【GObject-02】Signal

最新推荐文章于 2023-07-07 22:55:42 发布

TimeTravelo

最新推荐文章于 2023-07-07 22:55:42 发布

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分类专栏： gobject 文章标签： gobject

本文链接：https://blog.youkuaiyun.com/qq_21955665/article/details/117223838

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本文主要介绍了GObject的信号机制，包括基本使用方法和一些进阶应用。通过示例代码`signal_demo.h`、`signal_demo.c`和`main.c`，展示了如何在实际项目中应用信号。虽然目前的进阶使用部分为空，但文章提供了学习和理解GObject信号的基础。

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基本使用

signal_demo.h

#ifndef SIGNAL_DEMO_H
#define SIGNAL_DEMO_H
  
#include <glib-object.h>
  
#define SIGNAL_TYPE_DEMO (signal_demo_get_type ())
#define SIGNAL_DEMO(object) \
        G_TYPE_CHECK_INSTANCE_CAST ((object), SIGNAL_TYPE_DEMO, SignalDemo)
#define SIGNAL_IS_DEMO(object) \
        G_TYPE_CHECK_INSTANCE_TYPE ((object), SIGNAL_TYPE_DEMO))
#define SIGNAL_DEMO_CLASS(klass) \
        (G_TYPE_CHECK_CLASS_CAST ((klass), SIGNAL_TYPE_DEMO, SignalDemoClass))
#define SIGNAL_IS_DEMO_CLASS(klass) \
        (G_TYPE_CHECK_CLASS_TYPE ((klass), SIGNAL_TYPE_DEMO))
#define SIGNAL_DEMO_GET_CLASS(object) (\
                G_TYPE_INSTANCE_GET_CLASS ((object), SIGNAL_TYPE_DEMO, SignalDemoClass))
  
typedef struct _SignalDemo SignalDemo;
struct _SignalDemo {
    GObject parent;
};
  
typedef struct _SignalDemoClass SignalDemoClass;
struct _SignalDemoClass {
        GObjectClass parent_class;
        void (*default_handler) (gpointer instance, const gchar *buffer, gpointer userdata);
};
  
GType signal_demo_get_type (void);
 
#endif

signal_demo.c

#include "signal_demo.h"
 
G_DEFINE_TYPE (SignalDemo, signal_demo, G_TYPE_OBJECT);
 
static void
signal_demo_default_handler (gpointer instance, const gchar *buffer, gpointer userdata)
{
        g_print ("Default handler said: %s\n", buffer);
}
 
void
signal_demo_init (SignalDemo *self)
{
}
 
void
signal_demo_class_init (SignalDemoClass *klass)
{
        klass->default_handler = signal_demo_default_handler;
        g_signal_new("hello",              /*信号名字*/
                G_TYPE_FROM_CLASS(klass),  /*类型ID,(1)G_TYPE_FROM_CLASS获取； (2) 直接使用 SIGNAL_TYPE_DEMO 宏 */   
                G_SIGNAL_RUN_FIRST,        /*信号的调用顺序*/
                G_STRUCT_OFFSET(SignalDemoClass, default_handler), /*内存偏移量，为了找到default handler的位置*/
                NULL,
                NULL,
                g_cclosure_marshal_VOID__STRING,/*闭包，marshal函数的描述*/
                G_TYPE_NONE,                    /*marshal函数的返回值类型*/
                1,                              /*g_signal_new 函数向 marshal 函数传递的参数个数*/
                G_TYPE_STRING);                 /*g_signal_new 函数向 marshal 函数传递的参数类型*/
}

main.c

#include <stdio.h>
#include "signal_demo.h"

static void
my_signal_handler (gpointer *instance, gchar *buffer, gpointer userdata)
{
        g_print ("my_signal_handler said: %s\n", buffer);
        g_print ("my_signal_handler said: %s\n", (gchar *)userdata);
}
 


int main()
{
    // g_type_init ();

    gchar *userdata = "This is userdata";
    SignalDemo *sd_obj = g_object_new (SIGNAL_TYPE_DEMO, NULL);

    /* 信号连接 */
    g_signal_connect (sd_obj, "hello", 
                        G_CALLBACK (my_signal_handler), 
                        userdata);

    /* 发射信号 */
    g_signal_emit_by_name (sd_obj, 
                            "hello", 
                            "This is the second param", 
                            G_TYPE_NONE);
    // HOME_CLASS(pHome).
    while(1);
    return 0;
}

进阶使用

暂时没遇到，先空这里