Create application plugin

[swordfish]

I have created a Qt application (it uses R for running analyses). I want to make the application extendable using application plugins - in the sense, I want to allow anyone to make a new analysis (say linear-regression), with it's own user interface and an r package. How do I make this into a plugin?

In the future, I want to be able to download the new "analysis-plugin" (maybe from an app store) and my qt application should be able to run it. How do I do this?

Currently I just ship all the analyses in each release.

[raven-worx]

@swordfish
First read this

Then you need to think about a (robust) generic abstract interface which each plugin need to implement.
Also the link from above says:

1. Define a set of interfaces (classes with only pure virtual functions) used to talk to the plugins.
2. Use the Q_DECLARE_INTERFACE() macro to tell Qt's meta-object system about the interface.
3. Use QPluginLoader in the application to load the plugins.
4. Use qobject_cast() to test whether a plugin implements a given interface.

You can use QPluginLoader to load plugins from a custom folder name which then needs to rely next to the Qt plugins (somewhere in the import paths).

The interface class can have methods like:

class MyInterface
{
public:
    virtual ~MyInterface() {}

    virtual QWidget* getGui() const = 0;
    virtual void calculate() = 0;

    ..... whatever information the application needs
};

[mrjj]

Hi
Also for my first attempt i used
http://doc.qt.io/qt-5/qtwidgets-tools-echoplugin-example.html

which is pretty small and easy to understand.