- 论坛徽章:
- 0
|
Example 3-10. Reading Keyboard Events
SDL_Event event;
- /* Poll for events. SDL_PollEvent() returns 0 when there are no */
- /* more events on the event queue, our while loop will exit when */
- /* that occurs. */
- while( SDL_PollEvent( &event ) ){
- /* We are only worried about SDL_KEYDOWN and SDL_KEYUP events */
- switch( event.type ){
- case SDL_KEYDOWN:
- printf( "Key press detected\n" );
- break;
- case SDL_KEYUP:
- printf( "Key release detected\n" );
- break;
- default:
- break;
- }
- }
复制代码
- #include "SDL.h"
- /* Function Prototypes */
- void PrintKeyInfo( SDL_KeyboardEvent *key );
- void PrintModifiers( SDLMod mod );
- /* main */
- int main( int argc, char *argv[] ){
-
- SDL_Event event;
- int quit = 0;
-
- /* Initialise SDL */
- if( SDL_Init( SDL_INIT_VIDEO ) ){
- fprintf( stderr, "Could not initialise SDL: %s\n", SDL_GetError() );
- exit( -1 );
- }
- /* Set a video mode */
- if( !SDL_SetVideoMode( 320, 200, 0, 0 ) ){
- fprintf( stderr, "Could not set video mode: %s\n", SDL_GetError() );
- SDL_Quit();
- exit( -1 );
- }
- /* Enable Unicode translation */
- SDL_EnableUNICODE( 1 );
- /* Loop until an SDL_QUIT event is found */
- while( !quit ){
- /* Poll for events */
- while( SDL_PollEvent( &event ) ){
-
- switch( event.type ){
- /* Keyboard event */
- /* Pass the event data onto PrintKeyInfo() */
- case SDL_KEYDOWN:
- case SDL_KEYUP:
- PrintKeyInfo( &event.key );
- break;
- /* SDL_QUIT event (window close) */
- case SDL_QUIT:
- quit = 1;
- break;
- default:
- break;
- }
- }
- }
- /* Clean up */
- SDL_Quit();
- exit( 0 );
- }
- /* Print all information about a key event */
- void PrintKeyInfo( SDL_KeyboardEvent *key ){
- /* Is it a release or a press? */
- if( key->type == SDL_KEYUP )
- printf( "Release:- " );
- else
- printf( "Press:- " );
- /* Print the hardware scancode first */
- printf( "Scancode: 0x%02X", key->keysym.scancode );
- /* Print the name of the key */
- printf( ", Name: %s", SDL_GetKeyName( key->keysym.sym ) );
- /* We want to print the unicode info, but we need to make */
- /* sure its a press event first (remember, release events */
- /* don't have unicode info */
- if( key->type == SDL_KEYDOWN ){
- /* If the Unicode value is less than 0x80 then the */
- /* unicode value can be used to get a printable */
- /* representation of the key, using (char)unicode. */
- printf(", Unicode: " );
- if( key->keysym.unicode < 0x80 && key->keysym.unicode > 0 ){
- printf( "%c (0x%04X)", (char)key->keysym.unicode,
- key->keysym.unicode );
- }
- else{
- printf( "? (0x%04X)", key->keysym.unicode );
- }
- }
- printf( "\n" );
- /* Print modifier info */
- PrintModifiers( key->keysym.mod );
- }
- /* Print modifier info */
- void PrintModifiers( SDLMod mod ){
- printf( "Modifers: " );
- /* If there are none then say so and return */
- if( mod == KMOD_NONE ){
- printf( "None\n" );
- return;
- }
- /* Check for the presence of each SDLMod value */
- /* This looks messy, but there really isn't */
- /* a clearer way. */
- if( mod & KMOD_NUM ) printf( "NUMLOCK " );
- if( mod & KMOD_CAPS ) printf( "CAPSLOCK " );
- if( mod & KMOD_LCTRL ) printf( "LCTRL " );
- if( mod & KMOD_RCTRL ) printf( "RCTRL " );
- if( mod & KMOD_RSHIFT ) printf( "RSHIFT " );
- if( mod & KMOD_LSHIFT ) printf( "LSHIFT " );
- if( mod & KMOD_RALT ) printf( "RALT " );
- if( mod & KMOD_LALT ) printf( "LALT " );
- if( mod & KMOD_CTRL ) printf( "CTRL " );
- if( mod & KMOD_SHIFT ) printf( "SHIFT " );
- if( mod & KMOD_ALT ) printf( "ALT " );
- printf( "\n" );
- }
复制代码 不想直接用的话可以读libsdl的源代码,看看是怎么实现的。 |
|