Android Studio如何访问适配器类中的列表

Question

我正在尝试访问我在适配器类中创建的食谱列表，以处理可过滤的结果。无论我尝试了什么，似乎都无法将此列表纳入我需要的区域。如果有人能告诉我如何在整个类中获得此列表，我将非常高兴。

在我的适配器类中，已初始化的列表mRecipe中有1个元素(这是正确的(，但当我在适配器类的其他任何地方调用mRecipe时，它中有0个元素。这是我的活动课。

public class SearchResultActivity extends AppCompatActivity {
private static final String TAG = "SEARCH RESULTS";
private RecipeViewModel mRecipeViewModel;
public static final int NEW_WORD_ACTIVITY_REQUEST_CODE = 1;
private RecipeListAdapter mAdapter;
private RecipeDao recDao;
private List<Recipe> recipelist = new ArrayList<Recipe>();
//List of Recipes
private List<Recipe>  RecipeListFull = new LinkedList<Recipe>();
private TextView response;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_result);
mAdapter = new RecipeListAdapter(this, recipelist);
RecyclerView recyclerView = findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mRecipeViewModel = new ViewModelProvider(this).get(RecipeViewModel.class);
mRecipeViewModel.getAllRecipes().observe(this, new Observer<List<Recipe>>() {
@Override
public void onChanged(@Nullable final List<Recipe> recipeList) {
// Update the cached copy of the words in the adapter.
mAdapter.setWords(recipeList);
Log.d(TAG , "SET WORDS: " + recipeList.size());
}});
Log.d(TAG, "recipe list size: " + recipelist.size());
String query = getIntent().getStringExtra("Search");
Log.d(TAG, "Query String: " + query);
response = (TextView) findViewById(R.id.filler);
int count = 0; //Replace this somehow
response.setText(count + " Recipes were found with the query " + query);
mAdapter.getFilter().filter(query); {
}}}

这是我的适配器类

public class RecipeListAdapter extends RecyclerView.Adapter<RecipeListAdapter.RecipeViewHolder> implements Filterable {
private static final String TAG = "ADAPTER";
private OnItemClickListener mListener;
public List<Recipe> mRecipes = new ArrayList<Recipe>();
private List<Recipe> fullRecipes;
private RecipeViewModel viewModel;
public Recipe getRecipeAtPosition(int position) {
return mRecipes.get(position);
}

public interface OnItemClickListener{
void onItemClick(int position, View view);
}
public void setOnItemClickListener(OnItemClickListener listener){
mListener = listener;
}
class RecipeViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private final TextView recipeItemView;
private RecipeViewHolder(View itemView) {
super(itemView);
recipeItemView = itemView.findViewById(R.id.textView);
Log.d(TAG, "Size of Array in Adapter:" + mRecipes.size());
itemView.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v){
if (mListener != null){
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION){
mListener.onItemClick(position, v);
}
}
}
});
}
@Override
public void onClick(View view) {
mListener.onItemClick(getAdapterPosition(), view);
}
}
private final LayoutInflater mInflater;

RecipeListAdapter(Context context, List<Recipe> mRecipes) {
this.fullRecipes = mRecipes;
Log.d(TAG, "Size of Full Recipes CONSTRUCTOR: " + fullRecipes.size());
mInflater = LayoutInflater.from(context);
}
@Override
public RecipeViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = mInflater.inflate(R.layout.recyclerview_item, parent, false);
return new RecipeViewHolder(itemView);
}
@Override
public void onBindViewHolder(RecipeViewHolder holder, int position) {
if (mRecipes != null) {
Recipe current = mRecipes.get(position);
holder.recipeItemView.setText(current.getName());
} else {
// Covers the case of data not being ready yet.
holder.recipeItemView.setText("No Recipes");
}
}
void setWords(List<Recipe> recipes){
mRecipes = recipes;
notifyDataSetChanged();
}
public void deleteItem(final int position) {
mRecipes.remove(position);
notifyItemRemoved(position);
}
public void updateItem(Recipe recipe) {
mRecipes.remove(recipe);
}
public List<Recipe> getList(){
return mRecipes;
}

@Override
public int getItemCount() {
if (mRecipes != null)
return mRecipes.size();
else return 0;
}
public interface OnNoteListener{}
@Override
public Filter getFilter() {
return filter;
}
private Filter filter = new Filter(){
@Override
protected FilterResults performFiltering(CharSequence constraint) {
Log.d(TAG, "Length of fullRecipes " +fullRecipes.size());
List<Recipe> filteredList = new ArrayList<>();
Log.d(TAG, "Attempting to filter word: " + constraint);
if (constraint.length() == 0){
//Here should say 0 found
}
else {
String filterPattern = constraint.toString().toLowerCase().trim();
for (Recipe recipe : fullRecipes){
if (recipe.getName().toLowerCase().contains(filterPattern)){
filteredList.add(recipe);
Log.d(TAG, "Filtered: " + filteredList.toString());
}
}
}
FilterResults results = new FilterResults();
results.values = filteredList;
return results;
}
@Override
protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
mRecipes.clear();
mRecipes.addAll((List)filterResults.values);
Log.d(TAG, "Array Values! " + mRecipes.size());
if (mRecipes.size() == 0){
//No Matches have been found
}
else {
notifyDataSetChanged();
}
}

}；｝

Answer 1

您可以在onChanged方法中添加mAdapter.notifyDataSetChanged();