从 sqlite3 中检索图像并在 Kivy 图像小部件中显示 - ValueError

Question

要求

我正在尝试从数据库中检索图像并将此图像设置为 kivy 图像小部件，此操作抛出 ValueError，不确定原因。欢迎任何意见。

数据库：Sqlite3

Table 姓名：用户

列：用户 ID、用户名、用户图片

   def populate_fields(self): # NEW
      # Code retrieves text data and display in textinput fields here.

      # STEP 1: RETRIEVE IMAGE
      connection = sqlite3.connect("demo.db")
      with connection:
          cursor = connection.cursor()
          cursor.execute("SELECT UserImage from Users where 
          UserID=?",self.data_items[columns[0]]['text'] )
          image = cursor.fetchone()
          data = io.BytesIO(image[0])

      #STEP 2: SET OUTPUT TO IMAGE WIDGET
          self.image.source = data # ---> triggers an Error

错误回溯：

self.image.source = data
   File "kivy\weakproxy.pyx", line 33, in kivy.weakproxy.WeakProxy.__setattr__ (kivy\weakproxy.c:1471)
   File "kivy\properties.pyx", line 478, in kivy.properties.Property.__set__ (kivy\properties.c:5572)
   File "kivy\properties.pyx", line 513, in kivy.properties.Property.set (kivy\properties.c:6352)
   File "kivy\properties.pyx", line 504, in kivy.properties.Property.set (kivy\properties.c:6173)
   File "kivy\properties.pyx", line 676, in kivy.properties.StringProperty.check (kivy\properties.c:8613)
 ValueError: Image.source accept only str

Answer 1

执行io.BytesIO()后，data以字节为单位。使用KivyCoreImage和texture转换data.

替换

self.image.source = data

与：

self.image.texture = CoreImage(data, ext="png").texture

Image source

source
Filename / source of your image.

source is a StringProperty and defaults to None

输出

Answer 2

Ikolim 的回答很好，但更具体地说，如果你想直接将二进制图像显示到 kivy 中，你可以简单地使用 io 模块（导入 io）和 kivy 图像模块（kivy.uix.image）

检查此代码：

from kivy.uix.image import Image, CoreImage
import io


binary_data= #binary img extracted from sqlite

data = io.BytesIO(binary_data)
img=CoreImage(data, ext="png").texture

new_img= Image()
new_img.texture= img

从 sqlite3 中检索图像并在 Kivy 图像小部件中显示 - ValueError

Retrieve image from sqlite3 and display in Kivy image widget - ValueError

python

sqlite

image

kivy

kivy-language

输出