Скачать или смотреть Solving Cannot find setter Error in Custom Views with Data Binding in Android

Learn how to resolve the `Cannot find setter` error when using Data Binding with custom views in Android by implementing a BindingAdapter.
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This video is based on the question https://stackoverflow.com/q/71393329/ asked by the user 'Emanuel' ( https://stackoverflow.com/u/1506153/ ) and on the answer https://stackoverflow.com/a/71394348/ provided by the user 'Satish Navada' ( https://stackoverflow.com/u/1954723/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the Cannot find setter Error in Custom Views with Data Binding in Android

Creating custom views in Android can be a powerful way to design your app's interface. However, when working with data binding, you might run into some tricky issues, such as the infamous Cannot find setter error. In this post, we’ll break down this problem and provide you with a clear solution.

The Problem

You have designed a custom layout for a toolbar utilizing a class that extends AppBarLayout. Your aim was to set the title of this toolbar using a custom attribute in XML. While it works perfectly when you set a hardcoded value in the XML, you encounter difficulty when attempting to dynamically bind the title from your ViewModel. This results in the error message:

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This suggests that Android doesn't know how to convert the value from your ViewModel into the expected type for the custom view's setter.

The Solution

To solve this, you will need to create a BindingAdapter. A BindingAdapter allows you to define custom behaviors for binding operations in your views. Below, we will guide you through implementing this solution step-by-step.

Step 1: Create a BindingAdapter

In your MyAppBarLayoutCustomView class or in a separate file, define a BindingAdapter as follows:

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Step 2: Implement the Setter Method in Your Custom View

Your custom view needs a method that assigns the title to the toolbar. Ensure you implement this method to accept your Integer resource ID and convert it to a String. Here's how you might do it:

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Step 3: Update Your XML for Data Binding

With the BindingAdapter defined, you can now continue using data binding in your XML layout:

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Step 4: Update Your ViewModel

Make sure your ViewModel has the LiveData property correctly set up, returning the desired title from its resource ID.

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Conclusion

By following these steps, you should successfully resolve the Cannot find setter error in your Android custom view, allowing you to dynamically bind the title from your ViewModel. Utilize BindingAdapters to create more adaptable and reusable components in your application. Happy coding!