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Add GtkDirecoryList.

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Toshio Sekiya 2021-03-16 00:10:38 +09:00
parent 8cfc7d4721
commit 126e3624b6
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169
gfm/sec24.md
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@ -324,4 +324,173 @@ GtkSingleSelection is used, so user can select one item at a time.
Because this is a small program, the ui data is given as strings.
However, generally, ui file is better than string and using resource compiler is the best choice.
## GtkDirectoryList
GtkDirectoryList is a list model containing GFileInfo objects which are information of files under a certain directory.
It uses `g_file_enumerate_children_async()` to get the GFileInfo objects.
The list model is created by `gtk_directory_list_new` function.
~~~C
GtkDirectoryList *gtk_directory_list_new (const char *attributes, GFile *file);
~~~
`attributes` is a comma separated list of file attributes.
File attributes are key-value pairs.
A key consists of a namespace and a name.
For example, "standard::name" key is the name of a file.
"standard" means general file information.
"name" means filename.
The following table shows some example.
|key |meaning |
|:---------------|:-------------------------------------------------------------------|
|standard::type |file type. for example, regular file, directory, symbolic link, etc.|
|standard::name |filename |
|standard::size |file size in bytes |
|access::can-read|read privilege if the user is able to read the file |
|time::modified |the time the file was last modified in seconds since the UNIX epoch |
The current directory is ".".
The following program makes GtkDirectoryList `dl` and its contents are GFileInfo objects under the current directory.
~~~C
GFile *file = g_file_new_for_path (".");
GtkDirectoryList *dl = gtk_directory_list_new ("standard::name", file);
g_object_unref (file);
~~~
It is not so difficult to make file listing program by changing `list2.c` in the previous subsection.
One problem is that GInfoFile doesn't have properties.
Lookup tag look for a property, so it is useless for looking for a filename from a GFileInfo object.
Instead, closure tag is appropriate in this case.
Closure tag specifies a function and the type of the return value of the function.
~~~C
char *
get_file_name (GtkListItem *item, GFileInfo *info) {
if (! G_IS_FILE_INFO (info))
return NULL;
else
return g_strdup (g_file_info_get_name (info));
}
... ...
... ...
"<interface>"
"<template class=\"GtkListItem\">"
"<property name=\"child\">"
"<object class=\"GtkLabel\">"
"<binding name=\"label\">"
"<closure type=\"gchararray\" function=\"get_file_name\">"
"<lookup name=\"item\">GtkListItem</lookup>"
"</closure>"
"</binding>"
"</object>"
"</property>"
"</template>"
"</interface>"
~~~
- "gchararray" is the type of strings.
"gchar" is the same as "char" type.
Therefore, "gchararray" is "an array of char type", which is the same as string type.
It is used to get the type of GValue object.
GValue is a generic value and it can contain various type of values.
For example, the type can be gboolean, gchar (char), gint (int), gfloat (float), gdouble (double), gchararray (char *) and so on.
For the further information, refer to GFileAttribute and GFileInfo section in [GIO API reference](https://developer.gnome.org/gio/stable/).
- closure tag has type attribute and function attribute.
Function attribute specifies a function name and type attribute specifies the type of the return value of the function.
The contents of closure tag (it is between \<closure...\> and\</closure\>) is parameters of the function.
`<lookup name=\"item\">GtkListItem</lookup>` gives two parameters.
The first parameter is GListItem object and the second parameter is item property, which is a GFileInfo object in the GtkDirectoryList Object.
- `gtk_file_name` function first check the `info` parameter.
Because it can be NULL when GListItem `item` is unbound.
If its GFileInfo, then return the filename (copy of the filename).
The whole program (`list3.c`) is as follows.
The program is located in [src/misc](../src/misc) directory.
~~~C
1 #include <gtk/gtk.h>
2
3 char *
4 get_file_name (GtkListItem *item, GFileInfo *info) {
5 if (! G_IS_FILE_INFO (info))
6 return NULL;
7 else
8 return g_strdup (g_file_info_get_name (info));
9 }
10
11 /* ----- activate, open, startup handlers ----- */
12 static void
13 tfe_activate (GApplication *application) {
14 GtkApplication *app = GTK_APPLICATION (application);
15 GtkWidget *win = gtk_application_window_new (app);
16 gtk_window_set_default_size (GTK_WINDOW (win), 600, 400);
17 GtkWidget *scr = gtk_scrolled_window_new ();
18 gtk_window_set_child (GTK_WINDOW (win), scr);
19
20 GFile *file = g_file_new_for_path (".");
21 GtkDirectoryList *dl = gtk_directory_list_new ("standard::name", file);
22 g_object_unref (file);
23 GtkNoSelection *ns = gtk_no_selection_new (G_LIST_MODEL (dl));
24
25 const char *ui_string =
26 "<interface>"
27 "<template class=\"GtkListItem\">"
28 "<property name=\"child\">"
29 "<object class=\"GtkLabel\">"
30 "<binding name=\"label\">"
31 "<closure type=\"gchararray\" function=\"get_file_name\">"
32 "<lookup name=\"item\">GtkListItem</lookup>"
33 "</closure>"
34 "</binding>"
35 "</object>"
36 "</property>"
37 "</template>"
38 "</interface>"
39 ;
40 GBytes *gbytes = g_bytes_new_static (ui_string, strlen (ui_string));
41 GtkListItemFactory *factory = gtk_builder_list_item_factory_new_from_bytes (NULL, gbytes);
42
43 GtkWidget *lv = gtk_list_view_new (GTK_SELECTION_MODEL (ns), factory);
44 gtk_list_view_set_enable_rubberband (GTK_LIST_VIEW (lv), TRUE);
45 gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), lv);
46 gtk_widget_show (win);
47 }
48
49 static void
50 tfe_startup (GApplication *application) {
51 }
52
53 /* ----- main ----- */
54 int
55 main (int argc, char **argv) {
56 GtkApplication *app;
57 int stat;
58
59 app = gtk_application_new ("com.github.ToshioCP.list2", G_APPLICATION_FLAGS_NONE);
60
61 g_signal_connect (app, "startup", G_CALLBACK (tfe_startup), NULL);
62 g_signal_connect (app, "activate", G_CALLBACK (tfe_activate), NULL);
63
64 stat =g_application_run (G_APPLICATION (app), argc, argv);
65 g_object_unref (app);
66 return stat;
67 }
68
~~~
Compile and execute it.
~~~
$ cd misc
$ comp list3
$ ./a.out
~~~
![screenshot list3](../image/list3.png)
Up: [Readme.md](../Readme.md), Prev: [Section 23](sec23.md)

