[英]Implementing a Linked List Stack and Queue, and I don't know if the code I have set up is efficient enough
[英]i don't know how to complete this code to show the favorites list
早上好
我想將收藏夾列表添加到我的應用中,任何人都可以幫助我完成此代碼!
我沒有收到任何錯誤,但頁面為空。
任何幫助都很棒。
提前致謝!
收藏夾活動.java(此處的代碼我不知道如何完成)
public class FavoritesActivity extends AppCompatActivity {
RecyclerView recyclerView;
RecyclerView.LayoutManager layoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favorites);
recyclerView = findViewById(R.id.recycler_favorites);
recyclerView.setHasFixedSize(true);
LinearLayoutManager myLayoutManager = new LinearLayoutManager(this);
myLayoutManager.setReverseLayout(true);
myLayoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(myLayoutManager);
loadFavorites();
}
private void loadFavorites() {
FavoritesAdapter adapter = new FavoritesAdapter
(this, new Database(this).getAllFavorites("foodId"));
recyclerView.setAdapter(adapter);
}
}
這是收藏夾適配器.java
public class FavoritesAdapter extends RecyclerView.Adapter<FavoritesViewHolder> {
private Context context;
private List<Favorites> favoritesList;
public FavoritesAdapter(Context context, List<Favorites> favoritesList) {
this.context = context;
this.favoritesList = favoritesList;
}
@NonNull
@Override
public FavoritesViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(context).inflate(R.layout.favorites_item,parent,false);
return new FavoritesViewHolder(itemView);
}
@Override
public void onBindViewHolder(@NonNull FavoritesViewHolder viewHolder, final int position) {
viewHolder.food_name.setText(favoritesList.get(position).getName());
viewHolder.food_presenter.setText(String.format("%S", favoritesList.get(position).getName()));
Picasso.with(context).load(favoritesList.get(position).getImage())
.into(viewHolder.food_image);
final Favorites local = favoritesList.get(position);
viewHolder.setItemClickListener(new ItemClickListener() {
@Override
public void onClick(View view, int position, boolean isLongClick) {
//Start New Activity (Description Activity)
Intent foodDetails = new Intent(context, FavoritesActivity.class);
foodDetails.putExtra("FoodId",favoritesList.get(position).getFoodId()); //Send food ID to new activity
context.startActivity(foodDetails);
}
});
}
@Override
public int getItemCount() {
return favoritesList.size();
}
public void removeItem(int position){
favoritesList.remove(position);
notifyItemRemoved(position);
}
public void restoreItem(Favorites item, int position){
favoritesList.add(position,item);
notifyItemInserted(position);
}
public Favorites getItem(int position){
return favoritesList.get(position);
}
}
這是Database.java
public List<Favorites> getAllFavorites (String foodId)
{
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect={"FoodId", "FoodName", "FoodImage", "FoodDescription", "FoodComponents",
"FoodMenuId", "FoodUserName"};
String sqlTable = "Favorites";
qb.setTables(sqlTable);
Cursor cursor = qb.query(db,sqlSelect,"FoodId=?", new String[]{foodId}, null,null,null);
final List<Favorites> result = new ArrayList<>();
if (cursor.moveToFirst())
{
do {
result.add(new Favorites(
cursor.getString(cursor.getColumnIndex("FoodId")),
cursor.getString(cursor.getColumnIndex("FoodName")),
cursor.getString(cursor.getColumnIndex("FoodImage")),
cursor.getString(cursor.getColumnIndex("FoodDescription")),
cursor.getString(cursor.getColumnIndex("FoodComponents")),
cursor.getString(cursor.getColumnIndex("FoodMenuId")),
cursor.getString(cursor.getColumnIndex("FoodUserName"))
));
}while (cursor.moveToNext());
}
return result;
}
在loadFavorites()方法上調用adapter.notifyDataSetChanged() 。
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