Skip to content

Latest commit

 

History

History
213 lines (127 loc) · 4.64 KB

entry.rst

File metadata and controls

213 lines (127 loc) · 4.64 KB
Raw

Entry, Combox, Spinbox

Several widgets allow to enter text or numerical information in a single field.

  • the Entry widgets allows to type text
  • the Combobox allows to either type text or select text from a drop-down list
  • the Spinbox allows to select from a numerical range or from a list
  • the Scale allows to use a slider to choose a value

image

entry0.py<entry0.py>

Since these widgets are very similar, we treat them in the same section.

Entry widget

An entry widget presents the user an empty field where he can enter a text value.

Each ttk.Entry object has these options:

  • parent - the parent object
  • textvariable - the text variable to hold the entered string
  • width - the numbers of characters
  • show - to indicate * for passwords

The Entry widget does not have a text or image option. You have to use an additional label widget instead.

image

entry1.py

entry1.py<entry1.py>

A better Entry class

It's time now to define a new and better Entry class which can do everything in one line:

Entry('First name:', 'print(self.var.get())')

This new class has the attributes:

  • label - to automatically add label in front of the entry field
  • cmd - to execute a command string when hitting the Return key
  • val - a default value

image

The command function evaluates the expression entered and displays the result in the following label widget:

Entry('Enter expression', 'App.res["text"] = eval(self.var.get())')
App.res = Label('Result')

entry2.py

entry2.py<entry2.py>

Now let's see how this class is defined

tklib.py

Combobox

A combobox combines an entry widget with a list of choices. The user can either select text from a drop-down menu or write his own text.

The first combobox allows to also enter your own text, while the second one is restricted to chose an item from the drop-down menu by setting state='readonly'.

image

The Combobox class has the options

  • parent - for the parent object
  • textvariable - for the variable which stores the value
  • values - for the items list
  • state - to indicate readonly

Standard Combobox

combo1.py

combo1.py<combo1.py>

A better Combobox class

A combobox combines a list of choices with an entry. The user can select from the list, but he can also enter directly a value.

image

The items list can be a:

  • semicolon-separated string
  • integer list: [2005, 2006, 2007]
  • list expression (list(range10))

combo2.py

combo2.py<combo2.py>

How is this new class defined ?

tklib.py

Exemple

image

combo3.py

combo3.py<combo3.py>

Another exemple

image

The items list can be a:

  • semicolon-separated string
  • tuple
  • list
  • list expression (list(range10))

The command function can be either a string to execute or a function.

combo4.py

combo4.py<combo4.py>

Spinbox

A spinbox widget is an entry widget with built-in up and down buttons that are used to either modify a numeric value or to select among a set of values. The widget implements all the features of the entry widget.

image

spinbox1.py

spinbox1.py<spinbox1.py>

image

spinbox2.py

spinbox2.py<spinbox2.py>

Scale

A scale widget provides a way for users to choose a numeric value through direct manipulation.

image

scale2.py

scale2.py<scale2.py>

Final implementation

The four classes Entry, Combobox, Spinbox and Scale have two common parts:

  • adding an optional label in front of the widget
  • adding a callback function

This two functions can be placed in a specal class called EntryMixin, which serves as second parent class for the 4 entry classes.

tklib.py

This allows to make the Entry class much shorter.

tklib.py

The other class definitions are as follows:

tklib.py

tklib.py

tklib.py