click - Vala 图片点击事件。如何获得点击的协调？

Question

我尝试捕捉点击的协调。我创建了 Gtk.Window、EventBox 并将图像放入其中，将一些 EventButton 连接到 button_press_event 并通过某种方法连接到该信号。此方法尝试从 EventButton 对象获取 x 和 y，但它们始终为 0。源代码如下:

using Gtk;
public class ComixTranslator : Window 
{
private Gtk.Image CurPage;
private Gdk.Pixbuf Canvas;
private Gtk.EventBox eventbox1;
private Gdk.EventButton ebutton1;

public bool FillDot() {
    GLib.message("pressed in %g,%g",ebutton1.x,ebutton1.y);
    return true;
}

public ComixTranslator () {
    this.title = "Image Click Sample";
    this.window_position = Gtk.WindowPosition.CENTER;
    this.destroy.connect(Gtk.main_quit);
    this.set_default_size(800,600);

    this.CurPage = new Gtk.Image();
    this.CurPage.set_from_file("test.jpg");
    this.Canvas = CurPage.pixbuf;

    this.eventbox1 = new Gtk.EventBox();
    this.eventbox1.button_press_event(ebutton1);
    this.eventbox1.button_press_event.connect(FillDot);
    this.eventbox1.add(CurPage);

    this.add(eventbox1);
}

public static int main(string[] args) {
    Gtk.init(ref args);

    ComixTranslator MainWindow = new ComixTranslator();
    MainWindow.show_all();
    Gtk.main();
    return 0;
}
}

Answer 1

您似乎对信号的工作原理感到困惑——您可能需要考虑阅读 that part of the Vala Tutorial .这是更正后的版本:

using Gtk;
public class ComixTranslator : Window 
{
  private Gtk.Image CurPage;
  private Gdk.Pixbuf Canvas;
  private Gtk.EventBox eventbox1;

  public bool FillDot(Gtk.Widget sender, Gdk.EventButton evt) {
    GLib.message("pressed in %g,%g",evt.x,evt.y);
    return true;
  }

  public ComixTranslator () {
    this.title = "Image Click Sample";
    this.window_position = Gtk.WindowPosition.CENTER;
    this.destroy.connect(Gtk.main_quit);
    this.set_default_size(800,600);

    this.CurPage = new Gtk.Image();
    this.CurPage.set_from_file("test.jpg");
    this.Canvas = CurPage.pixbuf;

    this.eventbox1 = new Gtk.EventBox();
    this.eventbox1.button_press_event.connect(FillDot);
    this.eventbox1.add(CurPage);

    this.add(eventbox1);
  }

  public static int main(string[] args) {
    Gtk.init(ref args);

    ComixTranslator MainWindow = new ComixTranslator();
    MainWindow.show_all();
    Gtk.main();
    return 0;
  }
}

注意回调接受 Gdk.EventButton 作为参数。在您的代码中，您有 this.eventbox1.button_press_event(ebutton1);，它将发出 button_press_event 信号并将来自 ebutton1 的数据作为其参数。