Yes, modifying the source code of mobile apps can enable real-time monitoring of user behavior. **Existing Research** Researchers have demonstrated that modifying the source code of apps can collect users’ personal data, such as location, contacts, and browsing history[1]. In addition, studies have shown that malicious apps can exploit vulnerabilities to collect user data and send it to remote servers[2]. **Methods** To implement real-time user behavior monitoring, the following steps can be taken: 1. **Modify application code**: Developers can integrate monitoring code into the source code of the app, allowing the app to collect user-generated data, such as click, scroll, and input events. 2. **Implement a data transmission mechanism**: The modified app can use Web API, HTTPS, or other protocols to transmit the collected data to a remote server for processing and analysis. 3. **Use data analysis tools**: The remote server can use machine learning algorithms, statistical methods, and other data analysis tools to analyze the collected data and extract insightful information. **Challenges of Real-Time Monitoring** However, real-time monitoring of user behavior also faces several challenges: 1. **Data processing**: Collecting and processing large amounts of user data may lead to performance issues, delays, and data loss. 2. **User privacy concerns**: Monitoring user behavior may raise user privacy concerns, especially without proper consent and transparency. 3. **Platform restrictions**: Restrictions on mobile platforms, such as iOS and Android, can hinder data collection and transmission, especially if the modified applications do not comply with the platform’s guidelines and regulations. **Conclusion** Modifying the source code of mobile applications can enable real-time monitoring of user behavior, but this raises several challenges, including data processing, user privacy issues, and platform restrictions. Developers must prioritize transparency, consent, and user well-being when collecting and analyzing user data. **References** [1] F. Liu et al. (2019). Measurement of privacy breaches in mobile applications. Paper presented at the 26th International Network and Distributed System Security Symposium (NDSS). [2] Y. Zeng et al. (2020). Behavioral analysis for mobile malware detection. Paper presented at the 29th Annual Conference on Malicious and Unwanted Software (MALCON). Note: While modifying application code can enable user behavior monitoring, it is important to ensure that such activities are transparent, compliant with regulations, and with user consent.