gtkfilechooser.sgml

linux下电话本所依赖的一些图形库

<!-- ##### SECTION Title ##### -->
GtkFileChooser

<!-- ##### SECTION Short_Description ##### -->
File chooser interface used by GtkFileChooserWidget and GtkFileChooserDialog

<!-- ##### SECTION Long_Description ##### -->
    <para>
      #GtkFileChooser is an interface that can be implemented by file
      selection widgets.  In GTK+, the main objects that implement this
      interface are #GtkFileChooserWidget, #GtkFileChooserDialog, and
      #GtkFileChooserButton.  You do not need to write an object that
      implements the #GtkFileChooser interface unless you are trying to
      adapt an existing file selector to expose a standard programming
      interface.
    </para>

    <refsect2 id="gtkfilechooser-encodings">
      <title>File Names and Encodings</title>

      <para>
	When the user is finished selecting files in a
	#GtkFileChooser, your program can get the selected names
	either as filenames or as URIs.  For URIs, the normal escaping
	rules are applied if the URI contains non-ASCII characters.
	However, filenames are <emphasis>always</emphasis> returned in
	the character set specified by the
	<envar>G_FILENAME_ENCODING</envar> environment variable.
	Please see the Glib documentation for more details about this
	variable.
      </para>

      <important>
	<para>
	  This means that while you can pass the result of
	  gtk_file_chooser_get_filename() to
	  <function>open(2)</function> or
	  <function>fopen(3)</function>, you may not be able to
	  directly set it as the text of a #GtkLabel widget unless you
	  convert it first to UTF-8, which all GTK+ widgets expect.
	  You should use g_filename_to_utf8() to convert filenames
	  into strings that can be passed to GTK+ widgets.
	</para>
      </important>
    </refsect2>

    <refsect2 id="gtkfilechooser-preview">
      <title>Adding a Preview Widget</title>

      <para>
	You can add a custom preview widget to a file chooser and then
	get notification about when the preview needs to be updated.
	To install a preview widget, use
	gtk_file_chooser_set_preview_widget().  Then, connect to the
	#GtkFileChooser::update-preview signal to get notified when
	you need to update the contents of the preview.
      </para>

      <para>
	Your callback should use
	gtk_file_chooser_get_preview_filename() to see what needs
	previewing.  Once you have generated the preview for the
	corresponding file, you must call
	gtk_file_chooser_set_preview_widget_active() with a boolean
	flag that indicates whether your callback could successfully
	generate a preview.
      </para>

      <example id="example-gtkfilechooser-preview">
	<title>Sample Usage</title>

	<programlisting>
{
  GtkImage *preview;

  ...

  preview = gtk_image_new (<!-- -->);

  gtk_file_chooser_set_preview_widget (my_file_chooser, preview);
  g_signal_connect (my_file_chooser, "update-preview",
		    G_CALLBACK (update_preview_cb), preview);
}

static void
update_preview_cb (GtkFileChooser *file_chooser, gpointer data)
{
  GtkWidget *preview;
  char *filename;
  GdkPixbuf *pixbuf;
  gboolean have_preview;

  preview = GTK_WIDGET (data);
  filename = gtk_file_chooser_get_preview_filename (file_chooser);

  pixbuf = gdk_pixbuf_new_from_file_at_size (filename, 128, 128, NULL);
  have_preview = (pixbuf != NULL);
  g_free (filename);

  gtk_image_set_from_pixbuf (GTK_IMAGE (preview), pixbuf);
  if (pixbuf)
    gdk_pixbuf_unref (pixbuf);

  gtk_file_chooser_set_preview_widget_active (file_chooser, have_preview);
}
	</programlisting>
      </example>
    </refsect2>

    <refsect2 id="gtkfilechooser-extra">
      <title>Adding Extra Widgets</title>

      <para>
	You can add extra widgets to a file chooser to provide options
	that are not present in the default design.  For example, you
	can add a toggle button to give the user the option to open a
	file in read-only mode.  You can use
	gtk_file_chooser_set_extra_widget() to insert additional
	widgets in a file chooser.
      </para>

      <example id="example-gtkfilechooser-extra">
	<title>Sample Usage</title>

	<programlisting>
{
  GtkWidget *toggle;

  ...

