Events（事件）

Events are given as strings, using a special event syntax:
事件以字符串的方式给出，使用特殊的事件语法:
<modifier-type-detail>
Event Formats（事件格式）
1、<Button-1>
在小部件上按下鼠标按钮触发事件
2、<B1-Motion>
按下按钮并移动触发事件
3、<ButtonRelease-1>
松开按钮触发事件
4、<Double-Button-1>
鼠标点击两次后触发事件
5、<Enter>
鼠标进入小部件之后触发（不是点击或者摁enter键）
6、<Leave>
鼠标离开小部件时触发
7、<FocusIn>
Keyboard focus was moved to this widget, or to a child of this widget.
没明白这个什么意思
8、<FocusOut>
Keyboard focus was moved from this widget to another widget.
应该是跟上边意思相反但是不明白
9、<Key>
键盘输入任意键触发
10、<Return>
The user pressed the Enter key. You can bind to virtually all keys on the keyboard. For an ordinary 102-key PC-style keyboard, the special keys are Cancel (the Break key), BackSpace, Tab, Return(the Enter key), Shift_L (any Shift key), Control_L (any Control key), Alt_L (any Alt key), Pause, Caps_Lock, Escape, Prior (Page Up), Next (Page Down), End, Home, Left, Up, Right, Down, Print, Insert, Delete, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, Num_Lock, and Scroll_Lock.（不明白什么意思）
11、a
The user typed an “a”. Most printable characters can be used as is. The exceptions are space (<space>) and less than (<less>). Note that 1 is a keyboard binding, while <1> is a button binding.
12、<Shift-Up>
The user pressed the Up arrow, while holding the Shift key pressed. You can use prefixes like Alt, Shift, and Control.
13、<Configure>
The widget changed size (or location, on some platforms). The new size is provided in the width and height attributes of the event object passed to the callback.

The Event Object

The event object is a standard Python object instance, with a number of attributes describing the event.
事件属性：
widget
The widget which generated this event. This is a valid Tkinter widget instance, not a name. This attribute is set for all events.（生成此事件的小部件。这是一个有效的Tkinterwidget属性，不是一个名称。这个属性可以为所有事件设置）

x, y
The current mouse position, in pixels.（当前鼠标位置，以像素为单位。x，y轴）

x_root, y_root
The current mouse position relative to the upper left corner of the screen, in pixels.（当前鼠标位置相对于屏幕左上角的像素）

char
The character code (keyboard events only), as a string.（字符代码(只有键盘事件)，作为字符串）

keysym
The key symbol (keyboard events only).（关键符号(只有键盘事件)）

keycode
The key code (keyboard events only).（关键代码(只有键盘事件)）

num
The button number (mouse button events only).（按钮编号(鼠标按键事件)）

width, height
The new size of the widget, in pixels (Configure events only).（小部件的新大小，以像素(仅配置事件)）

type
The event type.（事件类型）

Instance and Class Bindings(实例和类绑定)
you can create bindings on four different levels:

1、the widget instance, using bind.

2、the widget’s toplevel window (Toplevel or root), also using bind.

3、the widget class, using bind_class (this is used by Tkinter to provide standard bindings).

4、the whole application, using bind_all.
首先，在这四个层次中，Tkinter选择可用绑定的 “最接近的匹配”。例如，如果为<Key>和 <Return>事件创建实例绑定，则只有按下Enter键才会调用第二个绑定。
例子1：
#-*-coding:utf-8-*-
#author:wangxing

#捕获键盘事件

import Tkinter

root = Tkinter.Tk()
def key(event):
print 'pressed',repr(event.char)
def callback(event):
frame.focus_set()
print 'clicked at',event.x_root,event.y_root, event.num
x = event.x
y = event.y
return x,y
def enter():
print 'test'
frame = Tkinter.Frame(root,width=100,height=100,bg='red')
'''
frame.bind("<Key>",key)
frame.bind("<Button-1>",callback)
frame.bind("<B1-Motion>",callback)
frame.bind("<ButtonRelease-1>",callback)
frame.bind("<Double-Button-1>",callback)
frame.bind("<Enter>",callback)
frame.bind("<Leave>",callback)
'''
frame.bind("<FocusIn>",key)
frame.bind("<Button-1>",callback)
frame.pack()
root.mainloop()
例子2：
#-*-coding:utf-8-*-
#author:wangxing

'''Capturing clicks in a window(在窗口中捕获单击的位置下，y)'''
from Tkinter import *

root = Tk()

def callback(event):
print "clicked at", event.x, event.y

frame = Frame(root, width=100, height=100,bg='black')
frame.bind("<Button-1>", callback)
frame.pack()
root.mainloop()

Protocol（协议）
除了事件绑定之外，Tkinter还支持称为协议处理程序的机制。
最常用的协议称为WM_DELETE_WINDOW，用于定义用户使用窗口管理器明确关闭窗口时发生的情况：
例子：
#-*-coding:utf-8-*-
#author:wangxing

import Tkinter,tkMessageBox

def callback():
if tkMessageBox.askyesno('退出','你确定要退出?'):
root.destroy()

root = Tkinter.Tk()
root.protocol("WM_DELETE_WINDOW",callback)
root.mainloop()

Standard Dialogs（标准对话框）
The tkMessageBox module provides an interface to the message dialogs.

The easiest way to use this module is to use one of the convenience functions: showinfo, showwarning, showerror, askquestion, askokcancel, askyesno, or askretrycancel.

They all have the same syntax:
tkMessageBox.function(title, message [, options]).

Message Box Options（选项）
1、default constant

Which button to make default: ABORT, RETRY, IGNORE, OK, CANCEL, YES, or NO (the constants are defined in the tkMessageBox module).

2、icon (constant)

Which icon to display: ERROR, INFO, QUESTION, or WARNING

3、message (string)

The message to display (the second argument to the convenience functions). May contain newlines.

4、parent (widget)

Which window to place the message box on top of. When the message box is closed, the focus is returned to the parent window.

5、title (string)

Message box title (the first argument to the convenience functions).

6、type (constant)

Message box type; that is, which buttons to display: ABORTRETRYIGNORE, OK, OKCANCEL, RETRYCANCEL, YESNO, or YESNOCANCEL.

例子：

#-*-coding:utf-8-*-
#author:wangxing

import Tkinter

master = Tkinter.Tk()
w = Tkinter.Canvas(master,width=200,height=100)
w.pack()

w.create_line(0,0,200,100,fill='blue')
w.create_line(0,100,200,0,fill='red',dash=(2,4))      #dash破折号
w.create_rectangle(50,25,150,75,fill='red')

Tkinter.mainloop()

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