第十二章 圖形用戶界面

GUI就是包含按鈕、文本框等控件的窗口
Tkinter是事實(shí)上的Python標(biāo)準(zhǔn)GUI工具包

創(chuàng)建GUI示例應(yīng)用程序

初探

導(dǎo)入tkinter

import tkinter as tk

也可導(dǎo)入這個(gè)模塊的所有內(nèi)容

from tkinter import *

要?jiǎng)?chuàng)建GUI，可創(chuàng)建一個(gè)將充當(dāng)主窗口的頂級(jí)組件（控件）。
為此，可實(shí)例化一個(gè)Tk對(duì)象。

top = Tk()

調(diào)用函數(shù)mainloop以進(jìn)入Tkinter主事件循環(huán)，而不是直接退出程序。

from tkinter import * top = Tk() mainloop()

效果圖如下：

創(chuàng)建按鈕，可實(shí)例化Button類。
需要使用布局管理器（也叫幾何體管理器）來(lái)顯示按鈕的位置(使用管理器pack)
按鈕也可以指定一些文本、給按鈕添加行為

from tkinter import * button = Button() button.pack() button['text'] = 'Click me!' def clicked():print("I was clicked!")mainloop()

效果圖如下：

可以不分別給屬性賦值，而使用方法config同時(shí)設(shè)置多個(gè)屬性。
button.config(text='Click me!',command=clicked)
還可使用控件的構(gòu)造函數(shù)來(lái)配置控件。
Button(text='click me too!',command=clicked).pack()

布局

對(duì)控件調(diào)用方法pack時(shí)，將把控件放在其父控件（主控件）中。

from tkinter import * Label(text="I'm in the first window!").pack() second = Toplevel() Label(second,text="I'm in the second window!").pack()

效果圖如下：
Toplevel類表示除主窗口外的另一個(gè)頂級(jí)窗口，而Label就是文本標(biāo)簽。

一列按鈕

from tkinter import * for i in range(10):Button(text=i).pack()mainloop()

效果圖如下：
要快速了解可用的選項(xiàng)，可執(zhí)行如下命令

help(Pack.config) ''' Help on function pack_configure in module tkinter:pack_configure(self, cnf={}, **kw)Pack a widget in the parent widget. Use as options:after=widget - pack it after you have packed widgetanchor=NSEW (or subset) - position widget according togiven directionbefore=widget - pack it before you will pack widgetexpand=bool - expand widget if parent size growsfill=NONE or X or Y or BOTH - fill widget if widget growsin=master - use master to contain this widgetin_=master - see 'in' option descriptionipadx=amount - add internal padding in x directionipady=amount - add internal padding in y directionpadx=amount - add padding in x directionpady=amount - add padding in y directionside=TOP or BOTTOM or LEFT or RIGHT - where to add this widget. '''

還有其他的布局管理器，具體地說(shuō)是grid和place

help(Grid.configure) ''' Help on function grid_configure in module tkinter:grid_configure(self, cnf={}, **kw)Position a widget in the parent widget in a grid. Use as options:column=number - use cell identified with given column (starting with 0)columnspan=number - this widget will span several columnsin=master - use master to contain this widgetin_=master - see 'in' option descriptionipadx=amount - add internal padding in x directionipady=amount - add internal padding in y directionpadx=amount - add padding in x directionpady=amount - add padding in y directionrow=number - use cell identified with given row (starting with 0)rowspan=number - this widget will span several rowssticky=NSEW - if cell is larger on which sides will thiswidget stick to the cell boundary ''' help(Place.config) ''' Help on function place_configure in module tkinter:place_configure(self, cnf={}, **kw)Place a widget in the parent widget. Use as options:in=master - master relative to which the widget is placedin_=master - see 'in' option descriptionx=amount - locate anchor of this widget at position x of mastery=amount - locate anchor of this widget at position y of masterrelx=amount - locate anchor of this widget between 0.0 and 1.0relative to width of master (1.0 is right edge)rely=amount - locate anchor of this widget between 0.0 and 1.0relative to height of master (1.0 is bottom edge)anchor=NSEW (or subset) - position anchor according to given directionwidth=amount - width of this widget in pixelheight=amount - height of this widget in pixelrelwidth=amount - width of this widget between 0.0 and 1.0relative to width of master (1.0 is the same widthas the master)relheight=amount - height of this widget between 0.0 and 1.0relative to height of master (1.0 is the sameheight as the master)bordermode="inside" or "outside" - whether to take border width ofmaster widget into account '''

