我有一个listview，每个列表项都有一个收藏夹按钮，点击后应该将列表项添加到另一个名为my fav9rites的活动中。我使用Baseadapter listview和Sharedpreference添加收藏夹。
当我单击收藏夹按钮时，列表视图项目将添加到我的收藏夹活动中，但我遇到以下问题：
1）点击时的收藏夹按钮应变暗，表示列表项已添加到收藏夹。发生这种情况但是当我关闭活动并再次返回时，按钮会返回而不是变暗（
）2）在我的收藏夹活动中长按列表项目时，应从收藏夹中删除列表项目，但这不会发生。
希望每个人都理解我的问题
我的代码
我的基础适配器
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;
}
}
我最喜欢的..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;
}
});
}
}
}
}
答案 0 :(得分：2)
实际上你的 saveFavorites（）方法运行正常，不过你只需要调用 gson.toJson（）（以json格式转换所有内容）
您希望使用SharedPreferences获取已保存的数据，并且您已使用此行检索数据
gson.fromJson(jsonFavorites, CodeList[].class);
您永远不会使用此行获取已保存的数据，因为您保存了列表，并且想要检索数组 （！） < / p>
如果您保存了列表，则必须使用列表标记来检索数据。你需要这一行
gson.fromJson(jsonFavorites,new TypeToken<ArrayList<CodeList>>() {}.getType());
我认为这将解决您的问题。祝你好运。