Скачать или смотреть Effortlessly Transfer Data Between an Activity and a View Class in Android

Learn how to easily transfer `float` and `boolean` values from your Android `Activity` to a custom `View` class using simple setter methods.
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This video is based on the question https://stackoverflow.com/q/62322971/ asked by the user 'AndBraz' ( https://stackoverflow.com/u/13704104/ ) and on the answer https://stackoverflow.com/a/62323677/ provided by the user 'Vivek Singh' ( https://stackoverflow.com/u/9636642/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Transfer Data Between an Activity and a View Class in Android

Transferring data between different components of an Android application can sometimes be challenging, especially for beginners. As a Java developer delving into Android, you might find yourself asking how to share values between your Activity and a custom View class. For instance, let’s explore a scenario where you want to send two float values and one boolean from the MainActivity class to a class named MyCanvas that extends View. In this post, we will break down a clear solution to achieve this effectively using setter methods.

Understanding the Problem

You have a MainActivity where you perform calculations based on user input from EditText fields. The results, xResult and yResult, need to be shared with the MyCanvas class for rendering purposes. Additionally, you have a boolean value called buttonState that you also want to convey to the MyCanvas. Using common methods like Intent and Bundle won't be efficient here since they're typically used for starting activities and passing data between them.

To tackle this issue, you can make use of setter methods in your MyCanvas class, allowing you to pass data directly.

Implementing the Solution

Step 1: Create Setter Methods in MyCanvas Class

First, you need to define setter methods in your MyCanvas class. These methods will allow external classes (like MainActivity) to set the values of cx, cy, and buttonState2. Here’s how you can implement this:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Update MainActivity Class

Now, you can modify your MainActivity class to utilize the newly created setter methods. After performing your calculations (the logic already present in your button click listener), you'll call these methods to set the values in your MyCanvas instance.

Here's how you can implement this:

[[See Video to Reveal this Text or Code Snippet]]

Key Takeaways

Setter Methods: Creating setter methods in your View class is a direct way to transfer data. This method avoids complications with Intents or Bundles when you only need to share information within the same activity's scope.

Clear Structure: Ensure that your main logic remains clear and organized by encapsulating each part's responsibility; MainActivity handles user input and calculations, while MyCanvas deals exclusively with rendering.

By following these steps, you'll find it easy to transmit data between an Activity and a View class in Android, enabling smoother functionality in your applications.