Linux 下从头再走 GTK+-3.0 (五)

<?xml version="1.0" encoding="UTF-8"?>
<interface>
    <object id="window" class="GtkWindow">
        <property name="visible">True</property>
        <property name="title">GtkBuilder</property>
        <property name="border-width">30</property>
        <child>
            <object id="grid" class="GtkGrid">
                <property name="visible">True</property>
                <child>
                    <object id="print_hello" class="GtkButton">
                        <property name="visible">True</property>
                        <property name="label">Button 1</property>
                    </object>
                    <packing>
                        <property name="left-attach">0</property>
                        <property name="top-attach">0</property>
                    </packing>
                </child>
                <child>
                    <object id="print_entry" class="GtkButton">
                        <property name="visible">True</property>
                        <property name="label">Button 2</property>
                    </object>
                    <packing>
                        <property name="left-attach">1</property>
                        <property name="top-attach">0</property>
                    </packing>
                </child>
                <child>
                    <object id="entry" class="GtkEntry">
                        <property name="visible">True</property>
                    </object>
                    <packing>
                        <property name="left-attach">0</property>
                        <property name="top-attach">1</property>
                        <property name="width">2</property>
                    </packing>
                </child>
            </object>
            <packing>
            </packing>
        </child>
    </object>
</interface>

#include <gtk/gtk.h>

static void print_hello(GtkWidget *button , gpointer data);
static void activate(GtkApplication *app , gpointer data);
static void print_entry(GtkWidget * button , gpointer entry);

int main(int argc , char **argv)
{
    GtkApplication *app;
    int app_status;

    app = gtk_application_new("org.rain.example" , G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app , "activate" , G_CALLBACK(activate) , NULL);
    app_status = g_application_run(G_APPLICATION(app) , argc , argv);

    g_object_unref(app);
    return app_status;
}

static void print_hello(GtkWidget *button , gpointer data)
{
    printf("Hello,world!\n");
}

static void print_entry(GtkWidget * button , gpointer entry)
{
    const gchar *entry_buf;
    //获取输入框的内容，返回一个 const gchar 指针 , gchar 即是 char
    entry_buf = gtk_entry_get_text( GTK_ENTRY(entry) );
    if('\0' != entry_buf[0])
        printf("%s\n" , entry_buf);
}

static void activate(GtkApplication *app , gpointer data)
{
    GtkBuilder *builder;
    GObject *window;
    GObject *button;
    GObject *entry;

    //创建一个 GtkBuilder 。
    builder = gtk_builder_new();
    //将描述 UI 的文件添加到 Builder 中。
    gtk_builder_add_from_file(builder , "example.ui" , NULL);

    //可以用该函数获取 Builder 创建的对象，根据 example.ui 文件中设置的 object 的 id 来获取。
    window = gtk_builder_get_object(builder , "window");
    gtk_application_add_window(app , GTK_WINDOW(window));

    //注意该函数返回的是一个指向 GObject 对象的指针。
    button = gtk_builder_get_object(builder , "print_hello");
    //设置按钮标签
    gtk_button_set_label ( GTK_BUTTON (button) , "PrintHello");
    g_signal_connect(button , "clicked" , G_CALLBACK(print_hello) , NULL);

    //获取输入框对象。
    entry  = gtk_builder_get_object(builder , "entry");
    
    button = gtk_builder_get_object(builder , "print_entry");
    gtk_button_set_label ( GTK_BUTTON (button) , "PrintEntry");
    //调用 print_entry 时传递用户参数 entry 。
    g_signal_connect(button , "clicked" , G_CALLBACK(print_entry) , entry);
    
}

gcc example.c `pkg-config --cflags --libs gtk+-3.0`
./a.out