Advanced search
Jan. 21, 2019, 10:28 a.m.
Mihailll

QtВзаимодействие различных dll библиотек С++, C#, java

Добрый день. Почему работая на С++, нельзя полноценно использовать dll , написанных на C#, java? И почему используя другие языки, можно использовать dll , написанных на C++?

AndroidA little about memory leaks and ways to avoid them

Dec. 27, 2018, 12:53 a.m.

Memory leaks, garbage collection, Java

What is memory Leaks in Android development ?

The application creates objects, they lie in memory and can not clean out after the completion of its work.

Why is this happening ?

Java has its own means of clearing memory from unused items. This is garbage collection .

The garbage collector marks all objects that can be deleted if they are not referenced. Memory leak - this is just a lost reference, which shows that the object can not be deleted.

The complexity of this bug is that until a certain time it is not visible and it can not interfere.
There's a good quote from Benjamin Franklin: “A small leak will sink a great ship."
Memory leaks take the RAM of the application. The amount of raw memory will grow and may one day cause your app to slow down and crash . This will lead to user dissatisfaction and most likely the app will be removed...

x
Dec. 12, 2018, 10:28 a.m.
xintrea

JavaОтправка Email из Java окружения в Qt

Как выяснилось в этом обсуждении:

Отправка Email из Android в Qt

для отправки Email в Android необходимо делать Java-метод, который и будет отправлять email. И этот Java-метод надо дергать из C++ окружения.

Начал я его делать (за основу можно взять пример взаимодействи…

JavaSeveral ways to synchronize processes and threads in Java

Nov. 28, 2018, 12:58 p.m.

Java, synchronization, threads, processes

I propose to consider several ways to synchronize threads and processes that are most commonly used in Java. They differ in implementation and use cases. We will consider all methods on interesting examples.

Critical section

This method is suitable for you if:

  • parallel threads work with a shared resource;
  • requires synchronization between threads, not processes;

This method of synchronization is called resource synchronization ("open – close" synchronization). The idea of this method is that each object in Java has an associated monitor . A monitor is a kind of tool to control access to an object.

JavaExample - Object Pool in Java

Example of the design pattern An object pool in the Java programming language.

JavaExample - Factory Method in Java

In class-based programming, the factory method pattern is a creational pattern that uses factory methods to deal with the problem of creating objects without having to specify the exact class of the object that will be created. This is done by creating objects by calling a factory method—either specified in an interface and implemented by child classes, or implemented in a base class and optionally overridden by derived classes—rather than by calling a constructor.

JavaExample - "Builder" design pattern in Java

Example of "Builder" design pattern in Java

JavaExample - Abstract Factory in Java

Sept. 17, 2018, 8:47 a.m.

abstract, Java

Abstract Factory classes are often implemented with Factory Methods, but they can also be implemented using Prototype. Abstract Factory might store a set of Prototypes from which to clone and return product objects.

  • Factory Method: creation through inheritance.
  • Prototype: creation through delegation.
  • Virtual constructor: defer choice of object to create until run-time.

JavaImplementation of the Wave algorithm (Lee algorithm) in Java

Sometimes there is a problem to find the minimum path from point A to point B . The map can have barriers and be like a labyrinth. Similar tasks can be done in game development, PCB design and GPS development, etc.

There is a large set of algorithms for finding the minimum path. The most simple and effective is the Wave trace Algorithm (Lee algorithm). Which is based on the methods of breadth-first search.

This algorithm is not difficult to understand. It will be understandable even for a beginner in programming.

How to become an author?

Contribute to the evolution of the EVILEG community.

Learn how to become a site author.

Learn it
Donate

Good day, Dear Users!!!

I am Evgenii Legotckoi, developer of EVILEG. And it is my hobby project, which helps to learn programming another programmers and developers

If the site helped you, and you want also support the development of the site, than you can donate by following ways

PayPalYandex.Money
Timeweb

Let me recommend you the excellent hosting on which EVILEG is located.

For many years, Timeweb has been proving his stability.

For projects on Django I recommend VDS hosting

View Hosting Timeweb
s
June 3, 2020, 1:56 a.m.
silo1995

C++ - Тест 003. Условия и циклы

  • Result:35points,
  • Rating points-10
AP
June 2, 2020, 9:11 p.m.
Aleksej Pikenin

C++ - Test 005. Structures and Classes

  • Result:75points,
  • Rating points2
June 2, 2020, 1:04 p.m.
Daniil Chizhevskij

C++ - Test 001. The first program and data types

  • Result:86points,
  • Rating points6
Last comments
s
June 3, 2020, 2:33 p.m.
safevgeniia

Qt/C++ - Lesson 036. QWebView – How to make simple browser on the Qt

я с учетом обновлений использовала webenginewidgets
s
June 3, 2020, 2:32 p.m.
safevgeniia

Qt/C++ - Lesson 036. QWebView – How to make simple browser on the Qt

я с учетом обновлений использовала webenginewidgets
June 3, 2020, 2:25 p.m.
Mihailll

Qt/C++ - Lesson 036. QWebView – How to make simple browser on the Qt

Если взяли все из примера, то не должно собраться, т.к. webkit webkitwidgets уже не работают. Какой класс Вы используете для браузера?
s
June 3, 2020, 2 p.m.
safevgeniia

Qt/C++ - Lesson 036. QWebView – How to make simple browser on the Qt

Вроде вск записала правильно, все подключила . Проблем со сборко нет. НО вместо сайта выводится белый экран просто. В чем проблема может быть? По задумке, при нажатии на кнопку долже…
MA
June 3, 2020, 11:40 a.m.
Mihail A

Qt/C++ - Lesson 050. Logging Qt application events to a text file

Как только переношу в класс метод messageHandler, он подчеркнут ошибкой в конструкторе: qInstallMessageHandler(messageHandler); Сам метод в классе называется уже: void Customers::mess…
Now discuss on the forum
June 3, 2020, 2:34 a.m.
Evgenij Legotskoj

Qt- C++ QTableView подсветить строку

Некогда было
f
June 3, 2020, 1:49 a.m.
fryn3

Можно ли сделать в QML таблицу как в Excel?

edi-tableview - нашел пока такое выглядит коряво, посмотрим что можно сделать
June 2, 2020, 2:46 a.m.
Evgenij Legotskoj

Медиа файлы Google Firebase

Картинки можете попробовать сжимать через QPixmap, там есть возможность установки scaleFactor, через него можете устанавливать нужные параметры. А что касается конвертации видео, то лучше п…
June 2, 2020, 2:01 a.m.
Evgenij Legotskoj

Перехват обращения к локальным файлам QWebEngineView

В вашем случае вполне адекватное решение. Так сказать меньше зло. В противном случае пришлось бы очень много переписывать и перепиливать.
a
June 1, 2020, 10:26 a.m.
alekseyttrv

SSL на Android

у меня стоит версия Qt 5.14.2. В настройках android поставил openssl из коробки, и этот прроект автоматически стянулся. Достаточно было только добавить в .pro-файл строку после этого и все …
About
Services
© EVILEG 2015-2020
Recommend hosting TIMEWEB