Python StringVar.trace_add方法代码示例

# 需要导入模块: from tkinter import StringVar [as 别名]
# 或者: from tkinter.StringVar import trace_add [as 别名]
def make_color_swatch(parent: tk.Frame, var: tk.StringVar, size=16) -> ttk.Label:
    """Make a single swatch."""
    # Note: tkinter requires RGB as ints, not float!

    def get_color():
        """Parse out the color."""
        color = var.get()
        if color.startswith('#'):
            try:
                r = int(color[1:3], base=16)
                g = int(color[3:5], base=16)
                b = int(color[5:], base=16)
            except ValueError:
                LOGGER.warning('Invalid RGB value: "{}"!', color)
                r = g = b = 128
        else:
            r, g, b = map(int, Vec.from_str(color, 128, 128, 128))
        return r, g, b

    def open_win(e):
        """Display the color selection window."""
        widget_sfx()
        r, g, b = get_color()
        new_color, tk_color = askcolor(
            color=(r, g, b),
            parent=parent.winfo_toplevel(),
            title=_('Choose a Color'),
        )
        if new_color is not None:
            r, g, b = map(int, new_color)  # Returned as floats, which is wrong.
            var.set('{} {} {}'.format(int(r), int(g), int(b)))

    swatch = ttk.Label(
        parent,
        relief='raised',
    )

    def update_image(var_name: str, var_index: str, operation: str):
        r, g, b = get_color()
        swatch['image'] = img.color_square(round(Vec(r, g, b)), size)

    update_image('', '', '')

    # Register a function to be called whenever this variable is changed.
    var.trace_add('write', update_image)

    utils.bind_leftclick(swatch, open_win)

    return swatch

# 需要导入模块: from tkinter import StringVar [as 别名]
# 或者: from tkinter.StringVar import trace_add [as 别名]
def widget_minute_seconds(parent: tk.Frame, var: tk.StringVar, conf: Property) -> tk.Widget:
    """A widget for specifying times - minutes and seconds.

    The value is saved as seconds.
    Max specifies the largest amount.
    """
    max_value = conf.int('max', 60)
    min_value = conf.int('min', 0)
    if min_value > max_value:
        raise ValueError('Bad min and max values!')

    values = timer_values(min_value, max_value)

    # Stores the 'pretty' value in the actual textbox.
    disp_var = tk.StringVar()

    existing_value = var.get()

    def update_disp(var_name: str, var_index: str, operation: str) -> None:
        """Whenever the string changes, update the displayed text."""
        seconds = conv_int(var.get(), -1)
        if min_value <= seconds <= max_value:
            disp_var.set('{}:{:02}'.format(seconds // 60, seconds % 60))
        else:
            LOGGER.warning('Bad timer value "{}" for "{}"!', var.get(), conf['id'])
            # Recurse, with a known safe value.
            var.set(values[0])

    # Whenever written to, call this.
    var.trace_add('write', update_disp)

    def set_var():
        """Set the variable to the current value."""
        try:
            minutes, seconds = disp_var.get().split(':')
            var.set(str(int(minutes) * 60 + int(seconds)))
        except (ValueError, TypeError):
            pass

    def validate(reason: str, operation_type: str, cur_value: str, new_char: str, new_value: str):
        """Validate the values for the text.

        This is called when the textbox is modified, to allow cancelling bad
        inputs.

        Reason is the reason this was fired: 'key', 'focusin', 'focusout', 'forced'.
        operation_type is '1' for insert, '0' for delete', '-1' for programmatic changes.
        cur_val is the value before the change occurs.
        new_char is the added/removed text.
        new_value is the value after the change, if accepted.
        """
        if operation_type == '0' or reason == 'forced':
            # Deleting or done by the program, allow that always.
            return True

        if operation_type == '1':  # Inserted text.
            # Disallow non number and colons
            if new_char not in '0123456789:':
                return False
            # Only one colon.
            if ':' in cur_value and new_char == ':':
                return False

            # Don't allow more values if it has more than 2 numbers after
            # the colon - if there is one, and it's not in the last 3 characters.
            if ':' in new_value and ':' not in new_value[-3:]:
                return False

        if reason == 'focusout':
            # When leaving focus, apply range limits and set the var.
            try:
                str_min, str_sec = new_value.split(':')
                seconds = int(str_min) * 60 + int(str_sec)
            except (ValueError, TypeError):
                seconds = min_value
            else:
                if seconds < min_value:
                    seconds = min_value
                if seconds > max_value:
                    seconds = max_value
            var.set(str(seconds))  # This then re-writes the textbox.
        return True

    validate_cmd = parent.register(validate)

    spinbox = tk.Spinbox(
        parent,
        exportselection=False,
        textvariable=disp_var,
        command=set_var,
        wrap=True,
        values=values,
        width=5,

        validate='all',
        # These define which of the possible values will be passed along.
        # http://tcl.tk/man/tcl8.6/TkCmd/spinbox.htm#M26
        validatecommand=(validate_cmd, '%V', '%d', '%s', '%S', '%P'),
    )
    # We need to set this after, it gets reset to the first one.
#.........这里部分代码省略.........