[tkinter] think in tkinter (9)

在本程序中, 我们来看一下容器嵌套. 我们会创建一组容器, 一个嵌套一个: bottom_frame, left_frame和right_frame.

这些容器里啥控件也没有. 因为容器会自动缩放, 所以它里面没控件时, 就会缩得完全看不到. 但我们可以通过"height"和"width"属性来给它们设置一个初始大小.

注意, 我们并没有为所有的容器设置大小. 比如myContainer1, 我们就没有设置. 但我们将它所有的子容器都设置了大小, 所以它的大小会随着子容器的变化而变化.

在之前的程序中, 我们都把控件塞到容器中, 但在本程序中, 我们只创建容器, 并且给他们设置不同的大小, 位置和背景色.

我们还会给每个容器添加一个边框, 这会让我们很好的区分出它们: bottom_frame, left_frame和right_frame. 而其他的容器(如top_frame和buttons_frame)则不添加这个边框.

*代码示例*

程序运行时, 你会看到一堆不同背景色的容器.

from Tkinter import *

class MyApp:
    def __init__(self, parent):

        self.myParent = parent

        ### Our topmost frame is called myContainer1
        self.myContainer1 = Frame(parent) ###
        self.myContainer1.pack()

        #------ constants for controlling layout ------
        button_width = 6      ### (1)

        button_padx = "2m"    ### (2)
        button_pady = "1m"    ### (2)

        buttons_frame_padx =  "3m"   ### (3)
        buttons_frame_pady =  "2m"   ### (3)
        buttons_frame_ipadx = "3m"   ### (3)
        buttons_frame_ipady = "1m"   ### (3)
        # -------------- end constants ----------------

        ### We will use VERTICAL (top/bottom) orientation inside myContainer1.
        ### Inside myContainer1, first we create buttons_frame.
        ### Then we create top_frame and bottom_frame.
        ### These will be our demonstration frames.

        # buttons frame
        self.buttons_frame = Frame(self.myContainer1) ###
        self.buttons_frame.pack(
            side=TOP,   ###
            ipadx=buttons_frame_ipadx,
            ipady=buttons_frame_ipady,
            padx=buttons_frame_padx,
            pady=buttons_frame_pady,
            )

        # top frame
        self.top_frame = Frame(self.myContainer1)
        self.top_frame.pack(side=TOP,
            fill=BOTH,
            expand=YES,
            )  ###

        # bottom frame
        self.bottom_frame = Frame(self.myContainer1,
            borderwidth=5,  relief=RIDGE,
            height=50,
            background="white",
            ) ###
        self.bottom_frame.pack(side=TOP,
            fill=BOTH,
            expand=YES,
            )  ###


        ### Now we will put two more frames, left_frame and right_frame,
        ### inside top_frame.  We will use HORIZONTAL (left/right)
        ### orientation within top_frame.

        # left_frame
        self.left_frame = Frame(self.top_frame, background="red",
            borderwidth=5,  relief=RIDGE,
            height=250,
            width=50,
            ) ###
        self.left_frame.pack(side=LEFT,
            fill=BOTH,
            expand=YES,
            )  ###


        ### right_frame
        self.right_frame = Frame(self.top_frame, background="tan",
            borderwidth=5,  relief=RIDGE,
            width=250,
            )
        self.right_frame.pack(side=RIGHT,
            fill=BOTH,
            expand=YES,
            )  ###


        # now we add the buttons to the buttons_frame
        self.button1 = Button(self.buttons_frame, command=self.button1Click)
        self.button1.configure(text="OK", background= "green")
        self.button1.focus_force()
        self.button1.configure(
            width=button_width,  ### (1)
            padx=button_padx,    ### (2)
            pady=button_pady     ### (2)
            )

        self.button1.pack(side=LEFT)
        self.button1.bind("", self.button1Click_a)

        self.button2 = Button(self.buttons_frame, command=self.button2Click)
        self.button2.configure(text="Cancel", background="red")
        self.button2.configure(
            width=button_width,  ### (1)
            padx=button_padx,    ### (2)
            pady=button_pady     ### (2)
            )

        self.button2.pack(side=RIGHT)
        self.button2.bind("", self.button2Click_a)

    def button1Click(self):
        if self.button1["background"] == "green":
            self.button1["background"] = "yellow"
        else:
            self.button1["background"] = "green"

    def button2Click(self):
        self.myParent.destroy()

    def button1Click_a(self, event):
        self.button1Click()

    def button2Click_a(self, event):
        self.button2Click()


root = Tk()
myapp = MyApp(root)
root.mainloop()