Error de NoSuchFieldException de gson: java, android, json, gson

Estoy tratando de convertir un objeto personalizado a JSON y luego guardarlo en SharedPreferences. Cuando intento hacer eso, la aplicación falla NoSuchFieldException error.

Aquí está el código:

User myUser= new User("a", "b", 2, getApplicationContext());
SharedPreferences.Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myUser);
prefsEditor.putString(myUser.getUserPhone(), json);
prefsEditor.commit();

Creo que el problema radica en el gson.toJson conversión, porque cuando lo comento la aplicación ya no se bloquea.

¿Cualquier sugerencia? Gracias

Logcat:

   java.lang.AssertionError: java.lang.NoSuchFieldException: ASCENDING
at com.google.gson.internal.bind.TypeAdapters$EnumTypeAdapter.<init>(TypeAdapters.java:791)
at com.google.gson.internal.bind.TypeAdapters$30.create(TypeAdapters.java:817)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory.create(CollectionTypeAdapterFactory.java:53)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.MapTypeAdapterFactory.create(MapTypeAdapterFactory.java:126)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
at com.google.gson.Gson.getAdapter(Gson.java:423)
at com.google.gson.Gson.toJson(Gson.java:661)
at com.google.gson.Gson.toJson(Gson.java:648)
at com.google.gson.Gson.toJson(Gson.java:603)

Respuestas

0 para la respuesta № 1

En primer lugar debes quitar el getApplicationContext() del constructor de User Class porque para json no se puede escribir el objeto de contexto.

User myUser= new User("a", "b", 2);
SharedPreferences.Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myUser);
prefsEditor.putString(myUser.getUserPhone(), json);
prefsEditor.commit();

si quieres usar el getApplicationContext() hacer otra secundaria constructor. Y asigne la palabra clave transitoria de contexto en la clase de usuario.

private transient Context context;

Si crea un campo en un transitorio de clase Java, GSON lo ignorará tanto en la serialización como en la deserialización.

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0 para la respuesta № 2

Para convertir su modelo u objeto en String usando Gson, debe seguir los siguientes pasos:

1er paso: asegúrese de que la dependencia de Gson se agregue a su archivo gradle de aplicación. (Si no se agrega, agregue como se indica a continuación.)

compile "com.google.code.gson:gson:2.8.2"

2do paso: tu clase modelo

public class ModelClass {

String name;
String number;

public ModelClass() {
}

public ModelClass(String name, String number, Context context) {
this.name = name;
this.number = number;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getNumber() {
return number;
}

public void setNumber(String number) {
this.number = number;
}
}

3er Paso: Finalmente, convierte tu modelo u objeto a String usando Gson

ModelClass modelClass=new ModelClass("abc","45465545",MainActivity.this); // here we pass three parameters to ModelClass. ( name, number and context )
Gson gson = new Gson();
String jsonString=gson.toJson(modelClass);

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