c - 在 GTK+3 中，我如何获得绘图区域来响应鼠标事件？

Question

在 GTK+3 中，我如何获得一个 drawing_area 来响应鼠标事件？

在 main() 函数中，我声明了我的drawing_area:

GtkWidget *drawing_area;

然后我将 drawing_area 与鼠标点击信号连接起来:

g_signal_connect(drawing_area, "button-press-event", G_CALLBACK(clicked), NULL);

函数“clicked”定义为:

static gboolean clicked(GtkWidget *widget, GdkEventButton *event, gpointer user_data)

    printf("Clicked! \n");

    return TRUE;
}

程序运行并显示 drawing_area 但是当我点击它时，没有任何反应，没有任何反应!为什么会这样？

Answer 1

GtkDrawingArea 好像默认接收不到鼠标事件

查看 documentation :

To receive mouse events on a drawing area, you will need to enable them with gtk_widget_add_events(). To receive keyboard events, you will need to set the “can-focus” property on the drawing area, and you should probably draw some user-visible indication that the drawing area is focused. Use gtk_widget_has_focus() in your expose event handler to decide whether to draw the focus indicator. See gtk_render_focus() for one way to draw focus.

或者尝试将事件 "button-press-event" 连接到窗口:

g_signal_connect(window, "button-press-event", G_CALLBACK(clicked), NULL);

代替

g_signal_connect(drawing_area, "button-press-event", G_CALLBACK(clicked), NULL);

如本例所示:

http://zetcode.com/gfx/cairo/basicdrawing/