Clickable Line Numbers in Timber Logs: Boosting Your Android Debugging Experience

type

Post

status

Published

date

Apr 16, 2023

slug

android-logging-clickable-line-numbers-timber

summary

Improve Android logging with a custom debug tree adding clickable line numbers to Timber log messages. Follow our guide for better code navigation and debugging.

Enhance Your Android Logging with Clickable Line Numbers using Timber

As an Android developer, you're likely familiar with how crucial logging is for debugging and maintaining your applications. One popular logging library is Timber, created by Jake Wharton. While Timber is powerful and easy to use, there's always room for improvement. In this blog post, we'll show you how to create a custom debug tree that adds clickable line numbers to your Timber log messages, making it even easier to navigate your code and identify issues.

Timber: A Brief Overview

Timber is an extensible logging library for Android that provides utility on top of Android's native Log class. It simplifies logging by allowing you to plant various "trees" that determine how logs are processed. You can learn more about Timber and its features on its GitHub repository: https://github.com/JakeWharton/timber

Step 1: Create a Custom Debug Tree

To start, create a new file named ClickableLineNumberDebugTree.kt and add the following code:


package com.example.bettertimberlogsandroid

import timber.log.Timber

class ClickableLineNumberDebugTree : Timber.DebugTree() {

    override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
        findLogCallStackTraceElement()?.let { element ->
            val lineNumberInfo = "(${element.fileName}:${element.lineNumber})"
            val updatedMessage = "$lineNumberInfo: $message"
            super.log(priority, tag, updatedMessage, t)
        } ?: run {
            super.log(priority, tag, message, t)
        }
    }

    override fun createStackElementTag(element: StackTraceElement): String? {
        return element.className
    }

    private fun findLogCallStackTraceElement(): StackTraceElement? {
        val stackTrace = Throwable().stackTrace
        var foundDebugTree = false

        return stackTrace.firstOrNull { element ->
            if (element.className.contains("ClickableLineNumberDebugTree")) {
                foundDebugTree = true
                false
            } else {
                foundDebugTree && !element.className.contains("Timber")
            }
        }
    }
}

This custom debug tree extends Timber's DebugTree class and overrides the log method. It first locates the stack trace element corresponding to the log call and then adds the file name and line number to the message. This makes the line number clickable in the Logcat output.

Making it clickable

val lineNumberInfo = "(${element.fileName}:${element.lineNumber})”

To make the line number clickable in Android Studio's logcat, the log message format should include the file name and line number in a specific format: filename.extension:line_number.

Step 2: Plant the Custom Debug Tree

In your Application class, for example, App.kt, plant the custom debug tree:


package com.example.bettertimberlogsandroid

import android.app.Application
import timber.log.Timber

class App : Application() {
    override fun onCreate() {
        super.onCreate()
        Timber.plant(ClickableLineNumberDebugTree())
        Timber.d("Hello Timber")
    }
}

Step 3: Use Timber in Your Activities

Now, you can use Timber in your activities, like MainActivity.kt, to log messages:


class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        Timber.d("Hello MainActivity")
        setContent {
            BetterTimberLogsAndroidTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    Greeting("Android")
                }
            }
        }
    }
}

When you log a message using Timber, you'll see the log message with the line number in Logcat. Clicking the line number will redirect you to the file and the specific line number in your code.

Demo of Clickable Line Numbers in Timber

Conclusion

By extending Timber's functionality with a custom debug tree, you can make your Android development experience even better. With clickable line numbers in your log messages, navigating your code and identifying issues becomes a breeze

Reference

Code Example: https://github.com/androiddevnotes/better-timber-logs-android/tree/6112f9d5ccd1957db39189c417cbdf9a68102357

Timber:

timber

JakeWharton • Updated May 28, 2023