An Introduction to C & GUI Programming -----Simon Long 学习笔记 4

Labels and layout  标签和布局

Label---主要用于显示文字，用户不能修改文字

demo

#include <gtk/gtk.h>
void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye
");
    gtk_main_quit ();
}

int main (int argc, char *argv[])
{
    gtk_init (&argc, &argv);

    GtkWidget *win1 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    GtkWidget *win2 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW(win1), "QT");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120);

    GtkWidget *btn1 = gtk_button_new_with_label ("Close window1");
    GtkWidget *btn2 = gtk_button_new_with_label ("Close window2");

    GtkWidget *labelA = gtk_label_new ("LABELA");
    GtkWidget *labelB = gtk_label_new ("LABELB");
    gtk_container_add (GTK_CONTAINER (win1), labelA);
    gtk_container_add (GTK_CONTAINER (win2), labelB);

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (win2, "delete_event", G_CALLBACK (end_program), NULL);

    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

编译  gcc `pkg-config --cflags gtk+-3.0` test.c -o hello `pkg-config --libs gtk+-3.0`

结果

作者在这里也说明了为什么1个window只能有1个widget 

a GtkWindow can only contain one widget at a time, and that this one already contains a GtkButton. 

So you can only put one widget into a window, but we want to have two – a button and a label; that’s not going to work

解决方法---BOX

#include <gtk/gtk.h>

void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye
");
    gtk_main_quit ();
}

int main (int argc, char *argv[])
{
    gtk_init (&argc, &argv);

    GtkWidget *win1 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    GtkWidget *win2 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW(win1), "QT");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120);

    GtkWidget *btn1 = gtk_button_new_with_label ("Close window1");
    GtkWidget *btn2 = gtk_button_new_with_label ("Close window2");

    GtkWidget *labelA = gtk_label_new ("LABELA");
    GtkWidget *labelB = gtk_label_new ("LABELB");
    gtk_label_set_text(GTK_LABEL(labelA), "LABELAAAAAA");
    gtk_label_set_text(GTK_LABEL(labelB), "LABELBBBBBB");
    GtkWidget *box1 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 5);
    GtkWidget *box2 = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5);

    gtk_box_pack_start (GTK_BOX (box1), btn1, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box1), labelA, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), btn2, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), labelB, TRUE, TRUE, 0);

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (win2, "delete_event", G_CALLBACK (end_program), NULL);

    gtk_container_add (GTK_CONTAINER (win1), box1);
    gtk_container_add (GTK_CONTAINER (win2), box2);

    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

结果

 2个新函数，gtk_box_new，gtk_box_pack_start函数细节见 https://developer.gnome.org/gtk3/stable/GtkBox.html

 点击按键，显示按键点击次数

#include <gtk/gtk.h>

void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye
");
    gtk_main_quit ();
}

void count (GtkWidget *wid, gpointer ptr)
{
    char buffer[30] = { 0 };
    static int count = 0;
    count++;
    sprintf (buffer, "Button pressed %d times", count);
    gtk_label_set_text (GTK_LABEL (ptr), buffer);
}

int main (int argc, char *argv[])
{
    gtk_init (&argc, &argv);

    GtkWidget *win1 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    GtkWidget *win2 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW(win1), "QT");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120);

    GtkWidget *btn1 = gtk_button_new_with_label ("Close window1");
    GtkWidget *btn2 = gtk_button_new_with_label ("Close window2");
    GtkWidget *btn3 = gtk_button_new_with_label ("count
");

    GtkWidget *labelA = gtk_label_new ("LABELA");
    GtkWidget *labelB = gtk_label_new ("LABELB");
    gtk_label_set_text(GTK_LABEL(labelA), "LABELAAAAAA");
    gtk_label_set_text(GTK_LABEL(labelB), "LABELBBBBBB");
    GtkWidget *box1 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 5);
    GtkWidget *box2 = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5);

    gtk_box_pack_start (GTK_BOX (box1), btn1, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box1), labelA, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box1), btn3, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), btn2, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), labelB, TRUE, TRUE, 0);

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (btn3, "clicked", G_CALLBACK (count), labelB);
    g_signal_connect (win2, "delete_event", G_CALLBACK (end_program), NULL);

    gtk_container_add (GTK_CONTAINER (win1), box1);
    gtk_container_add (GTK_CONTAINER (win2), box2);

    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

结果

启动时

 点击count 按钮时

 点击count时，绑定多个label会如何呢

#include <gtk/gtk.h>

void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye
");
    gtk_main_quit ();
}

void count (GtkWidget *wid, gpointer ptr)
{
    char buffer[30] = { 0 };
    static int count= 0;
    count++;
    sprintf (buffer, "Button pressed %d times", count);
    gtk_label_set_text (GTK_LABEL (ptr), buffer);
}

int main (int argc, char *argv[])
{
    gtk_init (&argc, &argv);

    GtkWidget *win1 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    GtkWidget *win2 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW(win1), "QT");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120);

    GtkWidget *btn1 = gtk_button_new_with_label ("Close window1");
    GtkWidget *btn2 = gtk_button_new_with_label ("Close window2");
    GtkWidget *btn3 = gtk_button_new_with_label ("count
");

    GtkWidget *labelA = gtk_label_new ("LABELA");
    GtkWidget *labelB = gtk_label_new ("LABELB");
    gtk_label_set_text(GTK_LABEL(labelA), "LABELAAAAAA");
    gtk_label_set_text(GTK_LABEL(labelB), "LABELBBBBBB");
    GtkWidget *box1 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 5);
    GtkWidget *box2 = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5);

    gtk_box_pack_start (GTK_BOX (box1), btn1, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box1), labelA, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box1), btn3, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), btn2, TRUE, TRUE, 0);
    gtk_box_pack_start (GTK_BOX (box2), labelB, TRUE, TRUE, 0);

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (btn3, "clicked", G_CALLBACK (count), labelB);
    g_signal_connect (btn3, "clicked", G_CALLBACK (count), labelA);
    g_signal_connect (win2, "delete_event", G_CALLBACK (end_program), NULL);

    gtk_container_add (GTK_CONTAINER (win1), box1);
    gtk_container_add (GTK_CONTAINER (win2), box2);

    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

 结果，实际点击1次但显示2次，又碰到麻烦了，先归入待处理分类。