5 Best Ways to Create a Banner in KivyMD Python

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💡 Problem Formulation: In the realm of mobile app development with KivyMD in Python, a common requirement is to create a visually appealing banner that conveys information effectively. These banners need to be responsive, interactive, and aesthetically integrated into the application’s design. The input is often a set of text or images, while the desired output is a user-friendly banner that functions within a KivyMD app environment.

Method 1: Use the MDBanner widget

KivyMD offers a convenient way to create banners with the MDBanner widget. This widget is specifically designed for the purpose of displaying banners within your application. Its flexibility allows you to incorporate text, buttons, and even images while providing a straightforward API for developers.

Here’s an example:

from kivymd.app import MDApp
from kivymd.uix.banner import MDBanner

class MyApp(MDApp):
    def build(self):
        banner = MDBanner(text=["Your banner text here"])
        return banner

MyApp().run()

Output: A banner with the text “Your banner text here” is displayed in your KivyMD app.

This MDBanner instance creates a simple text-based banner. The text attribute is a list, allowing multiple items to be displayed within the banner. This flexibility makes it easy to design banners appropriate for various scenarios just by modifying the text list.

Method 2: Adding action buttons to MDBanner

To enhance user engagement, KivyMD’s MDBanner allows for the addition of action buttons. This feature is particularly useful for providing interactivity within your banners, such as undo actions or navigation prompts.

Here’s an example:

from kivymd.app import MDApp
from kivymd.uix.banner import MDBanner

class MyApp(MDApp):
    def build(self):
        banner = MDBanner(
            text=["Your banner text here", "Additional info here"],
            buttons=[
                {"text": "CANCEL", "action": lambda *x: None},
                {"text": "RETRY", "action": lambda *x: None},
            ],
        )
        return banner

MyApp().run()

Output: A banner with action buttons “CANCEL” and “RETRY” is displayed in your KivyMD app.

In this code snippet, two action buttons are attached to the banner by passing a list of dictionaries to the buttons parameter within MDBanner. Each dictionary specifies the button text and the action to be triggered when a button is pressed. Lambda functions are used here as placeholders for actual event handling functions.

Method 3: Custom styling with KivyMD theming

KivyMD supports extensive theming options that can be applied to banners. Customizing a banner’s color scheme to match the app’s theme can result in better user interface cohesion and improved aesthetics.

Here’s an example:

from kivymd.app import MDApp
from kivymd.uix.banner import MDBanner
from kivymd.theming import ThemeManager

class MyApp(MDApp):
    theme_cls = ThemeManager()
    
    def build(self):
        self.theme_cls.primary_palette = "Blue"
        banner = MDBanner(text=["Your customized banner"])
        return banner

MyApp().run()

Output: A banner styled with the primary color palette set to blue is displayed in your KivyMD app.

The ThemeManager class from KivyMD is used to customize the application’s theme. By assigning a value to self.theme_cls.primary_palette, the primary color of the app (and consequently the banner) is set, which allows for a quick and effective way to style the banner.

Method 4: Incorporating Images in banners

In addition to text and buttons, banners can be more engaging when images are included. KivyMD’s MDBanner allows the integration of images, which can significantly enhance the visual appeal of your banner.

Here’s an example:

from kivymd.app import MDApp
from kivymd.uix.banner import MDBanner

class MyApp(MDApp):
    def build(self):
        banner = MDBanner(
            text=["Your banner text here"],
            left_action_items=[["image", lambda x: None]],
            right_action_items=[["close", lambda x: None]],
        )
        return banner

MyApp().run()

Output: A banner displaying an image on the left and a close icon on the right in your KivyMD app.

By providing a list of tuples for left_action_items and right_action_items, we can easily place images or icons on the banner. Each tuple contains the source of the image or icon and an associated callback function executed when the item is pressed.

Bonus One-Liner Method 5: Quick Banner with an Icon

For a quick and simple banner implementation, KivyMD allows creating a banner with a pre-set icon to convey the purpose instantly, using minimal code.

Here’s an example:

from kivymd.app import MDApp
from kivymd.uix.banner import MDBanner

MyApp().run(lambda: MDBanner(text=["Quick banner"], icon="information").open())

Output: A rapid deployment of a banner with an “information” icon and a succinct message is shown.

This concise one-liner is possible due to the lambda function that opens up a banner with preset text and an icon. It is a quick solution for simple notifications that require minimal user interaction.

Summary/Discussion

  • Method 1: MDBanner Widget. Strengths: Specifically designed for banner displays in KivyMD, straightforward to use. Weaknesses: Basic, less customizable compared to complex banner setups.
  • Method 2: Action Buttons. Strengths: Interactive, engaging for users. Weaknesses: Requires additional coding to handle button events.
  • Method 3: Custom Styling. Strengths: Enhances visual harmony, extensive customization options. Weaknesses: May require a good understanding of design principles.
  • Method 4: Incorporating Images. Strengths: Visually appealing, can convey messages quickly. Weaknesses: Difficulties might arise when dealing with image scaling and responsiveness.
  • Method 5: Quick Banner One-Liner. Strengths: Rapid deployment, efficient for simple banners. Weaknesses: Limited functionality and customization.