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3
src/misc/comp
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@ -1 +1,2 @@
gcc `pkg-config --cflags gtk4` $1.c `pkg-config --libs gtk4`
gcc -Wl,--export-dynamic `pkg-config --cflags gtk4` $1.c `pkg-config --libs gtk4`

68
src/misc/list3.c Normal file
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@ -0,0 +1,68 @@
#include <gtk/gtk.h>
char *
get_file_name (GtkListItem *item, GFileInfo *info) {
if (! G_IS_FILE_INFO (info))
return NULL;
else
return g_strdup (g_file_info_get_name (info));
}
/* ----- activate, open, startup handlers ----- */
static void
tfe_activate (GApplication *application) {
GtkApplication *app = GTK_APPLICATION (application);
GtkWidget *win = gtk_application_window_new (app);
gtk_window_set_default_size (GTK_WINDOW (win), 600, 400);
GtkWidget *scr = gtk_scrolled_window_new ();
gtk_window_set_child (GTK_WINDOW (win), scr);
GFile *file = g_file_new_for_path (".");
GtkDirectoryList *dl = gtk_directory_list_new ("standard::name", file);
g_object_unref (file);
GtkNoSelection *ns = gtk_no_selection_new (G_LIST_MODEL (dl));
const char *ui_string =
"<interface>"
"<template class=\"GtkListItem\">"
"<property name=\"child\">"
"<object class=\"GtkLabel\">"
"<binding name=\"label\">"
"<closure type=\"gchararray\" function=\"get_file_name\">"
"<lookup name=\"item\">GtkListItem</lookup>"
"</closure>"
"</binding>"
"</object>"
"</property>"
"</template>"
"</interface>"
;
GBytes *gbytes = g_bytes_new_static (ui_string, strlen (ui_string));
GtkListItemFactory *factory = gtk_builder_list_item_factory_new_from_bytes (NULL, gbytes);
GtkWidget *lv = gtk_list_view_new (GTK_SELECTION_MODEL (ns), factory);
gtk_list_view_set_enable_rubberband (GTK_LIST_VIEW (lv), TRUE);
gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), lv);
gtk_widget_show (win);
}
static void
tfe_startup (GApplication *application) {
}
/* ----- main ----- */
int
main (int argc, char **argv) {
GtkApplication *app;
int stat;
app = gtk_application_new ("com.github.ToshioCP.list2", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "startup", G_CALLBACK (tfe_startup), NULL);
g_signal_connect (app, "activate", G_CALLBACK (tfe_activate), NULL);
stat =g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return stat;
}

