問題描述

我已經嘗試讓我的標簽自動更新很長一段時間了，我已經閱讀了十幾個 StackOverflow 問題，但無濟于事.

I have been trying to get my labels to auto-update themselves for quite a while now and I have read over a dozen StackOverflow questions but to no avail.

我有一個全局對象，其中包含一個整數值，我希望在其中一個小部件類中顯示該值并帶有標簽.

I have an global object that contains an integer value that I want to be displayed with a label inside of one of my widget classes.

小部件類如下所示:

class Battle(Widget):

    def __init__(self, **kwargs):
        super(Battle, self).__init__(**kwargs)

        #Enemy Stats
        self.enemyBar = BoxLayout(orientation="horizontal", size=(Window.width, Window.height/8), center_y = Window.height - self.height/2)
        self.enemyBar.add_widget(Label(text=enemy.name))

        #Enemy Health Label
        health_label = Label(text=str(enemy.health))
        self.enemyBar.add_widget(health_label)
        self.add_widget(self.enemyBar)


    def update_health(instance, value):
        health_label.text = str(enemy.health) #<-- Error happens here

    enemy.bind(health=update_health)

當 enemy.health 的值在程序中改變時，我希望我的標簽也改變.我不想使用任何 kivy 語言，因為我更喜歡只有一個主 python 文件.

When the value of enemy.health is changed in the program, I want my label to change as well. I do not want to use any of the kivy language because I prefer having just one main python file.

敵人對象是使用實體類創建的.這是實體代碼:

The enemy object is created with an entity class. Here is the entity code:

class entity(Widget):
    #entity creation
    health = NumericProperty() 

    def __init__(self, health):
        self.health = health

當我運行代碼時，我按下一個按鈕，該按鈕調用一個改變敵人生命值的函數，然后我得到一個錯誤:

When I run the code I press a button that calls a function that changes the enemy health and then I get an error:

未定義全局名稱health_label"

不知何故，當調用 update_health 函數時，程序看不到在 init 中創建的 health_label 變量.

Somehow, when the update_health function is called, the program doesn't see the health_label variable that was created in the init.

推薦答案

需要使用bind方法，類似如下

You need to use the bind method, something like the following

health_label = Label(text=enemy.health)
self.enemyBar.add_widget(health_label)
def update_health(instance, value):
    health_label.text = str(enemy.health)
enemy.bind(health=update_health)

這只是我腦海中的一個基本示例，它可以根據您的程序結構變得更簡潔.如果enemy.health 是一個字符串，你可以這樣做 enemy.bind(health=health_label.setter('text')).

This is just a basic example off the top of my head, it can be made neater depending on the structure of your program. If enemy.health is a string, you can just do enemy.bind(health=health_label.setter('text')).

為此，health 屬性必須是 kivy 屬性:

For this to work, the health attribute must be a kivy property:

class Enemy(Something):
    health = StringProperty('')

在您的代碼中，敵人似乎是一個全局對象.很可能有更好的方法來做到這一點.另外，我建議使用 kv 語言 - 將代碼放在一個文件中并沒有任何特殊價值(事實上，一旦它變得不平凡，它通常被認為是不好的做法)，并且 kv 使很多事情變得更容易，而 python 只是'不適合某些任務.

In your code it seems that enemy is a global object. There is quite likely a better way to do that. Also, I recommend using kv language - there is not really any special value in putting your code in one file (indeed, it's commonly considered bad practice once it gets non-trivial), and kv makes a lot of things easier where python just isn't suited to certain tasks.

這篇關于Kivy - 將標簽文本綁定到變量(僅限 Python)的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！