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
你可以保存对象在首选项不使用任何库,首先你的对象类必须实现Serializable:
public class callModel implements Serializable {
private long pointTime;
private boolean callisConnected;
public callModel(boolean callisConnected, long pointTime) {
this.callisConnected = callisConnected;
this.pointTime = pointTime;
}
public boolean isCallisConnected() {
return callisConnected;
}
public long getPointTime() {
return pointTime;
}
}
然后你可以很容易地使用这两个方法来转换对象到字符串和字符串到对象:
public static <T extends Serializable> T stringToObjectS(String string) {
byte[] bytes = Base64.decode(string, 0);
T object = null;
try {
ObjectInputStream objectInputStream = new ObjectInputStream(new ByteArrayInputStream(bytes));
object = (T) objectInputStream.readObject();
} catch (Exception e) {
e.printStackTrace();
}
return object;
}
public static String objectToString(Parcelable object) {
String encoded = null;
try {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
objectOutputStream.writeObject(object);
objectOutputStream.close();
encoded = new String(Base64.encodeToString(byteArrayOutputStream.toByteArray(), 0));
} catch (IOException e) {
e.printStackTrace();
}
return encoded;
}
保存:
SharedPreferences mPrefs = getPreferences(MODE_PRIVATE);
Editor prefsEditor = mPrefs.edit();
prefsEditor.putString("MyObject", objectToString(callModelObject));
prefsEditor.commit();
阅读
String value= mPrefs.getString("MyObject", "");
MyObject obj = stringToObjectS(value);
其他回答
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
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)
}
}
// 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:)
这么多好答案,她是我的2美分
我更喜欢使用内联函数和旧风格的put和get值
object PreferenceHelper {
private const val PREFERENCES_KEY = "MyLocalPreference"
private fun getPreference(context: Context): SharedPreferences {
return context.getSharedPreferences(
PREFERENCES_KEY,
Context.MODE_PRIVATE
)
}
fun setBoolean(appContext: Context, key: String?, value: Boolean?) =
getPreference(appContext).edit().putBoolean(key, value!!).apply()
fun setInteger(appContext: Context, key: String?, value: Int) =
getPreference(appContext).edit().putInt(key, value).apply()
fun setFloat(appContext: Context, key: String?, value: Float) =
getPreference(appContext).edit().putFloat(key, value).apply()
fun setString(appContext: Context, key: String?, value: String?) =
getPreference(appContext).edit().putString(key, value).apply()
// To retrieve values from shared preferences:
fun getBoolean(appContext: Context, key: String?, defaultValue: Boolean?): Boolean =
getPreference(appContext).getBoolean(key, defaultValue!!)
fun getInteger(appContext: Context, key: String?, defaultValue: Int): Int =
getPreference(appContext)
.getInt(key, defaultValue)
fun getString(appContext: Context, key: String?, defaultValue: String?): String? =
getPreference(appContext)
.getString(key, defaultValue)
}
使用
PreferenceHelper.setString(context,"CUSTOMER_NAME", "HITESH")
Toast.makeText(context, "Hello " + PreferenceHelper.getString(context,"CUSTOMER_NAME", "User"), Toast.LENGTH_LONG).show()
将数据存储在SharedPreference中
SharedPreferences mprefs = getSharedPreferences(AppConstant.PREFS_NAME, MODE_PRIVATE)
mprefs.edit().putString(AppConstant.USER_ID, resUserID).apply();