KJAVA虚拟机Hack笔记-用GTK+实现Form


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文章出处：http://www.limodev.cn/blog
作者联系方式：李先静 <xianjimli at hotmail dot com>

KJAVA虚拟机Hack笔记-用GTK+实现Form

Form是一个窗口，在上面可以放控件和命令。Form上可以放很多个控件，一个屏幕可能显示不下，所以在适当的时候需要滚动条，而且只能出现垂直滚动条。为了实现垂直滚动功能，我们先在窗口上放一个滚动窗口：

form = gtk_window_new (GTK_WINDOW_TOPLEVEL);
scrolledwindow = gtk_scrolled_window_new (NULL, NULL);
gtk_widget_show (scrolledwindow);
gtk_container_add (GTK_CONTAINER (form), scrolledwindow);
gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolledwindow), GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC);
viewport = gtk_viewport_new (NULL, NULL);
gtk_widget_show (viewport);
gtk_container_add (GTK_CONTAINER (scrolledwindow), viewport);

用vbox来负责控件的排版：

container = gtk_vbox_new (FALSE, 3);
gtk_widget_show (container);
gtk_container_add (GTK_CONTAINER (viewport), container);

命令用菜单来实现：

menubar = gtk_menu_bar_new ();
gtk_widget_show (menubar);
gtk_box_pack_start (GTK_BOX (container), menubar, FALSE, FALSE, 0);

lfpport_form_create的实现如下：

MidpError lfpport_form_create(MidpDisplayable* dispPtr,
                  const pcsl_string* title, const pcsl_string* tickerText)
{
    GtkWidget* widget = create_form();
    dispPtr->frame.widgetPtr      = widget;
    dispPtr->frame.show           = gtk_frame_show;
    dispPtr->frame.hideAndDelete  = gtk_frame_hide_and_delete;
    dispPtr->frame.handleEvent    = form_handle_event;
    dispPtr->setTitle             = displayable_set_title;
    dispPtr->setTicker            = displayable_set_ticker;
 
    dispPtr->setTitle(dispPtr, title);
    displayable_set_ticker(dispPtr, tickerText);
 
    frame_hook_delete_event(widget);
 
    lfpport_set_active_screen(dispPtr->frame.widgetPtr);
 
    return KNI_OK;
}

里面几个虚函数很容易实现，其中实现gtk_frame_hide_and_delete时需要点技巧，因为在切换当前窗口时，MIDP先隐藏再显示，所以在切换的过程会闪一下背景窗口，为了避免这种情况，我们可以在idle里再销毁窗口。

lfpport_form_set_content_size设置viewpoint的大小：
MidpError lfpport_form_set_content_size(MidpDisplayable* dispPtr,
                    int w, int h)
{
    GtkWidget* widget = GTK_WIDGET(dispPtr->frame.widgetPtr);
    GtkWidget* viewport = lookup_widget(widget, "viewport");
 
    gtk_widget_set_size_request(viewport, w, h);
 
    return KNI_OK;
}

lfpport_form_set_current_item设置当前的焦点：

MidpError lfpport_form_set_current_item(MidpItem* itemPtr, int yOffset)
{
    GtkWidget* widget = GTK_WIDGET(itemPtr->widgetPtr);
    GtkWidget* item_widget = g_object_get_data(G_OBJECT(widget), "item_widget");
 
    gtk_widget_grab_focus(item_widget);
 
    (void)yOffset;
 
    return KNI_OK;
}

lfpport_form_get_scroll_position得到当前窗口的滚动条的位置：

MidpError lfpport_form_get_scroll_position(int *pos)
{
    GtkWidget* form = lfpport_get_active_screen();
    GtkWidget* swindow = form != NULL ? lookup_widget(form, "scrolledwindow"):NULL;
 
    if(swindow != NULL)
    {
        *pos = gtk_adjustment_get_value(gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WI
NDOW(swindow)));
    }
 
    return KNI_OK;
}

lfpport_form_set_scroll_position设置滚动条的位置：

MidpError lfpport_form_set_scroll_position(int pos)
{
    GtkWidget* form = lfpport_get_active_screen();
    GtkWidget* swindow = form != NULL ? lookup_widget(form, "scrolledwindow"):NULL;
 
    if(swindow != NULL)
    {
        gtk_adjustment_set_value(gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(sw
indow)), pos);
    }
 
    return KNI_OK;
}

lfpport_form_get_viewport_height得到viewpoint的高度：

MidpError lfpport_form_get_viewport_height(int *height)
{
    GtkWidget* form = lfpport_get_active_screen();
    GtkWidget* viewport = form != NULL ? lookup_widget(form, "viewport") : NULL;
 
    if(viewport != NULL)
    {
        *height = viewport->allocation.height;
    }
 
    return KNI_OK;
}

Category: KVM hack notes