微调按钮¶

微调按钮是一个文本字段，它接受一系列值，并带有按钮，允许将该值按固定量增加或减少。

界面指南

GtkAdjustment *spin_adjustment =
  gtk_adjustment_new (0.0, 0.0, 100.0, 1.0, 5.0, 0.0);

GtkWidget *spin_button =
  gtk_spin_button_new (spin_adjustment, 1.0, 0);

spin_adjustment = Gtk.Adjustment(value=0,
                                 lower=0,
                                 upper=100,
                                 step_increment=1,
                                 page_increment=5,
                                 page_size=0)

spin_button = Gtk.SpinButton(adjustment=spin_adjustment,
                             climb_rate=1,
                             digits=0)

var spin_adjustment = new Gtk.Adjustment (0, 0, 100, 1, 5, 0);

var spin_button = new Gtk.SpinButton (spin_adjustment, 1, 0);

const spin_adjustment = new Gtk.Adjustment({
  value: 0,
  lower: 0,
  upper: 100,
  step_increment: 1,
  page_increment: 5,
  page_size: 0,
});

const spin_button = new Gtk.SpinButton({
  adjustment: spin_adjustment,
  climb_rate: 1,
  digits: 0,
});

<object class="GtkSpinButton" id="spin_button">
  <property name="adjustment">
    <object class="GtkAdjustment" id="spin_adjustment">
      <property name="value">0</property>
      <property name="lower">0</property>
      <property name="upper">100</property>
      <property name="step-increment">1</property>
      <property name="page-increment">5</property>
    </object>
  </property>
  <property name="digits">0</property>
</object>

微调按钮使用 GtkAdjustment 对象作为模型来确定它们可以显示的值的范围。微调按钮的当前值将更新 GtkAdjustment:value 属性，反之亦然。

值的变化¶

您可以使用以下信号之一来监控微调按钮值的变化

GtkSpinButton::value-changed
GtkAdjustment::value-changed
GObject::notify 在 GtkAdjustment:value 属性上

// "adj" is defined elsewhere
GtkWidget *spin_button = gtk_spin_button_new (adj, 1.0, 0);

// "on_value_changed" is defined elsewhere
g_signal_connect (spin_button, "value-changed",
                  G_CALLBACK (on_value_changed),
                  NULL);

# "adj" is defined elsewhere
spin_button = Gtk.SpinButton(adjustment=adj, climb_rate=1.0, digits=0)

# "on_value_changed" is defined elsewhere
spin_button.connect("value-changed", on_value_changed)

// "adj" is defined elsewhere
var spin_button = new Gtk.SpinButton (adj, 1, 0);

// "on_value_changed" is defined elsewhere
spin_button.value_changed.connect (on_value_changed);

// "adj" is defined elsewhere
const spin_button = new Gtk.SpinButton(adj, 1, 0);

// "on_value_changed" is defined elsewhere
spin_button.connect("value_changed", on_value_changed);

非数值微调按钮¶

调整只能在数值之间插值，但微调按钮可以显示任何类型的字母数字值，只要它可以映射到调整的范围和当前值。微调按钮可以使用 GtkSpinButton::input 信号将微调按钮的当前内容转换为数值，并使用 GtkSpinButton::output 信号将调整的数值转换为要显示的数据。

static const char *values[] = {
  "Live",
  "Laugh",
  "Love",
};

static const guint n_values = G_N_ELEMENTS (values);

static void
transform_spin_input (GtkSpinButton *self,
                      double *new_value,
                      gpointer user_data G_GNUC_UNUSED)
{
  const char *text = gtk_editable_get_text (GTK_EDITABLE (self));

  // Search for the allowed values, and map them to their
  // numerical identifier
  for (guint i = 0; i < n_values; i++)
    {
      if (g_strcmp0 (text, values[i]) == 0)
        {
          gtk_widget_remove_css_class (GTK_WIDGET (self), "error");

          *new_value = i;
          return;
        }
    }

  *new_value = 0;

  gtk_widget_add_css_class (GTK_WIDGET (self), "error");
}

static void
transform_spin_output (GtkSpinButton *self,
                       gpointer user_data G_GNUC_UNUSED)
{
  GtkAdjustment *adjustment = gtk_spin_button_get_adjustment (self);
  int value = gtk_adjustment_get_value (adjustment);

  g_assert (value >= 0 && value < n_values);

  gtk_editable_set_text (GTK_EDITABLE (self), values[value]);
}

// ...

GtkAdjustment *adj = gtk_adjustment_new (0, 0, 2, 1, 1, 0);

GtkWidget *spin_button = gtk_spin_button_new (adj, 1.0, 0);

gtk_spin_button_set_numeric (GTK_SPIN_BUTTON (spin_button), FALSE);

g_signal_connect (spin_button, "input",
                  G_CALLBACK (transform_spin_input),
                  NULL);
g_signal_connect (spin_button, "output",
                  G_CALLBACK (transform_spin_output),
                  NULL);

def transform_spin_input(spin):
    text = spin.get_text()
    if text in ["Live", "Laugh", "Love"]:
        spin.remove_css_class("error")
    else:
        spin.add_css_class("error")
    if text == "Live":
        return 0
    elif text == "Laugh":
        return 1
    elif text == "Love":
        return 2
    else:
        return 0

def transform_spin_output(spin):
    adj = spin.get_adjustment()
    value = adj.get_value()
    if value == 0:
        spin.set_text("Live")
    elif value == 1:
        spin.set_text("Laugh")
    else:
        spin.set_text("Love")

adj = Gtk.Adjustment(value=0, lower=0, upper=2,
                     step_increment=1,
                     page_increment=1,
                     page_size=0)
spin_button = Gtk.SpinButton(adjustment=adj,
                             climb_rate=1.0,
                             digits=0,
                             numeric=False)

var adj = new Gtk.Adjustment (0, 0, 2, 1, 1, 0);

var spin_button = new Gtk.SpinButton (adj, 1, 0);
spin_button.numeric = false;

spin_button.input.connect ((new_value) => {
    string text = spin_button.text;

    spin_button.remove_css_class ("error");

    if (text == "Live")
        new_value = 0;
    else if (text == "Laugh")
        new_value = 1;
    else if (text == "Love")
        new_value = 2;
    else
        new_value = 0;
        spin_button.add_css_class ("error");
        new_value = 0;
});

spin_button.output.connect (() => {
    int value = adj.value;

    assert (value >= 0 && value <= 3);

    switch (value) {
        case 0:
            spin_button.text = "Live";
        case 1:
            spin_button.text = "Laugh";
        case 2:
            spin_button.text = "Love";
    }
});

组件的常用方法¶

set_digits() 方法控制微调按钮值的精度；如果您只需要整数值，可以使用值 0。

API 参考¶

在示例中，我们使用了以下类