Android StrictMode: Catch Issues Before They Reach Production

Learn how StrictMode helps detect performance bottlenecks, resource leaks, and bad practices before they reach production.

StrictMode is a developer tool in Android that helps detect and flag potential problems in your app’s code during development. It’s a runtime policy checker that catches accidental violations that could lead to performance issues or bugs.

StrictMode monitors two main categories of violations:

• Thread Policy Violations: Detects operations on the main/UI thread that can cause frame drops or ANRs.

  • Disk reads/writes on the main thread

  • Network operations on the main thread

  • Custom slow code execution

• VM Policy Violations: Detects memory and resource-related issues in the app.

  • Activity leaks

  • SQLite object leaks

  • Closeable object leaks

Using StrictMode

Example code to enable from early in your Application, Activity, or other application component’s onCreate() method:

if (BuildConfig.DEBUG) {
    StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
              .detectDiskReads()
              .detectDiskWrites()
              .detectNetwork()
              .penaltyLog()
              .build());
    StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
              .detectLeakedSqlLiteObjects()
              .detectLeakedClosableObjects()
              .penaltyLog()
              .penaltyDeath()
              .build());
}

Note: Always enable StrictMode only in debug builds, never in production.

You can decide what should happen when a violation is detected. For example, using penaltyLog(), you can watch the output of adb logcat while you use your application to see the violations as they happen.

Few methods are:

• penaltyDeath(): Crash the whole process on violation.

• penaltyDeathOnNetwork(): Crash the whole process on any network usage.

• penaltyDialog(): Show a dialog to the developer on detected violations.

• penaltyFlashScreen(): Flash the screen during a violation.

• penaltyLog(): Log detected violations to the system log.

By integrating StrictMode into your workflow, you can build more efficient and responsive Android apps.

We must know that it is not a silver bullet. It won’t catch everything, but it helps identify common mistakes like:

• Main-Thread Disk I/O

• Main-Thread Network Calls

• Resource Leaks

• Slow Operations

Start using StrictMode from now onwards.

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Thanks

Amit Shekhar

Founder, Outcome School