无法从保存在共享preferences对象的字符串中删除对象 [英] Unable to remove object from string of objects saved in sharedPreferences
问题描述
我已经寻找解决这个问题,但我没有得到一个答案,我不知道这是否已经然而面前回答。我得到了code在线保存对象在使用GSON库共享preferences JSON字符串并适应它使用了。
在code工作,除了罚款,当我需要从共享preferences删除项目。该项目不会删除。请帮我看看到code。 C $ CS中的$粘贴如下图所示。
对象类:
公共类fPerson {字符串名称,编号,类型,猫;公共fPerson(字符串纳米,字符串ID,典型的字符串,字符串CT)
{
this.name =纳米;
this.id = ID;
this.type =(典型值);
this.cat =克拉;
}公共无效setname可以(字符串n)
{
this.name = N;
}公共无效SETID(字符串一)
{
this.id = I;
}公共无效的setType(字符串TY)
{
this.type = TY;
}公共无效setCat(字符串克拉)
{
this.cat =克拉;
}公共字符串的getName()
{
返回this.name;
}公共字符串的getId()
{
返回this.id;
}公共字符串的getType()
{
返回this.type;
}公共字符串getCat()
{
返回this.cat;
}公共字符串的toString()
{
返回新的String(的getName()++的getId()++的getType());
}}
与共享preferences类
公共类$ P $ {pferences公共静态最后弦乐preFS_NAME =APP;
公共静态最后弦乐收藏夹=收藏夹;公共preferences(){
超();
}
公共无效saveFavorites(上下文的背景下,列表与LT; fPerson>的最爱){
共享preferences设置;
编辑器编辑; 设置= context.getShared preferences(preFS_NAME,Context.MODE_PRIVATE);
编辑= settings.edit(); GSON GSON =新GSON();
字符串jsonFavorites = gson.toJson(收藏夹); editor.putString(收藏,jsonFavorites); editor.commit();
}公共无效加入收藏(上下文的背景下,fPerson人){
清单< fPerson>收藏= getFavorites(背景);
如果(收藏== NULL)
最爱=新的ArrayList< fPerson>();
favorites.add(人);
saveFavorites(背景下,收藏);
}公共无效removeFavorite(上下文的背景下,fPerson人){
ArrayList的< fPerson>收藏= getFavorites(背景);
如果(收藏夹!= NULL){
迭代器< fPerson> ITER = favorites.listIterator();
而(iter.hasNext())
{
fPerson TEMP =(fPerson)iter.next();
如果(temp.getId()。等于(person.getId()))
{
favorites.remove(人);
打破;
}
}
saveFavorites(背景下,收藏);
}
}公众的ArrayList< fPerson> getFavorites(上下文的背景下){
共享preferences设置;
清单< fPerson>收藏夹; 设置= context.getShared preferences(preFS_NAME,Context.MODE_PRIVATE); 如果(settings.contains(收藏夹)){
字符串jsonFavorites = settings.getString(收藏,NULL);
GSON GSON =新GSON();
fPerson [] = favoriteItems gson.fromJson(jsonFavorites,fPerson []类); 收藏= Arrays.asList(favoriteItems);
最爱=新的ArrayList< fPerson>(收藏夹); }其他
返回null; 回报(ArrayList的< fPerson>)收藏夹;
}}
有关谁就可能具有相同挑战的目的,终于得到了一个解决问题的办法。除了使用removeFavorite()方法中,我所做的就是让fPerson列表,删除我要的项目,并在preferences重新保存列表下的同名像这样...
fp.remove(rposition);
我的pref.saveFavorites(getApplicationContext(),FP);
I have searched for solution to this problem but I have not got an answer, I don't know if it has been answered before however. I got a code online to save objects as JSON string in SharedPreferences using the Gson library and adapted it for use.
The code works fine except for when I need to remove an item from SharedPreferences. The item does not remove. Please help me look into the code. The codes are pasted as shown below.
The object class:
public class fPerson {
String name, id, type, cat;
public fPerson(String nm, String ID, String typ, String ct)
{
this.name = nm;
this.id = ID;
this.type = typ;
this.cat = ct;
}
public void setName(String n)
{
this.name = n;
}
public void setId(String i)
{
this.id = i;
}
public void settype(String ty)
{
this.type = ty;
}
public void setCat(String ct)
{
this.cat = ct;
}
public String getName()
{
return this.name;
}
public String getId()
{
return this.id;
}
public String getType()
{
return this.type;
}
public String getCat()
{
return this.cat;
}
public String toString()
{
return new String(getName() + " " + getId()+ " " + getType());
}
}
The class with the SharedPreferences
public class Preferences {
public static final String PREFS_NAME = "APP";
public static final String FAVORITES = "Favorite";
public Preferences() {
super();
}
public void saveFavorites(Context context, List<fPerson> 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, fPerson person) {
List<fPerson> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<fPerson>();
favorites.add(person);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, fPerson person) {
ArrayList<fPerson> favorites = getFavorites(context);
if (favorites != null) {
Iterator<fPerson> iter = favorites.listIterator();
while(iter.hasNext())
{
fPerson temp = (fPerson)iter.next();
if(temp.getId().equals(person.getId()))
{
favorites.remove(person);
break;
}
}
saveFavorites(context, favorites);
}
}
public ArrayList<fPerson> getFavorites(Context context) {
SharedPreferences settings;
List<fPerson> favorites;
settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
fPerson[] favoriteItems = gson.fromJson(jsonFavorites, fPerson[].class);
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<fPerson>(favorites);
} else
return null;
return (ArrayList<fPerson>) favorites;
}
}
For the purpose of whoever might be having the same challenge, finally got a solution to the problem. Instead of using the removeFavorite() method, what I did was to get the list of fPerson, remove the item I want to and save the list afresh in preferences under the same name like so... fp.remove(rposition); myPref.saveFavorites(getApplicationContext(), fp);
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