我需要在许多地方获得用户对象,其中包含许多字段。登录后,我想保存/存储这些用户对象。我们如何实现这种场景?
我不能这样存储它:
SharedPreferences.Editor prefsEditor = myPrefs.edit();
prefsEditor.putString("BusinessUnit", strBusinessUnit);
我需要在许多地方获得用户对象,其中包含许多字段。登录后,我想保存/存储这些用户对象。我们如何实现这种场景?
我不能这样存储它:
SharedPreferences.Editor prefsEditor = myPrefs.edit();
prefsEditor.putString("BusinessUnit", strBusinessUnit);
当前回答
在SharedPreferences中存储Model的数组列表
Add this dependency implementation 'com.google.code.gson:gson:2.8.8' Then after you convert your Model Class into JSON using Gson. Gson gson = new Gson(); String json = gson.toJson(chModelArrayList); //here chModelArrayList is a ArrayList<Model> of Model Class Then after you can add this string to SharedPreferences SharedPreferences preferences; //Create Object of SharedPreferences SharedPreferences.Editor editor; //Create Object of SharedPreferences.Editor //initialize SharedPreferences preferences = activity.getPreferences(Context.MODE_PRIVATE); editor = preferences.edit(); //Add-In SharedPreferences editor.putString(key, json); editor.commit(); for your list from SharedPreferences String json = preferences.getString(key, defVal); Gson gson = new Gson(); //Pass Your Model ArrayList in TypeToken Type type = new TypeToken<ArrayList<ChModel>>() {}.getType(); //here you get your list ArrayList<ChModel> switchGroup1 = gson.fromJson(json, type);
其他回答
要添加到@MuhammadAamirALi的答案,您可以使用Gson保存和检索对象列表
保存用户定义对象的列表到SharedPreferences
public static final String KEY_CONNECTIONS = "KEY_CONNECTIONS";
SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
User entity = new User();
// ... set entity fields
List<Connection> connections = entity.getConnections();
// convert java object to JSON format,
// and returned as JSON formatted string
String connectionsJSONString = new Gson().toJson(connections);
editor.putString(KEY_CONNECTIONS, connectionsJSONString);
editor.commit();
从SharedPreferences获取用户定义对象的列表
String connectionsJSONString = getPreferences(MODE_PRIVATE).getString(KEY_CONNECTIONS, null);
Type type = new TypeToken < List < Connection >> () {}.getType();
List < Connection > connections = new Gson().fromJson(connectionsJSONString, type);
您可以使用以下代码存储类对象,并从共享首选项检索任何对象。
将以下依赖项添加到应用gradle中
dependencies {
implementation 'com.google.code.gson:gson:2.8.6'
//Other dependencies of our project
}
在共享pref文件中添加以下代码。
/**
* Saves object into the Preferences.
*
* @param `object` Object of model class (of type [T]) to save
* @param key Key with which Shared preferences to
**/
fun <T> put(`object`: T, key: String) {
//Convert object to JSON String.
val jsonString = GsonBuilder().create().toJson(`object`)
//Save that String in SharedPreferences
preferences.edit().putString(key, jsonString).apply()
}
/**
* Used to retrieve object from the Preferences.
*
* @param key Shared Preference key with which object was saved.
**/
inline fun <reified T> get(key: String): T? {
//We read JSON String which was saved.
val value = preferences.getString(key, null)
//JSON String was found which means object can be read.
//We convert this JSON String to model object. Parameter "c" (of
//type Class < T >" is used to cast.
return GsonBuilder().create().fromJson(value, T::class.java)
}
}
在SharedPreferences中存储Model的数组列表
Add this dependency implementation 'com.google.code.gson:gson:2.8.8' Then after you convert your Model Class into JSON using Gson. Gson gson = new Gson(); String json = gson.toJson(chModelArrayList); //here chModelArrayList is a ArrayList<Model> of Model Class Then after you can add this string to SharedPreferences SharedPreferences preferences; //Create Object of SharedPreferences SharedPreferences.Editor editor; //Create Object of SharedPreferences.Editor //initialize SharedPreferences preferences = activity.getPreferences(Context.MODE_PRIVATE); editor = preferences.edit(); //Add-In SharedPreferences editor.putString(key, json); editor.commit(); for your list from SharedPreferences String json = preferences.getString(key, defVal); Gson gson = new Gson(); //Pass Your Model ArrayList in TypeToken Type type = new TypeToken<ArrayList<ChModel>>() {}.getType(); //here you get your list ArrayList<ChModel> switchGroup1 = gson.fromJson(json, type);
如果你的对象很复杂,我建议序列化/XML/JSON,并将这些内容保存到SD卡。你可以在这里找到关于如何保存到外部存储的其他信息: http://developer.android.com/guide/topics/data/data-storage.html#filesExternal
有两个文件解决了共享首选项的所有问题
1)AppPersistence.java
public class AppPersistence {
public enum keys {
USER_NAME, USER_ID, USER_NUMBER, USER_EMAIL, USER_ADDRESS, CITY, USER_IMAGE,
DOB, MRG_Anniversary, COMPANY, USER_TYPE, support_phone
}
private static AppPersistence mAppPersistance;
private SharedPreferences sharedPreferences;
public static AppPersistence start(Context context) {
if (mAppPersistance == null) {
mAppPersistance = new AppPersistence(context);
}
return mAppPersistance;
}
private AppPersistence(Context context) {
sharedPreferences = context.getSharedPreferences(context.getString(R.string.prefrence_file_name),
Context.MODE_PRIVATE);
}
public Object get(Enum key) {
Map<String, ?> all = sharedPreferences.getAll();
return all.get(key.toString());
}
void save(Enum key, Object val) {
SharedPreferences.Editor editor = sharedPreferences.edit();
if (val instanceof Integer) {
editor.putInt(key.toString(), (Integer) val);
} else if (val instanceof String) {
editor.putString(key.toString(), String.valueOf(val));
} else if (val instanceof Float) {
editor.putFloat(key.toString(), (Float) val);
} else if (val instanceof Long) {
editor.putLong(key.toString(), (Long) val);
} else if (val instanceof Boolean) {
editor.putBoolean(key.toString(), (Boolean) val);
}
editor.apply();
}
void remove(Enum key) {
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.remove(key.toString());
editor.apply();
}
public void removeAll() {
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.clear();
editor.apply();
}
}
2)AppPreference.java
public static void setPreference(Context context, Enum Name, String Value) {
AppPersistence.start(context).save(Name, Value);
}
public static String getPreference(Context context, Enum Name) {
return (String) AppPersistence.start(context).get(Name);
}
public static void removePreference(Context context, Enum Name) {
AppPersistence.start(context).remove(Name);
}
}
现在你可以保存,删除或者获取,
保存
AppPreference.setPreference(context, AppPersistence.keys.USER_ID, userID);
删除
AppPreference.removePreference(context, AppPersistence.keys.USER_ID);
-get
AppPreference.getPreference(context, AppPersistence.keys.USER_ID);