如何在 gtk 中将小部件作为不同的线程加载?(瓦拉)

Question

我创建了这个类，出于效率原因，我想将缩略图作为不同的线程加载到iconview中，因为如果我在同一线程中执行此操作，gui 加载速度会非常慢。但是当我创建线程时，它不起作用，它会绘制一些缩略图，然后它们消失。当我使用加入时，它可以工作。这是我的代码：

    public class FotoThumbnailPane : Gtk.ScrolledWindow{
private FotoThumbnailPane_i pane;   
private string namet;
public FotoThumbnailPane(string name){
    this.namet = name;
}
public void set_imagelist(fileutils.ImageList image_list){
    pane = new FotoThumbnailPane_i(image_list);
    this.add (pane);
    this.set_min_content_width(140);
    this.show_all();
}
    //This is my threaded function
    public void* load_thumbs(){
    pane.set_visible(false);
    pane.newmodel = new Gtk.ListStore (2, typeof (Gdk.Pixbuf), typeof (string));
    pane.set_selection_mode (Gtk.SelectionMode.SINGLE);
    pane.set_pixbuf_column (0);
    pane.set_model(pane.newmodel);
    string icon_style = """
            .thumbnail-view {
                background-color: #FFFFFF;
            }
            .thumbnail-view:selected {
                background-color: #9D9D9D;
                border-color: shade (mix (rgb (34, 255, 120), #fff, 0.5), 0.9);
            }
        """;
    var icon_view_style = new Gtk.CssProvider ();
        try {
            icon_view_style.load_from_data (icon_style, -1);
        } catch (Error e) {
            warning (e.message);
        }
        pane.get_style_context ().add_class ("thumbnail-view");
    pane.get_style_context ().add_provider (icon_view_style, Gtk.STYLE_PROVIDER_PRIORITY_THEME);
    //Add thumbnails to the iconview
    string buff;
    for(int i=1; i<pane.image_list.size; i++){
    buff = pane.image_list.get_full_filename(i);
    stdout.printf("Added %s to thumbnailn", buff);
            var image = new Gdk.Pixbuf.from_file_at_scale(buff, 110, 80, false);
            // Add the wallpaper name and thumbnail to the IconView
            Gtk.TreeIter root;
            pane.newmodel.append(out root);
            pane.newmodel.set(root, 0, image, -1);
            pane.newmodel.set(root, 1, pane.image_list.get_filename(i), -1);
            // Select the thumbnail if it is the first in list
            if (i==0) {
                pane.select_path (pane.newmodel.get_path (root));
            }    
            pane.iters.append (root);
    }
    pane.set_sensitive(true);
    this.queue_draw();
return null;
}

}

Answer 1

您实际上不需要处理程序中的线程 - 您只需使用异步方法来加载内容即可。 具体来说，Gdk.Pixbuf.new_from_stream_at_scale_async。

下面是一个示例：

public async void load (Gtk.Image img, string filename) {
  GLib.File file = GLib.File.new_for_commandline_arg (filename);
  try {
    GLib.InputStream stream = yield file.read_async ();
    Gdk.Pixbuf pixbuf = yield Gdk.Pixbuf.new_from_stream_at_scale_async (stream, 320, -1, true);
    img.set_from_pixbuf (pixbuf);
  } catch ( GLib.Error e ) {
    GLib.error (e.message);
  }
}
private static int main (string[] args) {
  GLib.return_val_if_fail (args.length > 1, -1);
  Gtk.init (ref args);
  Gtk.Window win = new Gtk.Window ();
  win.destroy.connect (() => {
      Gtk.main_quit ();
    });
  Gtk.Image image = new Gtk.Image ();
  win.add (image);
  load.begin (image, args[1], (obj, async_res) => {
      GLib.debug ("Finished loading.");
    });
  win.show_all ();
  Gtk.main ();
  return 0;
}