Building Plugins:HelloMyth
Contents
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 TEMPLATE = lib 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:
PREFIX=/usr/ LIBDIR=/usr/lib/
(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/.
main.cpp
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", libversion, MYTH_BINARY_VERSION)) return -1; setupKeys(); return 0; } void runHello(void) { RunHello(); } int RunHello(void) { MythScreenStack *mainStack = GetMythMainWindow()->GetMainStack(); MythHello *mythhello = new MythHello(mainStack, "hello"); if (mythhello->Create()) { mainStack->AddScreen(mythhello); return 0; } else { delete mythhello; return -1; } } int mythplugin_run(void) { return RunHello(); } int mythplugin_config(void) { }
mythhello.h
#ifndef MYTHHELLO_H #define MYTHHELLO_H // 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 { Q_OBJECT public: MythHello(MythScreenStack *parent, QString name); bool Create(void); bool keyPressEvent(QKeyEvent *); private: 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 */
mythhello.cpp
// 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), m_cancelButton(NULL) { //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()) { VERBOSE(VB_IMPORTANT, LOC_ERR + "Failed to build a focuslist. Something is wrong"); } SetFocusWidget(m_cancelButton); 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") Close(); else 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"?> <mythuitheme> <window name="hello"> <textarea name="title"> <area>0,10,800,100</area> <font>large</font> <align>allcenter</align> <multiline>yes</multiline> <value>Hello World</value> </textarea> <textarea name="outtext"> <area>0,300,800,100</area> <font>large</font> <align>allcenter</align> <multiline>yes</multiline> </textarea> <button name="cancel" from="basebutton"> <position>500,400</position> <value>Cancel</value> </button> <button name="ok" from="basebutton"> <position>200,400</position> <value>OK</value> </button> </window> </mythuitheme>
Building
Go to the top mythhello directory (mythplugins/mythhello) and run these commands:
su qmake-qt4 make make install
Make sure everything compiled OK and the files where copied to your mythtv installation directories.
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:
<button> <type>HELLO_MYTH</type> <text>Hello Myth</text> <action>PLUGIN mythhello</action> </button>
Finishing Up
Now restart MythFrontend and you should see a 'Hello Myth' button on the main menu.
Good Luck
- Mozmonkey