orhanobut/logger

Logger

Readable, structured logs for Android. Turn messages, collections, JSON, and XML into output that's easy to scan in Logcat.

• Pretty output with optional thread and caller information
• JSON and XML formatting
• Readable lists, maps, and arrays
• Custom tags and log filtering
• Exception stack traces
• Flexible destinations, including Logcat and files

Setup

Add Google Maven and Maven Central to your dependency repositories:

dependencyResolutionManagement {
  repositories {
    google()
    mavenCentral()
  }
}

dependencies {
  implementation("com.orhanobut:logger:2.2.0")
}

Initialize once in your application, then log:

Logger.addLogAdapter(AndroidLogAdapter())
Logger.d("hello %s", "world")

Messages

Logger.d("debug")
Logger.e("error")
Logger.w("warning")
Logger.v("verbose")
Logger.i("information")
Logger.wtf("What a Terrible Failure")

Logger.d("hello %s", "world")
Logger.d(listOf("foo", "bar"))
Logger.d(mapOf("key" to "value"))
Logger.d(intArrayOf(1, 2, 3))
Logger.json("""{"items":[1,2,3]}""")
Logger.xml("<root><item>value</item></root>")

Collection and structured output use debug priority. Include an exception and its cause with Logger.e(throwable, "message").

Set a tag for exactly one message on the calling thread:

Logger.t("Checkout").d("Order submitted")

Formatting and filtering

val format = PrettyFormatStrategy.newBuilder()
  .showThreadInfo(false) // Default: true
  .methodCount(0)        // Default: 2 caller frames
  .methodOffset(0)       // Default: 0 additional frames skipped
  .tag("MyApp")          // Default: PRETTY_LOGGER
  .build()

Logger.addLogAdapter(object : AndroidLogAdapter(format) {
  override fun isLoggable(priority: Int, tag: String?): Boolean = BuildConfig.DEBUG
})

Logger.t("Screen").d("A message tagged MyApp-Screen")

Override LogAdapter.isLoggable to filter messages by priority or tag. The example above enables logging only in debug builds. Use Logger.clearLogAdapters() before replacing the configured adapters.

For Logcat filtering, use PRETTY_LOGGER or your configured tag.

File logging

Save formatted logs to app-private storage with CsvFormatStrategy and a custom DiskLogStrategy. The sample shows the complete setup, including background writes and cleanup. App-private storage requires no storage permission.

The default DiskLogAdapter() still uses the legacy shared external-storage location. Modern Android restricts that location through scoped storage; use the sample's custom strategy for current applications.

Timber integration

Timber.plant(object : Timber.DebugTree() {
  override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
    Logger.log(priority, tag, message, t)
  }
})

License

Apache License 2.0