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A comprehensive guide on how to obtain selection positions of text drawn on a static layout using Android's TextView component, ensuring optimal performance in your app development.
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This video is based on the question https://stackoverflow.com/q/62160604/ asked by the user 'ATES' ( https://stackoverflow.com/u/3863756/ ) and on the answer https://stackoverflow.com/a/62273717/ provided by the user 'chef417' ( https://stackoverflow.com/u/13709773/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Getting Selection Positions of Selected Text in a Static Layout

When developing Android applications that involve text rendering, developers often encounter questions revolving around how to retrieve selection positions for text displayed on a static layout. This is especially pertinent when trying to manage user selections within a RecyclerView where each item might be a TextView. The core of the issue lies in how StaticLayouts operate and their intended use cases. Let's delve deeper into the solution and clarify how to achieve effective text manipulation in your application.

Understanding the StaticLayout Limitation

What is StaticLayout?

A StaticLayout is a low-level component used for rendering static text on a canvas. It's primarily designed for scenarios such as:

Drawing text on bitmaps

Measuring the size of a TextView prior to its creation

Despite its capabilities, the use of StaticLayout often isn't necessary for standard text display tasks. The Android Developer Guides even caution against its direct usage unless you are building a custom widget or display object.

The Missing API for Text Selection

One major drawback of StaticLayout is its lack of support for text selection. Unlike TextView, which provides methods like getSelectionStart() and getSelectionEnd() to handle user selections, StaticLayout does not offer any equivalent functionality.

Leveraging TextView Instead

The Benefits of Using TextView

In most cases, leveraging TextView for rendering text is advantageous for several reasons:

Built-in Text Selection: TextView has the necessary APIs to easily manage user interactions like text selection.

Performance Optimization: Properly recycling TextView instances within a RecyclerView using a ViewHolder pattern ensures that you won’t experience performance issues, even with large datasets. The system efficiently recycles views, only changing the text content as items are displayed or swapped, without needing to create additional TextView instances.

Implementing In RecyclerView

To handle text selection and improve maintainability, employ the following strategy within your RecyclerView:

Create ViewHolders: Ensure each item has a ViewHolder managing TextView instances efficiently.

Use TextView's Selection Methods: When users select text, utilize methods from TextView to fetch selection positions.

Maintain Performance: Monitor the RecyclerView performance to confirm that text changes do not impact the app, as you are only working with visible TextView instances.

Conclusion

In summary, while StaticLayout might present an interesting approach for rendering static text, it profoundly lacks the essential functionality for managing text selection, leaving developers better served by employing the TextView component. By utilizing this standard approach, developers can efficiently manage user selections and ensure an optimal performance within their Android applications.

With this understanding, you can confidently approach text rendering and selection management in your Android projects, ensuring your applications are not only functional but also user-friendly.