将ProtoBuf对象存储在SharedReferences中

我想存储一个 ProtoBuf SharedPreferences . Protocol Buffers ByteString Byte Array 但是 共享引用

InvalidProtocolBufferException :

public static void setProtoData(ProtoData data) {
    Prefs.putString(Constants.SHARED_PREF_PROTO_DATA, String.valueOf(data.toByteString()));
}

public static ProtoData getProtoData() {
    String str = Prefs.getString(Constants.SHARED_PREF_PROTO_DATA, null);
    ProtoData data = null;

    try {
        data = ProtoData.parseFrom(ByteString.copyFromUtf8(str));
    } catch (InvalidProtocolBufferException e) {
        e.printStackTrace();
    }

    return data;
}