Android自带的日志类不支持显示文件名和行号，调试时很不方便。而第三方日志库往往又太重。所以自己对Android自带的日志类做了一个简单的封装，主要是调试时使用，不考虑日志丢失和性能问题。日志的输出如下：

08-12 13:26:25.557 31285 31285 D com.tq.test: [TestFragment.kt:85 com.tq.test.fragment.TestFragment$subscribeUi$5.onChanged] foo bar

用法如下：

// 在Activity或Fragment中

val someValue = "abc";

getLogger().debug(someValue)

getLogger().debug(someValue, x, y, z)

getLogger().error(ex)

// CrashHandler

package com.tq.test

import android.os.Process

import com.tq.test.utility.Logger

class DefaultExceptionHandler(

private val packageName: String,

private val next: Thread.UncaughtExceptionHandler? = null

): Thread.UncaughtExceptionHandler {

override fun uncaughtException(thread: Thread, error: Throwable) {

val logger = Logger.getLogger(packageName)

logger.error(error, "uncaught exception", thread)

next?.uncaughtException(thread, error)

Process.killProcess(Process.myPid())

}

}

Thread.setDefaultUncaughtExceptionHandler(DefaultExceptionHandler(

getPackageName(),

Thread.getDefaultUncaughtExceptionHandler()

))

源代码如下：

package com.tq.utility

import androidx.appcompat.app.AppCompatActivity

import androidx.fragment.app.Fragment

import android.content.Context

import android.util.Log

class Logger private constructor(val defaultTag: String = "") {

fun debug(vararg values: Any?) = Log.d(defaultTag, makeMessage(values))

fun info(vararg values: Any?) = Log.i(defaultTag, makeMessage(values))

fun warn(vararg values: Any?) = Log.w(defaultTag, makeMessage(values))

fun error(error: Throwable, vararg values: Any?) = Log.e(defaultTag, makeMessage(values), error)

private fun makeMessage(values: Array): String {

// TOOD handle native method

var fileName = "unknown"

var lineNumber = -1

var className = "unknown"

var methodName ="unknown"

val throwable = Throwable()

val stacks = throwable.getStackTrace()

val depth = 2

if (stacks.size > depth) {

val stack = stacks[depth]

fileName = stack.getFileName()

lineNumber = stack.getLineNumber()

className = stack.getClassName()

methodName = stack.getMethodName()

}

val valueString = values.map{ it?.toString() ?: "null" }.joinToString()

return "[$fileName:$lineNumber $className.$methodName] $valueString"

}

companion object {

fun getLogger(tag: String): Logger {

return Logger(tag)

}

fun getLogger(context: Context) = getLogger(context.getPackageName())

}

}

fun AppCompatActivity.getLogger() = Logger.Companion.getLogger(this)

fun Fragment.getLogger() = Logger.Companion.getLogger(activity!!)