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
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);
其他回答
另一种不使用Json格式保存和恢复android sharedpreferences对象的方法
private static ExampleObject getObject(Context c,String db_name){
SharedPreferences sharedPreferences = c.getSharedPreferences(db_name, Context.MODE_PRIVATE);
ExampleObject o = new ExampleObject();
Field[] fields = o.getClass().getFields();
try {
for (Field field : fields) {
Class<?> type = field.getType();
try {
final String name = field.getName();
if (type == Character.TYPE || type.equals(String.class)) {
field.set(o,sharedPreferences.getString(name, ""));
} else if (type.equals(int.class) || type.equals(Short.class))
field.setInt(o,sharedPreferences.getInt(name, 0));
else if (type.equals(double.class))
field.setDouble(o,sharedPreferences.getFloat(name, 0));
else if (type.equals(float.class))
field.setFloat(o,sharedPreferences.getFloat(name, 0));
else if (type.equals(long.class))
field.setLong(o,sharedPreferences.getLong(name, 0));
else if (type.equals(Boolean.class))
field.setBoolean(o,sharedPreferences.getBoolean(name, false));
else if (type.equals(UUID.class))
field.set(
o,
UUID.fromString(
sharedPreferences.getString(
name,
UUID.nameUUIDFromBytes("".getBytes()).toString()
)
)
);
} catch (IllegalAccessException e) {
Log.e(StaticConfig.app_name, "IllegalAccessException", e);
} catch (IllegalArgumentException e) {
Log.e(StaticConfig.app_name, "IllegalArgumentException", e);
}
}
} catch (Exception e) {
System.out.println("Exception: " + e);
}
return o;
}
private static void setObject(Context context, Object o, String db_name) {
Field[] fields = o.getClass().getFields();
SharedPreferences sp = context.getSharedPreferences(db_name, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
for (Field field : fields) {
Class<?> type = field.getType();
try {
final String name = field.getName();
if (type == Character.TYPE || type.equals(String.class)) {
Object value = field.get(o);
if (value != null)
editor.putString(name, value.toString());
} else if (type.equals(int.class) || type.equals(Short.class))
editor.putInt(name, field.getInt(o));
else if (type.equals(double.class))
editor.putFloat(name, (float) field.getDouble(o));
else if (type.equals(float.class))
editor.putFloat(name, field.getFloat(o));
else if (type.equals(long.class))
editor.putLong(name, field.getLong(o));
else if (type.equals(Boolean.class))
editor.putBoolean(name, field.getBoolean(o));
else if (type.equals(UUID.class))
editor.putString(name, field.get(o).toString());
} catch (IllegalAccessException e) {
Log.e(StaticConfig.app_name, "IllegalAccessException", e);
} catch (IllegalArgumentException e) {
Log.e(StaticConfig.app_name, "IllegalArgumentException", e);
}
}
editor.apply();
}
将数据存储在SharedPreference中
SharedPreferences mprefs = getSharedPreferences(AppConstant.PREFS_NAME, MODE_PRIVATE)
mprefs.edit().putString(AppConstant.USER_ID, resUserID).apply();
您可以使用gson.jar将类对象存储到SharedPreferences中。 你可以从google-gson下载这个罐子
或者在Gradle文件中添加GSON依赖项:
implementation 'com.google.code.gson:gson:2.8.8'
你可以在这里找到最新的版本
创建共享首选项:
SharedPreferences mPrefs = getPreferences(MODE_PRIVATE);
保存:
MyObject myObject = new MyObject;
//set variables of 'myObject', etc.
Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myObject);
prefsEditor.putString("MyObject", json);
prefsEditor.commit();
检索:
Gson gson = new Gson();
String json = mPrefs.getString("MyObject", "");
MyObject obj = gson.fromJson(json, MyObject.class);
关于这个问题有很多很好的答案,穆罕穆德·阿米尔·阿里和穆哈默德·埃尔-班纳在Kotlin使用通用方法实现了答案。
为了节省
fun storeObjectInSharedPref(dataObject: Any, prefName: String): Boolean{
val dataObjectInJson = Gson().toJson(dataObject)
prefsEditor.putString(prefName, dataObjectInJson)
return prefsEditor.commit()
}
检索
fun <T> retrieveStoredObject(prefName: String, baseClass: Class<T>): T?{
val dataObject: String? = preferences.getString(prefName, "")
return Gson().fromJson(dataObject, baseClass)
}
要了解Kotlin中的泛型,请访问这里
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);