An Introduction to C & GUI Programming -----Simon Long 学习笔记 3

这一讲讲的是按键button

#include 

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);
    GtkWidget *btn = gtk_button_new_with_label ("Close window");

    gtk_window_set_title (GTK_WINDOW(win1), "QT is better than GTK");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK is better than QT");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120);
    gtk_container_add (GTK_CONTAINER (win1), btn);
    gtk_widget_show (win2);
    gtk_widget_show_all (win1);
    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

  出现了一个新的函数 gtk_widget_show_all，把gtk_widget_show_all  (win1)改为gtk_widget_show(win1)看看会出现什么情况

#include 

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);
    GtkWidget *btn = gtk_button_new_with_label ("Close window");

    gtk_window_set_title (GTK_WINDOW(win1), "QT is better than GTK");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK is better than QT");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120  );
    gtk_container_add (GTK_CONTAINER (win1), btn);
    gtk_widget_show (win1);
    gtk_widget_show (win2);
    gtk_main ();
    return 0;
}

结果

 发现按键不见了，猜测 gtk_widget_show_all 会显示1个窗口中所有的内容，多加几个按键试试看

#include 

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);

    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 ("Close window3");

    gtk_window_set_title (GTK_WINDOW(win1), "QT is better than GTK");
    gtk_window_set_title (GTK_WINDOW(win2), "GTK is better than QT");
    gtk_window_set_default_size(GTK_WINDOW(win1), 120, 240);
    gtk_window_set_default_size(GTK_WINDOW(win2), 240, 120  );
    gtk_container_add (GTK_CONTAINER (win1), btn1);
    gtk_container_add (GTK_CONTAINER (win1), btn2);
    gtk_container_add (GTK_CONTAINER (win2), btn3);
    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

结果

 编译告警但是能运行，告警窗口win1 有1个widget，再加一个不行，也不知道为啥，先归类到待处理类别中。(可以用box解决这个问题，见学习笔记4)

按键button的信号回调函数

#include 
// 点击按键的时候会触发调用这个函数
void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye\n");
    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);

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

    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  );

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (btn2, "clicked", G_CALLBACK (end_program), NULL);
    gtk_container_add (GTK_CONTAINER (win1), btn1);
    gtk_container_add (GTK_CONTAINER (win2), btn2);
    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

结果 ： 无论点击窗口1还是2的close window，均会关闭2个窗口，并在shell下打印bye bye。

 点击窗口的x可以关闭程序（

if we click the X at the top right, the window closes but the
program doesn’t exit. Let’s fix that.
The way we do this is to connect another handler to the signal generated when that X is
clicked. The name of this signal is delete_event , and it is generated from the window
widget）

#include 
void end_program (GtkWidget *wid, gpointer ptr)
{
    printf("bybye\n");
    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);

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

    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  );

    g_signal_connect (btn1, "clicked", G_CALLBACK (end_program), NULL);
    g_signal_connect (win2, "delete_event", G_CALLBACK (end_program), NULL);  // 窗口点击X会触发delete_event信号
    gtk_container_add (GTK_CONTAINER (win1), btn1);
    gtk_container_add (GTK_CONTAINER (win2), btn2);
    gtk_widget_show_all (win1);
    gtk_widget_show_all (win2);
    gtk_main ();
    return 0;
}

结果：点击 Close window2没反应了，点击X关闭所有窗口了