我有一个对象的ArrayList。该对象包含类型＆＃39;位图＆＃39;和＆＃39; String＆＃39;然后只是两者的吸气剂和二传手。首先是Bitmap可序列化？
我如何将其序列化以将其存储在SharedPreferences中？我见过很多人问过类似的问题，但似乎没有人给出一个好的答案。如果可能的话，我会更喜欢一些代码示例。
如果位图不可序列化，那么我该如何存储这个ArrayList？
非常感谢。答案 0 :(得分：126)
是的，您可以将您的复合对象保存在共享首选项中。让我们说..
Student mStudentObject = new Student();
SharedPreferences appSharedPrefs = PreferenceManager
.getDefaultSharedPreferences(this.getApplicationContext());
Editor prefsEditor = appSharedPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(mStudentObject);
prefsEditor.putString("MyObject", json);
prefsEditor.commit();
..现在您可以将对象检索为：
SharedPreferences appSharedPrefs = PreferenceManager
.getDefaultSharedPreferences(this.getApplicationContext());
Gson gson = new Gson();
String json = appSharedPrefs.getString("MyObject", "");
Student mStudentObject = gson.fromJson(json, Student.class);
有关详情，请点击here.
如果您想要取回ArrayList任何类型的对象，例如Student，然后使用：
Type type = new TypeToken<List<Student>>(){}.getType();
List<Student> students = gson.fromJson(json, type);
答案 1 :(得分：110)
上面的答案有效，但不适用于列表：
对于保存对象列表，请执行以下操作：
List<Cars> cars= new ArrayList<Cars>();
cars.add(a);
cars.add(b);
cars.add(c);
cars.add(d);
gson = new Gson();
String jsonCars = gson.toJson(cars);
Log.d("TAG","jsonCars = " + jsonCars);
阅读json对象：
Type type = new TypeToken<List<Cars>>(){}.getType();
List<Cars> carsList = gson.fromJson(jsonCars, type);
答案 2 :(得分：20)
对我而言，它的工作原理如下：
将值放在SharedPreferances中：
String key = "Key";
ArrayList<ModelClass> ModelArrayList=new ArrayList();
SharedPreferences shref;
SharedPreferences.Editor editor;
shref = context.getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
Gson gson = new Gson();
String json = gson.toJson(ModelArrayList);
editor = shref.edit();
editor.remove(key).commit();
editor.putString(key, json);
editor.commit();
从SharedPreferances获取值：
Gson gson = new Gson();
String response=shref.getString(key , "");
ArrayList<ModelClass> lstArrayList = gson.fromJson(response,
new TypeToken<List<ModelClass>>(){}.getType());
答案 3 :(得分：12)
保存：
public static void saveSharedPreferencesLogList(Context context, List<PhoneCallLog> callLog) {
SharedPreferences mPrefs = context.getSharedPreferences(Constant.CALL_HISTORY_RC, context.MODE_PRIVATE);
SharedPreferences.Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(callLog);
prefsEditor.putString("myJson", json);
prefsEditor.commit();
}
负载：
public static List<PhoneCallLog> loadSharedPreferencesLogList(Context context) {
List<PhoneCallLog> callLog = new ArrayList<PhoneCallLog>();
SharedPreferences mPrefs = context.getSharedPreferences(Constant.CALL_HISTORY_RC, context.MODE_PRIVATE);
Gson gson = new Gson();
String json = mPrefs.getString("myJson", "");
if (json.isEmpty()) {
callLog = new ArrayList<PhoneCallLog>();
} else {
Type type = new TypeToken<List<PhoneCallLog>>() {
}.getType();
callLog = gson.fromJson(json, type);
}
return callLog;
}
PhoneCallLog是我的自定义对象的名称。 （包含String，long和boolean值）
答案 4 :(得分：2)
解决方案
别担心，您可以按照我的代码进行操作。我正在使用自己的 sharedPreference 自定义类在 sharedPreference 中保存任何类型的 List。
public class AuthPreference {
private static final String MY_PREFERENCES = "MY_PREFERENCES";
private static final int MODE = Context.MODE_PRIVATE;
private static AuthPreference pref;
private final SharedPreferences sharedPreference;
private final SharedPreferences.Editor editor;
@SuppressLint("CommitPrefEdits")
public AuthPreference(Context context) {
sharedPreference = context.getSharedPreferences(MY_PREFERENCES, MODE);
editor = sharedPreference.edit();
}
public void clear() {
editor.clear().commit();
}
//Here save your api responce like YourModel arraylist
public void saveDataResponce(ArrayList<YourModel> model_, String key) {
SharedPreferences.Editor editor = sharedPreference.edit();
Gson gson = new Gson();
String json = gson.toJson(model_);
editor.putString(key, json);
editor.apply();
}
//Here we get our api responce like YourModel arraylist.Using key value when you want to define.