102
src/sec24.src.md
View file

@ -203,3 +203,105 @@ GtkSingleSelection is used, so user can select one item at a time.
Because this is a small program, the ui data is given as strings.
However, generally, ui file is better than string and using resource compiler is the best choice.
## GtkDirectoryList
GtkDirectoryList is a list model containing GFileInfo objects which are information of files under a certain directory.
It uses `g_file_enumerate_children_async()` to get the GFileInfo objects.
The list model is created by `gtk_directory_list_new` function.
~~~C
GtkDirectoryList *gtk_directory_list_new (const char *attributes, GFile *file);
~~~
`attributes` is a comma separated list of file attributes.
File attributes are key-value pairs.
A key consists of a namespace and a name.
For example, "standard::name" key is the name of a file.
"standard" means general file information.
"name" means filename.
The following table shows some example.
|key |meaning |
|:---------------|:-------------------------------------------------------------------|
|standard::type |file type. for example, regular file, directory, symbolic link, etc.|
|standard::name |filename |
|standard::size |file size in bytes |
|access::can-read|read privilege if the user is able to read the file |
|time::modified |the time the file was last modified in seconds since the UNIX epoch |
The current directory is ".".
The following program makes GtkDirectoryList `dl` and its contents are GFileInfo objects under the current directory.
~~~C
GFile *file = g_file_new_for_path (".");
GtkDirectoryList *dl = gtk_directory_list_new ("standard::name", file);
g_object_unref (file);
~~~
It is not so difficult to make file listing program by changing `list2.c` in the previous subsection.
One problem is that GInfoFile doesn't have properties.
Lookup tag look for a property, so it is useless for looking for a filename from a GFileInfo object.
Instead, closure tag is appropriate in this case.
Closure tag specifies a function and the type of the return value of the function.
~~~C
char *
get_file_name (GtkListItem *item, GFileInfo *info) {
if (! G_IS_FILE_INFO (info))
return NULL;
else
return g_strdup (g_file_info_get_name (info));
}
... ...
... ...
"<interface>"
"<template class=\"GtkListItem\">"
"<property name=\"child\">"
"<object class=\"GtkLabel\">"
"<binding name=\"label\">"
"<closure type=\"gchararray\" function=\"get_file_name\">"
"<lookup name=\"item\">GtkListItem</lookup>"
"</closure>"
"</binding>"
"</object>"
"</property>"
"</template>"
"</interface>"
~~~
- "gchararray" is the type of strings.
"gchar" is the same as "char" type.
Therefore, "gchararray" is "an array of char type", which is the same as string type.
It is used to get the type of GValue object.
GValue is a generic value and it can contain various type of values.
For example, the type can be gboolean, gchar (char), gint (int), gfloat (float), gdouble (double), gchararray (char *) and so on.
For the further information, refer to GFileAttribute and GFileInfo section in [GIO API reference](https://developer.gnome.org/gio/stable/).
- closure tag has type attribute and function attribute.
Function attribute specifies a function name and type attribute specifies the type of the return value of the function.
The contents of closure tag (it is between \<closure...\> and\</closure\>) is parameters of the function.
`<lookup name=\"item\">GtkListItem</lookup>` gives two parameters.
The first parameter is GListItem object and the second parameter is item property, which is a GFileInfo object in the GtkDirectoryList Object.
- `gtk_file_name` function first check the `info` parameter.
Because it can be NULL when GListItem `item` is unbound.
If its GFileInfo, then return the filename (copy of the filename).
The whole program (`list3.c`) is as follows.
The program is located in [src/misc](misc) directory.
@@@include
misc/list3.c
@@@
Compile and execute it.
~~~
$ cd misc
$ comp list3
$ ./a.out
~~~
![screenshot list3](../image/list3.png){width=6.04cm height=4.41cm}