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
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);
其他回答
// SharedPrefHelper is a class contains the get and save sharedPrefernce data
public class SharedPrefHelper {
// save data in sharedPrefences
public static void setSharedOBJECT(Context context, String key,
Object value) {
SharedPreferences sharedPreferences = context.getSharedPreferences(
context.getPackageName(), Context.MODE_PRIVATE);
SharedPreferences.Editor prefsEditor = sharedPreferences.edit();
Gson gson = new Gson();
String json = gson.toJson(value);
prefsEditor.putString(key, json);
prefsEditor.apply();
}
// get data from sharedPrefences
public static Object getSharedOBJECT(Context context, String key) {
SharedPreferences sharedPreferences = context.getSharedPreferences(
context.getPackageName(), Context.MODE_PRIVATE);
Gson gson = new Gson();
String json = sharedPreferences.getString(key, "");
Object obj = gson.fromJson(json, Object.class);
User objData = new Gson().fromJson(obj.toString(), User.class);
return objData;
}
}
// save data in your activity
User user = new User("Hussein","h@h.com","3107310890983");
SharedPrefHelper.setSharedOBJECT(this,"your_key",user);
User data = (User) SharedPrefHelper.getSharedOBJECT(this,"your_key");
Toast.makeText(this,data.getName()+"\n"+data.getEmail()+"\n"+data.getPhone(),Toast.LENGTH_LONG).show();
// User is the class you want to save its objects
public class User {
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
private String name,email,phone;
public User(String name,String email,String phone){
this.name=name;
this.email=email;
this.phone=phone;
}
}
// put this in gradle
compile 'com.google.code.gson:gson:2.7'
希望这对你有所帮助:)
使用delegate Kotlin,我们可以轻松地从共享首选项中放置和获取数据。
inline fun <reified T> Context.sharedPrefs(key: String) = object : ReadWriteProperty<Any?, T> {
val sharedPrefs by lazy { this@sharedPrefs.getSharedPreferences("APP_DATA", Context.MODE_PRIVATE) }
val gson by lazy { Gson() }
var newData: T = (T::class.java).newInstance()
override fun getValue(thisRef: Any?, property: KProperty<*>): T {
return getPrefs()
}
override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
this.newData = value
putPrefs(newData)
}
fun putPrefs(value: T?) {
sharedPrefs.edit {
when (value) {
is Int -> putInt(key, value)
is Boolean -> putBoolean(key, value)
is String -> putString(key, value)
is Long -> putLong(key, value)
is Float -> putFloat(key, value)
is Parcelable -> putString(key, gson.toJson(value))
else -> throw Throwable("no such type exist to put data")
}
}
}
fun getPrefs(): T {
return when (newData) {
is Int -> sharedPrefs.getInt(key, 0) as T
is Boolean -> sharedPrefs.getBoolean(key, false) as T
is String -> sharedPrefs.getString(key, "") as T ?: "" as T
is Long -> sharedPrefs.getLong(key, 0L) as T
is Float -> sharedPrefs.getFloat(key, 0.0f) as T
is Parcelable -> gson.fromJson(sharedPrefs.getString(key, "") ?: "", T::class.java)
else -> throw Throwable("no such type exist to put data")
} ?: newData
}
}
//use this delegation in activity and fragment in following way
var ourData by sharedPrefs<String>("otherDatas")
你还没有说明在这之后你对prefsEditor对象做了什么,但是为了持久化首选项数据,你还需要使用:
prefsEditor.commit();
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
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);