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
将数据存储在SharedPreference中
SharedPreferences mprefs = getSharedPreferences(AppConstant.PREFS_NAME, MODE_PRIVATE)
mprefs.edit().putString(AppConstant.USER_ID, resUserID).apply();
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);
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();
}
我在使用已接受的答案访问跨活动的共享首选项数据时遇到了麻烦。在这些步骤中,您将为getSharedPreferences提供一个名称以访问它。
在构建中添加以下依赖项。Gradle脚本下的gradel (Module: app)文件:
implementation 'com.google.code.gson:gson:2.8.5'
保存:
MyObject myObject = new MyObject;
//set variables of 'myObject', etc.
SharedPreferences mPrefs = getSharedPreferences("Name", Context.MODE_PRIVATE);
Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myObject);
prefsEditor.putString("Key", json);
prefsEditor.commit();
在不同的活动中检索:
SharedPreferences mPrefs = getSharedPreferences("Name", Context.MODE_PRIVATE);
Gson gson = new Gson();
String json = mPrefs.getString("Key", "");
MyObject obj = gson.fromJson(json, MyObject.class);
我的utils类保存列表到SharedPreferences
public class SharedPrefApi {
private SharedPreferences sharedPreferences;
private Gson gson;
public SharedPrefApi(Context context, Gson gson) {
this.sharedPreferences = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
this.gson = gson;
}
...
public <T> void putObject(String key, T value) {
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, gson.toJson(value));
editor.apply();
}
public <T> T getObject(String key, Class<T> clazz) {
return gson.fromJson(getString(key, null), clazz);
}
}
使用
// for save
sharedPrefApi.putList(SharedPrefApi.Key.USER_LIST, userList);
// for retrieve
List<User> userList = sharedPrefApi.getList(SharedPrefApi.Key.USER_LIST, User.class);
. 我的utils的完整代码//检查使用实例的活动代码
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