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c - 使用 GtkFileChooserButton 和 GtkFileChooserDialog 的区别

问题描述

我想让用户选择两个目录，然后在单击按钮后检索他们的 URI，这样我就可以将它们传递给另一个函数。现在我试图做一些事情：

directory1 = gtk_file_chooser_button_new ("Choose directory 1",GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER);

目录 2 也是如此。然后将它们放入结构中

struct directories {
    GtkWidget *first;
    GtkWidget *second;
};

struct directories directory;
    directory.first = directory1;
    directory.second = directory2;

单击按钮后，将其传递给当前什么都不做但尝试检索 URI 并打印它们的函数。

g_signal_connect(button, "clicked", G_CALLBACK(print_test), &directory);

print_test (struct directories *dirc)
{
    g_print("%s\n", gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(dirc->first)));
    g_print("%s\n", gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(dirc->second)));
}

我也尝试过替换GTK_FILE_CHOOSER，GTK_FILE_CHOOSER_BUTTON但结果是一样的：我的程序已编译，我选择了一些目录，在激活按钮后它崩溃并打印了一个

（无效的）

以及以下调试信息

GLib-GObject-WARNING **: 02:52:03.786: invalid uninstantiatable type 'gchararray' in cast to 'GtkFileChooserButton'
Gtk-CRITICAL **: 02:52:03.786: gtk_file_chooser_get_uri: assertion 'GTK_IS_FILE_CHOOSER (chooser)' failed

我认为 gtk_file_chooser_button 是一个很好的解决方案，因为它似乎比手动建立对话框更简单，但现在我开始质疑是否允许我以这种方式使用它，或者我的程序失败是错误的传递指针方法的错误打印测试。不幸的是，我发现的所有示例都集中在使用对话框上，所以我没有找到一个可以学习如何使用 gtk_file_chooser_button 的好示例。

编辑：根据要求，我展示我的代码示例。我只删除了与此问题无关的其他类型的按钮，并执行了第一条评论中描述的更改，因此与上述问题相比，您可以观察到两行的细微差别。

#include <stdio.h>
#include <gtk/gtk.h>

struct directories {
    GtkWidget *first;
    GtkWidget *second;
};

static void
print_test (GtkWidget *somewidget, struct directories *dirc)
{
    g_print("%s\n", gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(dirc->first)));
    g_print("%s\n", gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(dirc->second)));
}

static void
set_expand (GtkWidget *widget)
{
    gtk_widget_set_hexpand(widget, 1);
    gtk_widget_set_vexpand(widget, 1);
}

static void
activate (GtkApplication* app,
          gpointer        user_data)
{
    GtkWidget *window;
    GtkWidget *grid;
    GtkWidget *frame;
    GtkWidget *settings;
    GtkWidget *directory1;
    GtkWidget *directory2;
    GtkWidget *button;

    //Prepare the window
    window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "Sagger");
    gtk_window_set_default_size (GTK_WINDOW (window), 400, 200);
    gtk_window_set_position(GTK_WINDOW(window),GTK_WIN_POS_CENTER);

    //Prepare the grid
    grid = gtk_grid_new();
    //gtk_grid_set_column_homogeneous(grid, 1);
    //gtk_widget_set_halign (grid, GTK_ALIGN_FILL);
    //gtk_widget_set_valign (grid, GTK_ALIGN_FILL);
    set_expand(grid);
    gtk_container_add(GTK_CONTAINER(window), grid);

    //Prepare directory chooser
    settings = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
    frame = gtk_frame_new("Choose directories");
    set_expand(settings);
    gtk_container_add(GTK_CONTAINER(frame), settings);
    directory1 = gtk_file_chooser_button_new ("Source directory",GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER);
    set_expand(directory1);
    gtk_container_add(GTK_CONTAINER(settings), directory1);
    directory2 = gtk_file_chooser_button_new ("Target directory",GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER);
    set_expand(directory2);
    gtk_container_add(GTK_CONTAINER(settings), directory2);
    gtk_grid_attach(grid, frame, 0, 0, 2, 1);

    //Prepare the run button
    settings = gtk_button_box_new(GTK_ORIENTATION_HORIZONTAL);
    gtk_button_box_set_layout(GTK_BUTTON_BOX(settings), GTK_BUTTONBOX_EXPAND);
    set_expand(settings);
    gtk_grid_attach(grid, settings, 0, 2, 2, 1);
    button = gtk_button_new_with_label("RUN");

    //Try to pass the chosen directories
    struct directories directory;
    directory.first = directory1;
    directory.second = directory2;
    g_signal_connect(G_OBJECT(button), "clicked", G_CALLBACK(print_test), (gpointer) &directory);

    gtk_container_add(GTK_CONTAINER(settings), button);

    gtk_widget_show_all (window);
}

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

    app = gtk_application_new ("pl.etua.sagger", G_APPLICATION_FLAGS_NONE);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);

    return status;
}

标签： cgtkgtk3

解决方案

directory是函数的本地activate()函数，并且如评论中所述，当它超出范围时将被销毁。稍后，当print_test()单击按钮时调用该函数时，它会尝试访问该内存，从而导致分段错误。

两个简单的方法：

使directory全局：

struct directories {
    GtkWidget *first;
    GtkWidget *second;
};
struct directories directory;

或使其成为静态activate()：

static struct directories directory;

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