Context:

Mobile applications have to continuously evolve in order to meet new user requirements and technological changes. Addressing these constraints may lead to poor implementation and design choices, known code smells. Code refactoring is a key practice that is employed to ensure that the intent of a code change is properly achieved without compromising internal software quality. While previous studies have investigated the impact of refactoring on traditional code smells in desktop applications, little attention has been paid to the impact of refactoring activities in mobile application development.

Objective:

We aim to develop a broader understanding of the impact of refactoring activities on Android and traditional code smells in Android apps.

Method:

We conduct a longitudinal empirical study by analyzing the evolution history of five open-source Android apps comprising 652 releases and exhibiting a total of 9,600 refactoring operations. We consider 15 common Android smell types and 10 common traditional Object-Oriented (OO) code smell types to provide a broad overview of the relationship between refactoring and code smells.

Results:

We find that code smells are widespread across Android applications, but smelly classes are not particularly targeted by refactoring activities and, when they are, it is rare for refactoring to actually remove a smell.

Conclusions:

These somewhat surprising results indicate that it is critical to understand better the real quality issues that Android developers face, and to develop a model of code smells and refactoring that can better address their needs in practice.

中文翻译：

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重构对安卓应用程序影响的纵向研究

语境：

移动应用程序必须不断发展，以满足新的用户需求和技术变革。解决这些限制可能会导致糟糕的实现和设计选择，以及已知的代码异味。代码重构是一种关键实践，用于确保在不影响内部软件质量的情况下正确实现代码更改的意图。虽然之前的研究调查了重构对桌面应用程序中传统代码异味的影响，但很少关注重构活动在移动应用程序开发中的影响。

客观的：

我们旨在更广泛地了解重构活动对 Android 的影响以及 Android 应用程序中的传统代码异味。

方法：

我们通过分析包含 652 个版本和总共 9,600 次重构操作的五个开源 Android 应用程序的演化历史进行纵向实证研究。我们考虑了 15 种常见的 Android 气味类型和 10 种常见的传统面向对象 (OO) 代码气味类型，以提供重构和代码气味之间关系的广泛概述。

结果：

我们发现代码异味在 Android 应用程序中很普遍，但异味类并不是重构活动的特别目标，当它们出现时，重构很少能真正消除异味。

结论：

这些有些出人意料的结果表明，更好地了解 Android 开发人员面临的实际质量问题，并开发一种可以在实践中更好地满足他们需求的代码异味和重构模型至关重要。