Difference between revisions of "Building Plugins:HelloMyth"

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make install
make install

Revision as of 04:51, 7 January 2010

Time.png Outdated: The information on this page may no longer be relevant to the current release of MythTV, 31.0. Please consider helping to update it.

Creating Your First Plugin: Hello Myth

This is a really simple skeleton plugin that doesn't do anything. It'll show you what is absolutely necessary to create a plugin, then you can expand on that by dissecting others.

As a disclaimer, I am also very new to plugin development and so please correct me where I might be wrong.

To start, download the mythplugin directory from SVN and create the following directory tree within its:

svn co http://svn.mythtv.org/svn/trunk/mythplugins
mkdir -p mythplugins/mythhello/mythhello

You will also need to install some development tools if you don't already have them (qmake-qt4 for newer mythtv, or qmake for older versions). For example:

sudo apt-get install qt4-qmake

mythhello.pro Files

The *.pro files are used by qmake to create the Makefiles.

1) Create a file called mythhello.pro in the first mythhello directory:

TEMPLATE = subdirs

# Directories
SUBDIRS = mythhello

"mythhello" refers to the second mythhello directory.

2) Create another file called mythhello.pro in the second mythhello (mythplugins/mythhello/mythhello/mythhello.pro) directory

include ( ../../mythconfig.mak )
include ( ../../settings.pro )
QT += network sql xml
CONFIG += plugin thread
TARGET = mythhello
target.path = $${LIBDIR}/mythtv/plugins
INSTALLS += target

uifiles.path = $${PREFIX}/share/mythtv/themes/default
uifiles.files = hello-ui.xml
installfiles.path = $${PREFIX}/share/mythtv
installfiles.files = hello-ui.xml

INSTALLS += uifiles

# Input
HEADERS += mythhello.h
SOURCES += main.cpp mythhello.cpp

macx {
    QMAKE_LFLAGS += -flat_namespace -undefined suppress

The following items are specific to your plugin: 'uifiles.files', 'installfiles.files', 'HEADERS', 'SOURCES'. Be sure that $${LIBDIR} and $${PREFIX} are set in mythplugins/mythconfig.mak to be the mythtv install prefix and library directory. Mine are set to:


(Note: I didn't find a mythplugins/mythconfig.mak but adding the above two lines to the top of my mythhello.mak worked to set the paths correctly - using a 0.21 system.)

(Note2: You can execute the configure script in mythplugins to generate the mythconfig.mak file. Depending on where your mythtv is located it may be necessary to add the argument --prefix=/usr)

CPP Files

Now we create the cpp/h files which should be put in mythplugins/mythhello/mythhello/.


Here's the main file that takes care of initializing, running and destructing the pluigin:

// C++ headers
#include <unistd.h>

// QT headers
#include <QApplication>

// MythTV headers
#include <mythcontext.h>
#include <mythplugin.h>
#include <mythpluginapi.h>
#include <mythversion.h>
#include <mythmainwindow.h>

// MythHello headers
#include "mythhello.h"

using namespace std;

void runHello(void);
int  RunHello(void);

void setupKeys(void)
    REG_JUMP("MythHello", QT_TRANSLATE_NOOP("MythHello",
        "Sample plugin"), "", runHello);

int mythplugin_init(const char *libversion)
    if (!gContext->TestPopupVersion("mythhello",
        return -1;
    return 0;

void runHello(void)

int RunHello(void)
    MythScreenStack *mainStack = GetMythMainWindow()->GetMainStack();
    MythHello *mythhello = new MythHello(mainStack, "hello");
    if (mythhello->Create())
        return 0;
        delete mythhello;
        return -1;

int mythplugin_run(void)
    return RunHello();

int mythplugin_config(void)



