How to add tags to Timber log messages in Kotlin Android

How to add tags to Timber log messages in Kotlin Android.

Logging is an essential part of the software development process as it helps in debugging and understanding the flow of code. Timber is a popular logging library in Android that provides a convenient way to log messages. In addition to logging messages, Timber also allows us to add tags to log messages, making it easier to filter and identify specific logs.

In this tutorial, we will learn how to add tags to Timber log messages in Kotlin Android. We will go through the step-by-step process and provide multiple code examples where applicable.

Step 1: Set Up Timber in your Android Project

Before we can start using Timber, we need to set it up in our Android project. Follow these steps to add Timber to your project:

1. Open your app-level build.gradle file.
2. Add the following line inside the dependencies block:

implementation 'com.jakewharton.timber:timber:4.7.1'

3. Sync the project with Gradle to download the Timber library.

Step 2: Create a Custom Timber Tree

To add tags to Timber log messages, we need to create a custom Timber tree that extends Timber.DebugTree. Follow these steps to create a custom Timber tree:

1. Create a new Kotlin class named TaggedDebugTree.

import timber.log.Timber

class TaggedDebugTree : Timber.DebugTree() {
    override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
        super.log(priority, "${tag ?: "TaggedDebugTree"} - $message", t)
    }
}

2. In the log function, we override the default behavior of Timber.DebugTree to include the tag in the log message.

Step 3: Initialize Timber with the Custom Tree

To use our custom Timber tree, we need to initialize Timber in our application class. Follow these steps to initialize Timber:

1. Open your application class (usually named MyApplication.kt).
2. Add the following code inside the onCreate method:

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

class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()

        if (BuildConfig.DEBUG) {
            Timber.plant(TaggedDebugTree())
        }
    }
}

3. Make sure to replace MyApplication with the name of your application class.

Step 4: Log Messages with Tags

Now that we have set up Timber with the custom tree, we can start logging messages with tags. Here's an example of how to log a message with a tag:

import timber.log.Timber

Timber.tag("MainActivity").d("This is a debug log message.")

In the example above, we use the tag function from Timber to specify the tag for the log message. The d function is used to log a debug message.

Step 5: Filter Logs by Tags

Logging messages with tags allows us to filter logs based on specific tags. To filter logs by tags, follow these steps:

1. Open Logcat in Android Studio.
2. In the search bar, enter the tag you want to filter by (e.g., "MainActivity").
3. Only logs with the specified tag will be displayed.

This makes it easier to focus on specific log messages when analyzing the app's behavior.

Conclusion

In this tutorial, we learned how to add tags to Timber log messages in Kotlin Android. We went through the step-by-step process, including setting up Timber, creating a custom Timber tree, initializing Timber with the custom tree, logging messages with tags, and filtering logs by tags. Adding tags to log messages can greatly improve the readability and organization of logs, making it easier to debug and analyze the app's behavior.