public ArrayList<YourModel> getDataResponce(String key) {
Gson gson = new Gson();
String json = sharedPreference.getString(key, null);
Type type_ = new TypeToken<ArrayList<YourModel>>() {
}.getType();
return gson.fromJson(json, type_);
}
}
答案 5 :(得分：1)
使用Gson的kotlin实现，扩展了@SpyZips的答案，
序列化为JSON
val jsonCars: String = Gson().toJson(cars);
反序列化回到objs列表
val type = object: TypeToken<List<Car>>(){}.type
val carsList: List<Car> = Gson().fromJson(jsonCars, type)
答案 6 :(得分：0)
在共享首选项中编写代码：
public class MySharedPrefernce {
private Context context;
private String PREF_NAME = "UserPreference";
private int PRIVATE_MODE = 0;
private SharedPreferences preferences;
private SharedPreferences.Editor editor;
private DataKey = "CART_RESTAURANTS";
//constructor
public MySharedPrefernce(Context context) {
this.context = context;
this.preferences = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = preferences.edit();
}
//add data
public void saveRestaurantToSharedPrefs(List<CartRestaurantModel> cartRestaurantModel) {
Gson gson = new Gson();
String jsonCart = gson.toJson(cartRestaurantModel);
editor.putString(DataKey, jsonCart);
editor.commit();
}
//get data
public ArrayList<CartRestaurantModel> getRestaurantToSharedPrefs() {
List<CartRestaurantModel> cartData;
if (preferences.contains(DataKey)) {
String jsonCart = preferences.getString(DataKey, null);
Gson gson = new Gson();
CartRestaurantModel[] cartItems = gson.fromJson(jsonCart,
CartRestaurantModel[].class);
cartData = Arrays.asList(cartItems);
cartData = new ArrayList<CartRestaurantModel>(cartData);
} else {
try {
return new ArrayList<CartRestaurantModel>();
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
return (ArrayList<CartRestaurantModel>) cartData;
}
//clear data
public void clearRestaurantSharedPrefsData() {
editor.clear();
editor.commit();
}
}
在您的活动/片段中编写代码以存储和检索：
public List<CartRestaurantModel> cartRestaurantModel = new ArrayList<CartRestaurantModel>(); // to maintain restaurant for cart menus
待店：
new MySharedPrefernce(this).saveRestaurantToSharedPrefs(cartRestaurantModel);
要检索：
cartRestaurantModel = new MySharedPrefernce(this).getRestaurantToSharedPrefs();
答案 7 :(得分：0)
##对于单次调用和检索列表，请使用## ` 列表模型=新的ArrayList <>（）;
Gson gson = new Gson();
String value= gson.toJson(models);
PreferenceManager.getDefaultSharedPreferences(context).edit().putString(value, "StringValueToRetrieve").apply();
String value=PreferenceManager.getDefaultSharedPreferences(context).getString("StringValueToRetrieve", "noValue");
if(!value.contains("noValue")){
Gson gson = new Gson();
List<Model> models= gson.fromJson(value,
new TypeToken<List<Model>>(){}.getType());
}
`
答案 8 :(得分：0)
假设您有一个名为“药物治疗”的课程。您可以使用以下功能：
public static void saveMedicineToList(Medication medication){
ArrayList<Medication> medicationArrayList = getListOfMedication();
if(medicationArrayList == null) medicationArrayList = new ArrayList<>();
medicationArrayList.add(medication);
saveListOfMedicine(medicationArrayList);
}
public static void saveListOfMedicine(ArrayList<Medication> medicationArrayList){
SharedPreferences shref;
SharedPreferences.Editor editor;
shref = PreferenceManager.getDefaultSharedPreferences(SakshamApp.getInstance());
Gson gson = new Gson();
String json = gson.toJson(medicationArrayList);
editor = shref.edit();
editor.remove(KEY_MIDICINES_LIST).commit();
editor.putString(KEY_MIDICINES_LIST, json);
editor.commit();
}
public static ArrayList<Medication> getListOfMedication(){
SharedPreferences shref = PreferenceManager.getDefaultSharedPreferences(SakshamApp.getInstance());
Gson gson = new Gson();
String response=shref.getString(KEY_MIDICINES_LIST , "");
ArrayList<Medication> medicationArrayList = gson.fromJson(response,
new TypeToken<List<Medication>>(){}.getType());
return medicationArrayList;
}
答案 9 :(得分：0)
上面的“ Mete”示例就像一个魅力一样。
这是一个科特林示例
private var prefs: SharedPreferences = context?.getSharedPreferences("sharedPrefs", MODE_PRIVATE)
?: error("err")
private val gson = Gson()
保存
fun saveObjectToArrayList(yourObject: YourObject) {
val bookmarks = fetchArrayList()
bookmarks.add(0, yourObject)
val prefsEditor = prefs.edit()
val json = gson.toJson(bookmarks)
prefsEditor.putString("your_key", json)
prefsEditor.apply()
}
阅读
fun fetchArrayList(): ArrayList<YourObject> {
val yourArrayList: ArrayList<YourObject>
val json = prefs.getString("your_key", "")
yourArrayList = when {
json.isNullOrEmpty() -> ArrayList()
else -> gson.fromJson(json, object : TypeToken<List<Feed>>() {}.type)
}
return yourArrayList
}