  toggle = gtk_check_button_new_with_label ("Open file read-only");
  gtk_widget_show (toggle);
  gtk_file_chooser_set_extra_widget (my_file_chooser, toggle);
}
	</programlisting>
      </example>

      <note>
	<para>
	  If you want to set more than one extra widget in the file
	  chooser, you can a container such as a GtkVBox or a GtkTable
	  and include your widgets in it.  Then, set the container as
	  the whole extra widget.
	</para>
      </note>
    </refsect2>

    <refsect2 id="gtkfilechooser-key-bindings">
      <title>Key Bindings</title>

      <para>
	Internally, GTK+ implements a file chooser's graphical user
	interface with the private
	<classname>GtkFileChooserDefaultClass</classname>.  This
	widget has several <link linkend="gtk-Bindings">key
	bindings</link> and their associated signals.  This section
	describes the available key binding signals.
      </para>

      <example id="gtkfilechooser-key-binding-example">
	<title>GtkFileChooser key binding example</title>

	<para>
	  The default keys that activate the key-binding signals in
	  <classname>GtkFileChooserDefaultClass</classname> are as
	  follows:
	</para>

	<informaltable>
	  <tgroup cols="2">
	    <tbody>
	      <row>
		<entry>Signal name</entry>
		<entry>Key</entry>
	      </row>
	      <row>
		<entry>location-popup</entry>
		<entry><keycombo><keycap>Control</keycap><keycap>L</keycap></keycombo></entry>
	      </row>
	      <row>
		<entry>up-folder</entry>
		<entry><keycombo><keycap>Alt</keycap><keycap>Up</keycap></keycombo></entry>
	      </row>
	      <row>
		<entry>down-folder</entry>
		<entry><keycombo><keycap>Alt</keycap><keycap>Down</keycap></keycombo></entry>
	      </row>
	      <row>
		<entry>home-folder</entry>
		<entry><keycombo><keycap>Alt</keycap><keycap>Home</keycap></keycombo></entry>
	      </row>
	    </tbody>
	  </tgroup>
	</informaltable>

	<para>
	  To change these defaults to something else, you could
	  include the following fragment in your
	  <filename>.gtkrc-2.0</filename> file:
	</para>

	<programlisting>
binding "my-own-gtkfilechooser-bindings" {
	bind "&lt;Alt&gt;&lt;Shift&gt;l" {
		"location-popup" ()
	}
	bind "&lt;Alt&gt;&lt;Shift&gt;Up" {
		"up-folder" ()
	}
	bind "&lt;Alt&gt;&lt;Shift&gt;Down" {
		"down-folder" ()
	}
	bind "&lt;Alt&gt;&lt;Shift&gt;Home" {
		"home-folder-folder" ()
	}
}

class "GtkFileChooserDefault" binding "my-own-gtkfilechooser-bindings"
	</programlisting>
      </example>

      <refsect3 id="GtkFileChooserDefault-location-popup">
	<title>The &quot;GtkFileChooserDefault::location-popup&quot; signal</title>

	<programlisting>
          void user_function (GtkFileChooserDefault *chooser,
                              <link linkend="gpointer">gpointer</link> user_data);
	</programlisting>

	<para>
	  This is used to make the file chooser show a "Location"
	  dialog which the user can use to manually type the name of
	  the file he wishes to select.  By default this is bound to
	  <keycombo><keycap>Control</keycap><keycap>L</keycap></keycombo>.
	</para>

	<variablelist role="params">
	  <varlistentry>
	    <term><parameter>chooser</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		the object which received the signal.
	      </simpara>
	    </listitem>
	  </varlistentry>
	  <varlistentry>
	    <term><parameter>user_data</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		user data set when the signal handler was connected.
	      </simpara>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </refsect3>

      <refsect3 id="GtkFileChooserDefault-up-folder">
	<title>The &quot;GtkFileChooserDefault::up-folder&quot; signal</title>

	<programlisting>
          void user_function (GtkFileChooserDefault *chooser,
                              <link linkend="gpointer">gpointer</link> user_data);
	</programlisting>

	<para>
	  This is used to make the file chooser go to the parent of
	  the current folder in the file hierarchy.  By default this
	  is bound to
	  <keycombo><keycap>Alt</keycap><keycap>Up</keycap></keycombo>.
	</para>

