GTK + graphical Application Development Learning notes

Http://blog.chinaunix.net/u/22935/showart_305786.html
I. InitializationGTK +

WriteGTK +ProgramNeed to callGtk_initFunction pairGTK +Library Function initialization.

1.

Name::	Gtk_init
Function:	InitializationGTK +Library
Header file:	# Include <GTK/GTK. h>
Function prototype:	Void gtk_init (int * argc, char *** argv );
Parameters:	ArgcPointing to Main FunctionArgcPointer ArgvPointing to Main FunctionArgvPointer
Return Value:	None

 

 

 

 When your program usesGTK +Before the tool library, you must initialize it.Gtk_initCan be initializedGTK +Tool library.Gtk_initTo the main function.Argc, argvPointer, it can change some does not meetGTK +The command line parameters required by the function.

BecauseGtk_initThe function does not return values. Therefore, if an error occurs during initialization, the program exits immediately.

2.

Name::	Gtk_init_check
Function:	InitializationGTK +Library
Header file:	# Include <GTK/GTK. h>
Function prototype:	Gboolean gtk_init_check (int * argc, char *** argv );
Parameters:	ArgcPointing to Main FunctionArgcPointer ArgvPointing to Main FunctionArgvPointer
Return Value:	Return successfulTure, Error returnedFalse.

 

 

 

 There is anotherGTK +Library initialization FunctionGtk_init_check, Its role andGtk_initIdentical. The only difference is thatGtk_init_checkIf there is a return value, you can determine whether the initialization is successful.

 

2. Create a window

GTK +The component isGui. Windows, check boxes, buttons, and editing fields are all components. Usually, components and windows are defined as pointingGtkwidgetStructure pointer. InGTK +Medium,GtkwidgetIs a common data type used for all components and windows.

GTK +After the library is initialized, most applications create a main window. InGTK +The main window is often called a top-level window. The top-level window is not included in any other window, so it has no upper-level window. InGTK +The component has a parent-child relationship. The parent component is a container, and the child component is a component contained in the container. The top-level window does not have a parent window, but it may Become a container of other components.

InGTK +Build a component in two steps: Create a component and make it visible.Gtk_window_newThe function is responsible for creating a window.Gtk_widget_showThe function is responsible for making it visible.

2.

name : :	gtk_window_new
function :	Create a window
header file :	# include
function prototype :	gtkwidget * gtk_window_new (
parameter :
return value :

 

 

 

 

 

 

 

 

3.

name : :	gtk_widget_show
function :	display window
header file :	# include
function prototype :	gtk_widget_show (gtkwidget * window)
parameter :
return value :

 

 

 

 

 

 

 

 

 

III,GTK +Event Loop

PairGTK +After initializing and placing the window and component on the screen, the program callsGet_mainThe function waits for the execution of an event.

 

4.

Name::	Gtk_main
Function:	Wait for the occurrence of the event
Header file:	# Include <GTK/GTK. h>
Function prototype:	Void gtk_main (void );
Parameters:	None
Return Value:	None

 

 

 

 

Let's take a look at the procedure in Chapter 1. Maybe you will understand the functions above.

/* Base1.c */ # Include <GTK/GTK. h> Int main (INT argc, char * argv []) { Gtkwidget * window;  Gtk_init (& argc, & argv );  Window = gtk_window_new (gtk_window_toplevel );  Gtk_widget_show (window );  Gtk_main ();  Return false; }

$ Gcc-O base1 base1.c 'pkg-config -- cflags -- libs GTK +-1000'

$./Base1

 

 

The program starts to define a form, and then uses the FunctionGtk_initInitializationGTK +Library. FunctionsGtk_window_newCreate a formGet_widget_showThis form is displayed. Program final callGtk_main ()Enter the main loop and wait for various events.

Note that the program cannot exit normally because the program does not have a call-back function. We will introduce the callback function below.

 

 

4. End the application

5.

name : :	gtk_main_quit
function :	end application
header file :	# include
function prototype :	void gtk_main_quit (void);
parameter :	none
return value :	none

Gtk_main_quitFunction can end the program It is usually called in the callback function. Next we will introduce the callback function.