用简单的方法来访问GObject对象的私有属性

这里只用到了最简单的方法，给我的感觉就是使用g_object_get/set函数来完成对已经安装的属性的存取工作。

目前我们还没有涉及到‘信号’这个NB的东西，连interface'接口'是什么，我也还没看到。

不过目前这点可怜的知识，能够对看懂gdk的源码产生一定的帮助了。

至少那些.h中的茫茫多的枚举和结构体的存在理由已经被我们找到了。

#include<glib-object.h>

#define SOME_OBJECT_TYPE		(some_object_get_type())
#define SOME_OBJECT(obj)		(G_TYPE_CHECK_INSTANCE_CAST((obj), SOME_OBJECT_TYPE, SomeObject))
#define SOME_IS_OBJECT(obj)		(GTYPE_CHECK_TYPE((obj), SOME_OBJECT_TYPE))
#define SOME_OBJECT_CLASS(c)		(G_TYPE_CHECK_CLASS_CAST((c), SOME_OBJECT_TYPE,SomeObjectClass))
#define SOME_IS_OBJECT_CLASS(c)		(G_TYPE_CHECK_CLASS_TYPE((c), SOME_OBJECT_TYPE))
#define SOME_OBJECT_GET_CLASS(obj)	(G_TYPE_INSTANCE_GET_CLASS((obj), SOME_OBJECT_TYPE, SomeObjectClass))
#define SOME_OBJECT_GET_PRIVATE(obj)	(G_TYPE_INSTANCE_GET_PRIVATE((obj), SOME_OBJECT_TYPE, SomeObjectPrivate))

typedef struct _SomeObject		SomeObject;
typedef struct _SomeObjectClass		SomeObjectClass;
typedef struct _SomeObjectPrivate	SomeObjectPrivate;

struct _SomeObject {
GObject parent_obj;
SomeObjectPrivate *priv;
};

struct _SomeObjectClass {
GObjectClass parent_class;
void (*born)(void);			// 出生
void (*grow)(SomeObject *self);		// 成长
};

struct _SomeObjectPrivate {
guint age;
gchar *name;
};

enum
{
OBJECT_PROPERTY_0,
OBJECT_PROPERTY_AGE,
OBJECT_PROPERTY_NAME,
OBJECT_PROPERTY_BORN,
OBJECT_PROPERTY_GROW
};

void some_object_grow(SomeObject *self);
void some_object_give_name(SomeObject *self, gchar *name);

G_DEFINE_TYPE (SomeObject, some_object, G_TYPE_OBJECT)

void some_object_set_property(GObject *object, guint property_id, const GValue *value, GParamSpec *pspec)
{
SomeObject *self = SOME_OBJECT(object);

switch(property_id) {
case OBJECT_PROPERTY_AGE:
self->priv->age = g_value_get_uint(value);
g_print("%s age: %d.\n",__func__, self->priv->age);
break;
case OBJECT_PROPERTY_NAME:
g_free(self->priv->name);
self->priv->name = g_value_dup_string(value);
g_print("%s name: %s.\n", __func__, self->priv->name);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
break;
}
}

void some_object_get_property(GObject *object, guint property_id, GValue *value, GParamSpec *pspec)
{
SomeObject *self = SOME_OBJECT(object);

switch (property_id) {
case OBJECT_PROPERTY_AGE:
g_value_set_uint(value, self->priv->age);
break;
case OBJECT_PROPERTY_NAME:
g_value_set_string(value, self->priv->name);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
break;
}
}

static void born(void)
{
g_print("a object was born.\n");
}

static void grow(SomeObject *self)
{
guint age =0;
g_object_get(G_OBJECT(self), "property-age", &age, NULL);
age += 1;
g_object_set(G_OBJECT(self), "property-age", age, NULL);
}

void some_object_dispose(GObject *gobject)
{
SomeObject *slef = SOME_OBJECT(gobject);
g_print("-- %s # %i\n",__func__, __LINE__);
G_OBJECT_CLASS(some_object_parent_class)->dispose(gobject);
}

void some_object_finalize(GObject *gobject)
{
SomeObject *self = SOME_OBJECT(gobject);
g_free(self->priv->name);
g_print("-- %s # %i\n",__func__, __LINE__);
G_OBJECT_CLASS(some_object_parent_class)->finalize(gobject);
}

static void some_object_class_init(SomeObjectClass* g_class)
{
g_type_class_add_private(g_class, sizeof(SomeObjectPrivate));

GObjectClass *this_class = G_OBJECT_CLASS(g_class);
GParamSpec *spec;

g_print("-- %s # %i\n",__func__, __LINE__);
this_class->dispose = &some_object_dispose;
this_class->finalize = &some_object_finalize;
this_class->set_property = &some_object_set_property;
this_class->get_property = &some_object_get_property;

spec = g_param_spec_uint("property-age",
"the age",
"Set/Get age",
0,
150,
0,
G_PARAM_READWRITE);
g_object_class_install_property(this_class, OBJECT_PROPERTY_AGE, spec);
spec = g_param_spec_string("property-name",
"the name",
"Set/Get name",
"no-name-set",
G_PARAM_READWRITE);
g_object_class_install_property(this_class, OBJECT_PROPERTY_NAME, spec);
}

void some_object_init(SomeObject *self)
{
SomeObjectPrivate *priv;
born();
self->priv = priv = SOME_OBJECT_GET_PRIVATE(self);
priv->age = 0;
priv->name = g_strdup("no-name");
g_print("-- %s # %i\n",__func__, __LINE__);
g_object_set(G_OBJECT(self),"property-age",0,"property-name","no-name",NULL);
}

void some_object_grow(SomeObject *self)
{
grow(self);
guint age = 0;
g_object_get(G_OBJECT(self),"property-age", &age, NULL);
g_print("%s I'm %d years old.\n",__func__, age);
}

void some_object_give_name(SomeObject *self, gchar *name)
{
g_object_set(G_OBJECT(self), "property-name", name, NULL);
g_print("%s hi, my name is %s.\n",__func__, name);
}

int main()
{
g_print("****init the type system****\n");
g_type_init();
g_print("****init type system OK ****\n");
SomeObject *testobj = g_object_new(SOME_OBJECT_TYPE, NULL);;
some_object_give_name(testobj, "Tom");
some_object_grow(testobj);
some_object_grow(testobj);
some_object_grow(testobj);
g_object_unref(testobj);
g_print("****finish GObject Demo ****\n");
return 0;
}

Makefile:

all:
gcc `pkg-config --cflags --libs gobject-2.0` someobject.c -o test

输出结果：

****init the type system****
****init type system OK ****
-- some_object_class_init # 117
a object was born.
-- some_object_init # 146
some_object_set_property age: 0.
some_object_set_property name: no-name.
some_object_set_property name: Tom.
some_object_give_name hi, my name is Tom.
some_object_set_property age: 1.
some_object_grow I'm 1 years old.
some_object_set_property age: 2.
some_object_grow I'm 2 years old.
some_object_set_property age: 3.
some_object_grow I'm 3 years old.
-- some_object_dispose # 98
-- some_object_finalize # 106
****finish GObject Demo ****

虽然我们的技巧还很烂，不过能够交互了不是么，O(∩_∩)O哈哈哈~