我正在尝试将共享首选项中的recyclerview条目保存为收藏夹。我想在每个recyclerview条目中实现“收藏夹”按钮。我已经完成了设计部分。我的代码还可以完美地用于在共享首选项中添加条目，并通过recyclerview在“ FavoritesActivity”中显示该条目。
我的问题：
我尝试了很多，并测试了各种代码。我也搜索stackoverflow和其他网站，但很伤心：（
MySharedPreference类
public class MySharedPreference {
public static final String PREFS_NAME = "MY_APP";
public static final String FAVORITES = "Profile_Favorite";
public MySharedPreference() {
super();
}
// This four methods are used for maintaining favorites.
public void saveFavorites(Context context, List<ProfileModel> favorites) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
editor = settings.edit();
Gson gson = new Gson();
String jsonFavorites = gson.toJson(favorites);
editor.putString(FAVORITES, jsonFavorites);
editor.apply();
}
public void addFavorite(Context context, ProfileModel ProfileModel) {
List<ProfileModel> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<ProfileModel>();
favorites.add(ProfileModel);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, ProfileModel ProfileModel) {
ArrayList<ProfileModel> favorites = getFavorites(context);
if (favorites != null) {
favorites.remove(ProfileModel);
saveFavorites(context, favorites);
}
}
public ArrayList<ProfileModel> getFavorites(Context context) {
SharedPreferences settings;
List<ProfileModel> favorites;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
ProfileModel[] favoriteItems = gson.fromJson(jsonFavorites,
ProfileModel[].class);
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<ProfileModel>(favorites);
} else
return null;
return (ArrayList<ProfileModel>) favorites;
}
}
我的适配器
public class ProfileAdapter extends RecyclerView.Adapter<ProfilePostAdapter.PostViewHolder> {
MySharedPreference mySharedPreference;
private Context context;
List<ProfileModel> items;
public ProfileAdapter(Context context, List<ProfileModel> items) {
this.context = context;
this.items = items;
mySharedPreference = new MySharedPreference();
}
@Override
public PostViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.single_profile_item, parent, false);
return new PostViewHolder(view);
}
@Override
public void onBindViewHolder(final PostViewHolder holder, final int position) {
final ProfileModel item = items.get(position);
holder.profileID.setText(item.getId());
holder.profileTitle.setText(item.getTitle());
holder.profileDescription.setText(document.text());
if (checkFavoriteItem(item)) {
holder.mFavIcon.setImageResource(R.drawable.ic_fav_filled);
holder.mFavIcon.setTag("red");
} else {
holder.mFavIcon.setImageResource(R.drawable.ic_fav_blank);
holder.mFavIcon.setTag("grey");
}
Document document = Jsoup.parse(item.getContent());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context, ProfileDetailActivity.class);
intent.putExtra("title", item.getTitle());
intent.putExtra("description", item.getDescription());
intent.putExtra("Id", item.getId());
context.startActivity(intent);
}
});
holder.mFavoriteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ImageView button = v.findViewById(R.id.img_fav_profile);
String tag = button.getTag().toString();
if (tag.equals("grey")) {
mySharedPreference.addFavorite(context, items.get(position));
Toast.makeText(context,
v.getResources().getString(R.string.add_favr),
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.ic_fav_filled);
}
else if (tag.equals("red")) {
mySharedPreference.removeFavorite(context, items.get(position));
Toast.makeText(context,
v.getResources().getString(R.string.remove_favr),
Toast.LENGTH_SHORT).show();
button.setTag("grey");
button.setImageResource(R.drawable.ic_fav_blank);
}
}
});
}
@Override
public int getItemCount() {
return items.size();
}
class PostViewHolder extends RecyclerView.ViewHolder {
TextView profileTitle;
TextView profileDescription;
TextView profileID;
PostViewHolder(View itemView) {
super(itemView);
profileTitle = itemView.findViewById(R.id.profileTitle);
profileDescription = itemView.findViewById(R.id.profileDescription);
mFavoriteProfile = itemView.findViewById(R.id.img_fav_profile);
profileID = itemView.findViewById(R.id.profileID);
}
}
public boolean checkFavoriteItem(ProfileModel checkProfile) {
boolean check = false;
List<ProfileModel> favorites = mySharedPreference.getFavorites(context);
if (favorites != null) {
for (ProfileModel profile : favorites) {
if (profile.equals(checkProfile)) {
check = true;
break;
}
}
}
return check;
}
}
FavoriteActivity
public class FavoriteActivity extends AppCompatActivity {
Toolbar mToolbar;
MySharedPreference mySharedPreference;
@Override
protected void onCreate(Bundle savedInstanceState) {
final ListView favoriteList;
final MySharedPreference myshrdprefernces;
final List<ProfileModel> favorites;
final ProfileFavAdapter fnladpter;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile_favorite);
mToolbar = (Toolbar) findViewById(R.id.profile_fav_page_toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setTitle("Favorites");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
myshrdprefernces = new MySharedPreference();
favorites = myshrdprefernces.getFavorites(FavoriteActivity.this);
if (favorites == null) {
showAlert(getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
} else {
if (favorites.size() == 0) {
showAlert(
getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
}
favoriteList = (ListView) findViewById(R.id.list_product);
if (favorites != null) {
fnladpter = new ProfileFavAdapter(FavoriteActivity.this, favorites);
favoriteList.setAdapter(fnladpter);
favoriteList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View arg1,
int position, long arg3) {
}
});
favoriteList
.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(
AdapterView<?> parent, View view,
int position, long id) {
ImageView button = (ImageView) view
.findViewById(R.id.img_fav_profile);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("no")) {
myshrdprefernces.addFavorite(FavoriteActivity.this,
favorites.get(position));
Toast.makeText(
FavoriteActivity.this,
getString(
R.string.add_favr),
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.ic_fav_filled);
} else {
myshrdprefernces.removeFavorite(FavoriteActivity.this,
favorites.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_fav_blank);
fnladpter.remove(favorites.get(position));
Toast.makeText(
FavoriteActivity.this,
getString(
R.string.remove_favr),
Toast.LENGTH_SHORT).show();
}
return true;
}
});
}
}
}
请指导我怎么了？我真的尝试了很多。再一次，一切正常，只有两个问题。
当我单击FavoriteActivity的recyclerview时，将从recyclerview中删除该项目，但是当我关闭活动并再次打开它时，它就会出现。意思是，实际上它并没有消除。
我的适配器未将条目显示为收藏夹（均值，实心图标）。
谢谢。