// MythTV headers

#include <mythscreentype.h>
#include <mythuibutton.h>

/** \class MythHello
*  \brief Example plugin.  Shows how to use Text areas and buttons
class MythHello : public MythScreenType
        MythHello(MythScreenStack *parent, QString name);
        bool Create(void);
        bool keyPressEvent(QKeyEvent *);
        MythUIText *m_titleText;
        MythUIText *m_outText;
        MythUIButton   *m_cancelButton;
        MythUIButton   *m_okButton;

    private slots:
        void ok_clicked(void);
        void cancel_clicked(void);

#endif /* MYTHHELLO_H */


// POSIX headers
#include <unistd.h>

// MythTV headers
#include <mythuibutton.h>
#include <mythuitext.h>
#include <mythmainwindow.h>
#include <mythcontext.h>
#include <mythdirs.h>

// MythHello headers
#include "mythhello.h"

#define LOC      QString("MythHello: ")
#define LOC_WARN QString("MythHello, Warning: ")
#define LOC_ERR  QString("MythHello, Error: ")

/** \brief Creates a new MythHello Screen
*  \param parent Pointer to the screen stack
*  \param name The name of the window
MythHello::MythHello(MythScreenStack *parent, QString name) :
    MythScreenType(parent, name),

    //example of how to find the configuration dir currently used.
    QString confdir = GetConfDir();
    VERBOSE(VB_IMPORTANT, LOC + "Conf dir:"  + confdir);

bool MythHello::Create(void)
    bool foundtheme = false;

    // Load the theme for this screen
    foundtheme = LoadWindowFromXML("hello-ui.xml", "hello", this);
    if (!foundtheme)
        return false;
    bool err = false;
    UIUtilE::Assign(this, m_titleText, "title", &err);
    UIUtilE::Assign(this, m_outText, "outtext", &err);
    UIUtilE::Assign(this, m_cancelButton, "cancel", &err);
    UIUtilE::Assign(this, m_okButton, "ok", &err);

    if (err)
        VERBOSE(VB_IMPORTANT, "Cannot load screen 'hello'");
        return false;

    if (!BuildFocusList())
        "Failed to build a focuslist. Something is wrong");


    connect(m_okButton, SIGNAL(Clicked()), this, SLOT(ok_clicked()));
    connect(m_cancelButton, SIGNAL(Clicked()), this, SLOT(cancel_clicked()));

    return true;
bool MythHello::keyPressEvent(QKeyEvent *event)
    if (GetFocusWidget() && GetFocusWidget()->keyPressEvent(event))
        return true;
    bool handled = false;
    QStringList actions;
    handled = GetMythMainWindow()->TranslateKeyPress("Hello", event, actions);

    for (int i = 0; i < actions.size() && !handled; i++)
        QString action = actions[i];
        handled = true;

        if (action == "ESCAPE")
            handled = false;
    if (!handled && MythScreenType::keyPressEvent(event))
        handled = true;

    return handled;

void MythHello::ok_clicked(void)
    m_outText->SetText(QString("OK clicked"));

void MythHello::cancel_clicked(void)
    m_outText->SetText(QString("Cancel clicked"));

The UI File

What would a plugin be without a UI? Now create hello-ui.xml and put it in mythplugins/mythhello/mythhello/.

<?xml version="1.0" encoding="utf-8"?>

  <window name="hello">

    <font name="title" face="Arial">

    <container name="hello">

      <textarea name="title" draworder="1" align="center">
        <value>Hello MythTV!</value>




Go to the top mythhello directory (mythplugins/mythhello) and run these commands:

make install

Make sure everything compiled OK and the files where copied to your mythtv installation directories.

Important.png Note: For newer versions of MythTV, qmake should be replaced by qmake-qt4.

Adding MythHello to your Menus

As a final step you have to add your plugin to the main MythTv menu -- in my case /usr/share/mythtv/mainmenu.xml. Add the following anywhere in the XML file between the <mythmenu> root tag:

   <text>Hello Myth</text>
   <action>PLUGIN mythhello</action>

Finishing Up

Now restart MythFrontend and you should see a 'Hello Myth' button on the main menu.

Good Luck

- Mozmonkey

More about plugins

MythPlugin Architecture