiddenLayoutParams;
private final CardView.LayoutParams shownLayoutParams;
public SampleViewHolders(View itemView)
{
super(itemView);
itemView.setOnClickListener(this);
imgImageView = (ImageView) itemView.findViewById(R.id.some_image_view);
nameTextView = (TextView) itemView.findViewById(R.id.display_name_textview);
layout = itemView.findViewById(R.id.card_view); //card_view is the id of my androidx.cardview.widget.CardView in my xml layout
//prepare hidden layout params with height = 0, and visible layout params for later - see hideLayout() and showLayout()
hiddenLayoutParams = new CardView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
hiddenLayoutParams.height = 0;
shownLayoutParams = new CardView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
}
@Override
public void onClick(View view)
{
//implement...
}
private void hideLayout() {
//hide the layout
layout.setLayoutParams(hiddenLayoutParams);
}
private void showLayout() {
//show the layout
layout.setLayoutParams(shownLayoutParams);
}
}
}
我只是有一个EditText作为我的搜索框:
cardsSearchTextView.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void afterTextChanged(Editable editable) {
myViewAdapter.findObject(editable.toString().toLowerCase());
}
});
结果:
这是我对扩展@klimat答案不丢失过滤动画的看法。
public void filter(String query){
int completeListIndex = 0;
int filteredListIndex = 0;
while (completeListIndex < completeList.size()){
Movie item = completeList.get(completeListIndex);
if(item.getName().toLowerCase().contains(query)){
if(filteredListIndex < filteredList.size()) {
Movie filter = filteredList.get(filteredListIndex);
if (!item.getName().equals(filter.getName())) {
filteredList.add(filteredListIndex, item);
notifyItemInserted(filteredListIndex);
}
}else{
filteredList.add(filteredListIndex, item);
notifyItemInserted(filteredListIndex);
}
filteredListIndex++;
}
else if(filteredListIndex < filteredList.size()){
Movie filter = filteredList.get(filteredListIndex);
if (item.getName().equals(filter.getName())) {
filteredList.remove(filteredListIndex);
notifyItemRemoved(filteredListIndex);
}
}
completeListIndex++;
}
}
基本上，它所做的就是查看一个完整的列表，并逐个向过滤后的列表添加/删除项。
