All geek questions in one place

Adding a favorite list button

I have a listview that has a favorite button for each list item that, when clicked, should add a list item to another action called my fav9rites. I use the Baseadapter for listview and Sharedpreference to add favorites. When I click the Favorites button, the list view item is added to my activity, but I am having the following problems:

1), when you click on the "Favorites" button, a darkness should appear indicating that the list item has been added to your favorites. This happens, but when I close the activity and come back again, the button comes back, not dark

2) with a long press on the list item in my activity, the selected list item should be removed from the favorites, but this does not happen.

Hope everyone understands my question.

My code

my base adapter

 public View getView(final int position, View view, ViewGroup parent) { final ViewHolder holder; if(view == null){ holder = new ViewHolder(); view = inflater.inflate(R.layout.beg_list_item,null); holder.listHeading = (TextView) view.findViewById(R.id.beg_list_itemTextView); // holder.listHash = (TextView) view.findViewById(R.id.listview_hashtags); holder.alphabetList = (ImageView) view.findViewById(R.id.beg_list_itemImageView); holder.favoriteImg = (ImageView) view.findViewById(R.id.favbtn); view.setTag(holder); }else{ holder = (ViewHolder) view.getTag(); } CodeList code = (CodeList) getItem(position); holder.listHeading.setText(codeList.get(position).getListHeading()); imageLoader.DisplayImage(codeList.get(position).getAlphabetimg(), holder.alphabetList); // holder.listHash.setText(codeList.get(position).getListHashTags()); if (checkFavoriteItem(code)) { holder.favoriteImg.setImageResource(R.drawable.favorite); holder.favoriteImg.setTag("yes"); } else { holder.favoriteImg.setImageResource(R.drawable.unfavorite); holder.favoriteImg.setTag("no"); } view.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0){ Intent intent = new Intent(context, SingleItemView.class); //intent.putExtra("listheading", // (codeList.get(position).getListHeading())); //intent.putExtra("alphabetimg", // (codeList.get(position).getAlphabetimg())); intent.putExtra("demovideo", (codeList.get(position).getDailogdemovideo())); intent.putExtra("download", (codeList.get(position).getDownloadCode())); // Start SingleItemView Class context.startActivity(intent); } }); final ImageView favoritesbutton = (ImageView) view.findViewById(R.id.favbtn); favoritesbutton.setOnClickListener(new OnClickListener(){ @Override public void onClick(View v){ String tag = favoritesbutton.getTag().toString(); if(tag.equalsIgnoreCase("no")){ shrdPrefence.addFavorite(context, codeList.get(position)); Toast.makeText(context, R.string.fav_added, Toast.LENGTH_SHORT).show(); favoritesbutton.setTag("yes"); favoritesbutton.setImageResource(R.drawable.favorite); }else{ shrdPrefence.removeFavorite(context, codeList.get(position)); favoritesbutton.setTag("no"); favoritesbutton.setImageResource(R.drawable.unfavorite); Toast.makeText(context, R.string.fav_removed, Toast.LENGTH_SHORT).show(); } } }); return view; } //Checks whether a particular product exists in SharedPreferences*/ public boolean checkFavoriteItem(CodeList checkCode) { boolean check = false; List<CodeList> favorites = shrdPrefence.getFavorites(context); if (favorites != null) { for (CodeList code : favorites) { if (code.equals(checkCode)) { check = true; break; } } } return check; } public void add(CodeList code) { codeList.add(code); notifyDataSetChanged(); } public void remove(CodeList code) { codeList.remove(code); notifyDataSetChanged(); }

sharedpreference.java

 public class SharedPreference { public static final String PREFS_NAME = "MY_APP"; public static final String FAVORITES = "code_Favorite"; public SharedPreference(){ super(); } public void saveFavorites(Context context, List<CodeList> 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.commit(); } public void addFavorite(Context context, CodeList code){ List<CodeList> favorites = getFavorites(context); if(favorites == null) favorites = new ArrayList<CodeList>(); favorites.add(code); saveFavorites(context,favorites); } public void removeFavorite(Context context, CodeList code) { ArrayList<CodeList> favorites = getFavorites(context); if (favorites != null) { favorites.remove(code); saveFavorites(context, favorites); } } public ArrayList<CodeList> getFavorites(Context context) { SharedPreferences settings; List<CodeList> favorites; settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE); if (settings.contains(FAVORITES)) { String jsonFavorites = settings.getString(FAVORITES, null); Gson gson = new Gson(); CodeList[] favoriteItems = gson.fromJson(jsonFavorites, CodeList[].class); favorites = Arrays.asList(favoriteItems); favorites = new ArrayList<CodeList>(favorites); } else return null; return (ArrayList<CodeList>) favorites; } }

my favorite .. java

  public class MyFavActivity extends Activity { SharedPreference shrdPrfence; List<CodeList> favorites; FinalAdapter fnlAdpter; Context context = this.context; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fav_layout); shrdPrfence = new SharedPreference(); favorites = shrdPrfence.getFavorites(MyFavActivity.this); if(favorites == null){ Dialog dialog = new Dialog(MyFavActivity.this); dialog.setTitle(R.string.nofav_title); dialog.show(); }else{ if(favorites.size() == 0){ Dialog dialog = new Dialog(MyFavActivity.this); dialog.setTitle(R.string.nofav_title); dialog.show(); } ListView favList = (ListView) findViewById(R.id.fav_layoutListView); if(favorites != null){ fnlAdpter = new FinalAdapter(MyFavActivity.this, favorites); favList.setAdapter(fnlAdpter); favList.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View arg1, int position, long arg3) { } }); favList.setOnItemLongClickListener(new OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { ImageView button = (ImageView) view .findViewById(R.id.favbtn); String tag = button.getTag().toString(); if (tag.equalsIgnoreCase("no")) { shrdPrfence.addFavorite(MyFavActivity.this, favorites.get(position)); Toast.makeText( MyFavActivity.this, R.string.fav_added, Toast.LENGTH_SHORT).show(); button.setTag("yes"); button.setImageResource(R.drawable.favorite); } else { shrdPrfence.removeFavorite(MyFavActivity.this, favorites.get(position)); button.setTag("no"); button.setImageResource(R.drawable.unfavorite); fnlAdpter.remove(favorites.get(position)); Toast.makeText( MyFavActivity.this, R.string.fav_removed, Toast.LENGTH_SHORT).show(); } return true; } }); } } } }
+5
source share
1 answer

Actually your saveFavorites () method works fine, because you just call gson.toJson () (convert everything in json format)

You want to retrieve saved data using SharedPreferences, and you used this line to retrieve your data.

  gson.fromJson(jsonFavorites, CodeList[].class);

you will never get your saved data in this line, because you save the list and want to get an array (!)

If you saved the list, you must retrieve your data using the list token. And you need this line

  gson.fromJson(jsonFavorites,new TypeToken<ArrayList<CodeList>>() {}.getType());

I think this will solve your question. Good luck.

+2
source

Source: https://habr.com/ru/post/1239238/

More articles:


All Articles