	<variablelist role="params">
	  <varlistentry>
	    <term><parameter>chooser</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		the object which received the signal.
	      </simpara>
	    </listitem>
	  </varlistentry>
	  <varlistentry>
	    <term><parameter>user_data</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		user data set when the signal handler was connected.
	      </simpara>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </refsect3>

      <refsect3 id="GtkFileChooserDefault-down-folder">
	<title>The &quot;GtkFileChooserDefault::down-folder&quot; signal</title>

	<programlisting>
          void user_function (GtkFileChooserDefault *chooser,
                              <link linkend="gpointer">gpointer</link> user_data);
	</programlisting>

	<para>
	  This is used to make the file chooser go to a child of the
	  current folder in the file hierarchy.  The subfolder that
	  will be used is displayed in the path bar widget of the file
	  chooser.  For example, if the path bar is showing
	  "/foo/<emphasis>bar/</emphasis>baz", then this will cause
	  the file chooser to switch to the "baz" subfolder.  By
	  default this is bound to
	  <keycombo><keycap>Alt</keycap><keycap>Down</keycap></keycombo>.
	</para>

	<variablelist role="params">
	  <varlistentry>
	    <term><parameter>chooser</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		the object which received the signal.
	      </simpara>
	    </listitem>
	  </varlistentry>
	  <varlistentry>
	    <term><parameter>user_data</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		user data set when the signal handler was connected.
	      </simpara>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </refsect3>

      <refsect3 id="GtkFileChooserDefault-home-folder">
	<title>The &quot;GtkFileChooserDefault::home-folder&quot; signal</title>

	<programlisting>
          void user_function (GtkFileChooserDefault *chooser,
                              <link linkend="gpointer">gpointer</link> user_data);
	</programlisting>

	<para>
	  This is used to make the file chooser show the user's home
	  folder in the file list.  By default this is bound to
	  <keycombo><keycap>Alt</keycap><keycap>Home</keycap></keycombo>.
	</para>

	<variablelist role="params">
	  <varlistentry>
	    <term><parameter>chooser</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		the object which received the signal.
	      </simpara>
	    </listitem>
	  </varlistentry>
	  <varlistentry>
	    <term><parameter>user_data</parameter>&nbsp;:</term>
	    <listitem>
	      <simpara>
		user data set when the signal handler was connected.
	      </simpara>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </refsect3>
    </refsect2>

<!-- ##### SECTION See_Also ##### -->
    <para>
      #GtkFileChooserDialog, #GtkFileChooserWidget, #GtkFileChooserButton
    </para>

<!-- ##### SECTION Stability_Level ##### -->


<!-- ##### STRUCT GtkFileChooser ##### -->
<para>

</para>


<!-- ##### SIGNAL GtkFileChooser::current-folder-changed ##### -->
<para>

</para>

@filechooser: the object which received the signal.

<!-- ##### SIGNAL GtkFileChooser::file-activated ##### -->
<para>

</para>

@filechooser: the object which received the signal.

<!-- ##### SIGNAL GtkFileChooser::selection-changed ##### -->
<para>

</para>

@filechooser: the object which received the signal.

<!-- ##### SIGNAL GtkFileChooser::update-preview ##### -->
<para>

</para>

@filechooser: the object which received the signal.

<!-- ##### ARG GtkFileChooser:action ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:extra-widget ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:file-system-backend ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:filter ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:local-only ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:preview-widget ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:preview-widget-active ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:select-multiple ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:show-hidden ##### -->
<para>

</para>

<!-- ##### ARG GtkFileChooser:use-preview-label ##### -->
<para>

</para>

<!-- ##### ENUM GtkFileChooserAction ##### -->
    <para>
      Describes whether a #GtkFileChooser is being used to open
      existing files or to save to a possibly new file.
    </para>

@GTK_FILE_CHOOSER_ACTION_OPEN: Indicates open mode.  The file chooser
    will only let the user pick an existing file.
@GTK_FILE_CHOOSER_ACTION_SAVE: Indicates save mode.  The file chooser
    will let the user pick an existing file, or type in a new
    filename.
@GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER: Indicates an Open mode for
    selecting folders.  The file chooser will let the user pick an
    existing folder.
@GTK_FILE_CHOOSER_ACTION_CREATE_FOLDER: Indicates a mode for creating a
    new folder.  The file chooser will let the user name an existing or