GtkTextView 是一个用于多行编辑的控件，GtkTextBuffer 是一个文本缓冲器，用于保存文本，可以连接到 GtkTextView。下面是程序 tfv1.c：
1 #include <gtk/gtk.h>
2
3 static void
4 app_activate (GApplication *app, gpointer user_data) {
5 GtkWidget *win;
6 GtkWidget *tv;
7 GtkTextBuffer *tb;
8 gchar *text;
9
10 text =
11 "Once upon a time, there was an old man who was called Taketori-no-Okina. "
12 "It is a japanese word that means a man whose work is making bamboo baskets.\n"
13 "One day, he went into a mountain and found a shining bamboo. "
14 "\"What a mysterious bamboo it is!,\" he said. "
15 "He cut it, then there was a small cute baby girl in it. "
16 "The girl was shining faintly. "
17 "He thought this baby girl is a gift from Heaven and took her home.\n"
18 "His wife was surprized at his tale. "
19 "They were very happy because they had no children. "
20 ;
21 win = gtk_application_window_new (GTK_APPLICATION (app));
22 gtk_window_set_title (GTK_WINDOW (win), "Taketori");
23 gtk_window_set_default_size (GTK_WINDOW (win), 400, 300);
24
25 tv = gtk_text_view_new ();
26 tb = gtk_text_view_get_buffer (GTK_TEXT_VIEW (tv));
27 gtk_text_buffer_set_text (tb, text, -1);
28 gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD_CHAR);
29
30 gtk_window_set_child (GTK_WINDOW (win), tv);
31
32 gtk_widget_show (win);
33 }
34
35 int
36 main (int argc, char **argv) {
37 GtkApplication *app;
38 int stat;
39
40 app = gtk_application_new ("com.github.ToshioCP.tfv1", G_APPLICATION_FLAGS_NONE);
41 g_signal_connect (app, "activate", G_CALLBACK (app_activate), NULL);
42 stat = g_application_run (G_APPLICATION (app), argc, argv);
43 g_object_unref (app);
44 return stat;
45 }在程序第25行创建了一个 GtkTextView 实例，并用指针 tv 保存了该实例。当一个 GtkTextView 创建时，一个 GtkTextBuffer 也会被创建出来，并自动连接到 GtkTextView 上面。我们可以将 GtkTextBuffer 简称为 buffer。接着下一行代码使用指针 tb 保存了该 buffer，随后 10 ~ 20 行的文本被传给了该 buffer，现在该 buffer 中已经有了文本，我们可以在 GtkTextView 上显示或者编辑该文本。
GtkTextView 有一个换行模式，当它设置为 GTK_WRAP_WORD_CHAR 时，文本会在单词之间换行，如果单词的长度已经超过一行，也会在字母间换行。
第30行，tv 被附加到了 win 作为一个子控件。
编译运行：
可以看到窗口中有一个光标，您可以在 GtkTextView 上添加或删除任何字符，并且您的更改会被实时保存在 GtkTextBuffer 中。如果添加超出窗口限制的更多字符，则高度会增加并且窗口会扩展。如果高度大于显示屏的高度，您将没法再控制窗口的大小，这是程序中的一个 Bug。这可以通过在 GtkApplicationWindow 和 GtkTextView 之间添加一个 GtkScrolledWindow 来解决。
我们需要做的是：
- 创建一个 GtkScrolledWindow 并将其作为 GtkApplicationWindow 的子控件插入
- 将 GtkTextView 控件作为字控件插入 GtkScrolledWindow。
修改tfv1.c并保存为tfv2.c，这两个文件之间的差异很小：
$ cd tfv; diff tfv1.c tfv2.c
5a6
> GtkWidget *scr;
24a26,28
> scr = gtk_scrolled_window_new ();
> gtk_window_set_child (GTK_WINDOW (win), scr);
>
30c34
< gtk_window_set_child (GTK_WINDOW (win), tv);
---
> gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), tv);
40c44
< app = gtk_application_new ("com.github.ToshioCP.tfv1", G_APPLICATION_FLAGS_NONE);
---
> app = gtk_application_new ("com.github.ToshioCP.tfv2", G_APPLICATION_FLAGS_NONE);
下面是完整的 tfv2.c 程序：
1 #include <gtk/gtk.h>
2
3 static void
4 app_activate (GApplication *app, gpointer user_data) {
5 GtkWidget *win;
6 GtkWidget *scr;
7 GtkWidget *tv;
8 GtkTextBuffer *tb;
9 gchar *text;
10
11 text =
12 "Once upon a time, there was an old man who was called Taketori-no-Okina. "
13 "It is a japanese word that means a man whose work is making bamboo baskets.\n"
14 "One day, he went into a mountain and found a shining bamboo. "
15 "\"What a mysterious bamboo it is!,\" he said. "
16 "He cut it, then there was a small cute baby girl in it. "
17 "The girl was shining faintly. "
18 "He thought this baby girl is a gift from Heaven and took her home.\n"
19 "His wife was surprized at his tale. "
20 "They were very happy because they had no children. "
21 ;
22 win = gtk_application_window_new (GTK_APPLICATION (app));
23 gtk_window_set_title (GTK_WINDOW (win), "Taketori");
24 gtk_window_set_default_size (GTK_WINDOW (win), 400, 300);
25
26 scr = gtk_scrolled_window_new ();
27 gtk_window_set_child (GTK_WINDOW (win), scr);
28
29 tv = gtk_text_view_new ();
30 tb = gtk_text_view_get_buffer (GTK_TEXT_VIEW (tv));
31 gtk_text_buffer_set_text (tb, text, -1);
32 gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD_CHAR);
33
34 gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), tv);
35
36 gtk_widget_show (win);
37 }
38
39 int
40 main (int argc, char **argv) {
41 GtkApplication *app;
42 int stat;
43
44 app = gtk_application_new ("com.github.ToshioCP.tfv2", G_APPLICATION_FLAGS_NONE);
45 g_signal_connect (app, "activate", G_CALLBACK (app_activate), NULL);
46 stat = g_application_run (G_APPLICATION (app), argc, argv);
47 g_object_unref (app);
48 return stat;
49 }编译并运行，请注意，当您键入大量字符时，这次窗口不会扩展，它会滚动并显示一个滚动条。