事件處理

通過(guò)設(shè)置屬性command給按鈕指定動(dòng)作（action），這是一種特殊的事件處理。
Tkinter還提供了更通用的事件處理機(jī)制：方法bind。要讓控件對(duì)特定的事件進(jìn)行處理，可對(duì)其調(diào)用方法bind，并指定事件的名稱和要使用的函數(shù)。

點(diǎn)哪兒顯示所點(diǎn)擊的坐標(biāo)位置（鼠標(biāo)單擊事件，提供x和y坐標(biāo)）
其中是使用鼠標(biāo)左按鈕（按鈕1）單擊的事件名稱。
將這種事件關(guān)聯(lián)到函數(shù)callback。
這樣，每當(dāng)用戶在窗口top中單擊時(shí)，都將調(diào)用這個(gè)函數(shù)。向函數(shù)callback傳遞一個(gè)event對(duì)象，這個(gè)對(duì)象包含的屬性隨事件類型而異。

from tkinter import * top = Tk() def callback(event):print(event.x,event.y)top.bind('<Button-1>',callback)#結(jié)果為：'2435082162376callback' mainloop()

效果圖如下：
當(dāng)然也可以查詢幫助

help(Tk.bind) ''' Help on function bind in module tkinter:bind(self, sequence=None, func=None, add=None)Bind to this widget at event SEQUENCE a call to function FUNC.SEQUENCE is a string of concatenated eventpatterns. An event pattern is of the form<MODIFIER-MODIFIER-TYPE-DETAIL> where MODIFIER is oneof Control, Mod2, M2, Shift, Mod3, M3, Lock, Mod4, M4,Button1, B1, Mod5, M5 Button2, B2, Meta, M, Button3,B3, Alt, Button4, B4, Double, Button5, B5 Triple,Mod1, M1. TYPE is one of Activate, Enter, Map,ButtonPress, Button, Expose, Motion, ButtonReleaseFocusIn, MouseWheel, Circulate, FocusOut, Property,Colormap, Gravity Reparent, Configure, KeyPress, Key,Unmap, Deactivate, KeyRelease Visibility, Destroy,Leave and DETAIL is the button number for ButtonPress,ButtonRelease and DETAIL is the Keysym for KeyPress andKeyRelease. Examples are<Control-Button-1> for pressing Control and mouse button 1 or<Alt-A> for pressing A and the Alt key (KeyPress can be omitted).An event pattern can also be a virtual event of the form<<AString>> where AString can be arbitrary. Thisevent can be generated by event_generate.If events are concatenated they must appear shortlyafter each other.FUNC will be called if the event sequence occurs with aninstance of Event as argument. If the return value of FUNC is"break" no further bound function is invoked.An additional boolean parameter ADD specifies whether FUNC willbe called additionally to the other bound function or whetherit will replace the previous function.Bind will return an identifier to allow deletion of the bound function withunbind without memory leak.If FUNC or SEQUENCE is omitted the bound function or listof bound events are returned. '''

最終的程序

簡(jiǎn)單的GUI文本編輯器
1，需要輸入所要編輯的文本地址
2，點(diǎn)擊Open，即可打開該文本文件
3，在下方編輯欄中可隨意編輯
4，點(diǎn)擊Save即可保存

from tkinter import * from tkinter.scrolledtext import ScrolledText def load():with open(filename.get()) as file:contents.delete('1.0', END)contents.insert(INSERT, file.read())def save():with open(filename.get(), 'w') as file:file.write(contents.get('1.0', END))top = Tk() top.title("Simple Editor")contents = ScrolledText() contents.pack(side=BOTTOM, expand=True, fill=BOTH)filename = Entry() filename.pack(side=LEFT, expand=True, fill=X)Button(text='Open', command=load).pack(side=LEFT) Button(text='Save', command=save).pack(side=LEFT)mainloop()

效果圖如下：

小結(jié)

概念描述

圖形用戶界面（GUI）	GUI有助于讓應(yīng)用程序?qū)τ脩舾押谩２⒎撬械某绦蚨夹枰狦UI，但只要程序需要與用戶交互，GUI就可能很有幫助。
Tkinter	Tkinter是一個(gè)跨平臺(tái)的Python GUI工具包，成熟而且使用廣泛。
布局	通過(guò)指定組件的幾何屬性，很容易對(duì)其進(jìn)行定位，但要確保它們?cè)诟复翱诘拇笮“l(fā)生變化時(shí)做出正確的反應(yīng)，就必須使用布局管理器。
事件處理	GUI工具包中用戶觸發(fā)事件執(zhí)行的操作。要發(fā)揮作用，程序可能需要響應(yīng)某些事件，否則用戶將無(wú)法與之交互。在Tkinter中，要給組件添加事件處理程序，可使用方法bind。

總結(jié)

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