Android - CrashHandler 全局异常捕获器

官网介绍如下：Thread.UncaughtExceptionHandler (Java Platform SE 8 )

用于线程因未捕获异常而突然终止时调用的处理程序接口。当线程由于未捕获异常而即将终止时，Java虚拟机将使用thread . getuncaughtexceptionhandler()查询该线程的UncaughtExceptionHandler，并调用该处理程序的uncaughtException方法，将线程和异常作为参数传递。

如果一个线程没有显式设置它的UncaughtExceptionHandler，那么它的ThreadGroup对象充当它的UncaughtExceptionHandler。如果ThreadGroup对象对处理异常没有特殊要求，它可以将调用转发给默认的未捕获异常处理程序。

?基于此点，我们可以将其应用为整个app出现异常后，没有在此处添加异常处理的时候，捕获异常并进行通用处理。

1、首先实现?Thread.UncaughtExceptionHandler 接口并创建一个单例

class CrashHandler : Thread.UncaughtExceptionHandler {

    companion object {

        private const val TAG = "CrashHandler"
        //外部存储目录
        private val INNER_PATH = Environment.getExternalStorageDirectory().path
        //自定义文件夹
        private const val SELF_FILE = "/lichang/"
        //文件名称
        private const val CRASH_FILE = "crash_error.log"

        @SuppressLint("SimpleDateFormat")
        private val formatter: DateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS")

        val sInstance by lazy(LazyThreadSafetyMode.SYNCHRONIZED) {
            CrashHandler()
        }
    }
...

2、添加初始化方法

    private var infos = mutableMapOf<String, String>()
    private var mContext: Context? = null
    private var mDefaultHandler: Thread.UncaughtExceptionHandler? = null

    //初始化
    fun init(context: Context) {
        this.mContext = context
        this.mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler()
        Thread.setDefaultUncaughtExceptionHandler(this)
    }

3、重写?uncaughtException() 方法

    override fun uncaughtException(thread: Thread, throwable: Throwable) {
        if ((!handleException(throwable)) && (this.mDefaultHandler != null)) {
            //如果代码中没有处理交给系统处理
            this.mDefaultHandler!!.uncaughtException(thread, throwable);
            return;
        }
        //延时3秒杀死进程
        Log.e(TAG, "Process will be killed in 2 seconds!");
        try {
            Thread.sleep(2000)
        } catch (e: InterruptedException) {
            Log.e(TAG, "error : ", e)
        }
        android.os.Process.killProcess(android.os.Process.myPid())
        exitProcess(1)
    }

    /**
     * 处理异常信息
     * @param throwable
     * @return
     */
    private fun handleException(throwable: Throwable?): Boolean {
        if (throwable == null) {
            return false
        }
        object : Thread() {
            override fun run() {
                Looper.prepare()
                //在此处处理出现异常的情况
                throwable.printStackTrace()
                Log.e(TAG, "出现了未捕获异常！！！")
                Looper.loop()
            }
        }.start()
        this.mContext?.let { collectDeviceInfo(it) }
        saveCrashInfo2File(throwable)
        return true
    }

    /**
     * 收集设备信息
     * @param context
     */
    private fun collectDeviceInfo(context: Context) {
        val packageInfo: PackageInfo?
        try {
            packageInfo = context.packageManager.getPackageInfo(
                context.packageName,
                PackageManager.GET_ACTIVITIES
            )
            if (packageInfo != null) {
                val versionName =
                    if (packageInfo.versionName == null) "null" else packageInfo.versionName
                val versionCode = packageInfo.versionCode.toString() + ""
                this.infos["versionName"] = versionName
                this.infos["versionCode"] = versionCode
            }
        } catch (e: PackageManager.NameNotFoundException) {
            Log.e(TAG, "an error occured when collect package info", e)
        }
        //获取Build信息
        val declaredFields: Array<Field> = Build::class.java.declaredFields
        val length = declaredFields.size
        var i = 0
        while (i < length) {
            val declaredField: Field = declaredFields[i]
            try {
                declaredField.setAccessible(true)
                this.infos[declaredField.getName()] = declaredField.get(null).toString()
            } catch (e: Exception) {
                Log.e(TAG, "an error occured when collect crash info", e)
            }
            i += 1
        }
    }

    /**
     * 保存crash信息到文件
     * @param throwable
     * @return
     */
    private fun saveCrashInfo2File(throwable: Throwable): String? {
        var throwable: Throwable? = throwable
        val crashInfos = StringBuffer()
        //添加分隔行
        crashInfos.append("\r\n")
        //添加crash时间
        crashInfos.append("Crash Time")
        crashInfos.append("=")
        crashInfos.append(formatter.format(Date(System.currentTimeMillis())))
        crashInfos.append("\r\n")
        val iterator: Iterator<Map.Entry<String, String>> = infos.entries.iterator()
        var next: Map.Entry<String, String>? = null
        while (iterator.hasNext()) {
            next = iterator.next()
            crashInfos.append(next.key)
            crashInfos.append("=")
            crashInfos.append(next.value)
            crashInfos.append("\r\n")
        }
        val exceptionInfo = StringWriter()
        val printWriter = PrintWriter(exceptionInfo)
        throwable!!.printStackTrace(printWriter)
        //循环获取throwable的栈信息
        throwable = throwable.cause
        while (throwable != null) {
            throwable.printStackTrace(printWriter)
            throwable = throwable.cause
        }
        printWriter.close()
        crashInfos.append(exceptionInfo.toString())
        try {
            System.currentTimeMillis()
            if (Environment.getExternalStorageState() == Environment.MEDIA_MOUNTED) {
                val file = File("$INNER_PATH$SELF_FILE")
                if (!file.exists()) {
                    file.mkdirs()
                }
                val fos = FileOutputStream("$INNER_PATH$SELF_FILE$CRASH_FILE", true)
                fos.write(crashInfos.toString().toByteArray())
                fos.close()
            }
            return CRASH_FILE
        } catch (e: Exception) {
            Log.e(TAG, "an error occured while writing file...", e)
        }
        return null
    }

4、在 BaseApplication 里实现，activity 里也行，但毕竟 application 生命周期更长，可以更好的捕获异常位置。

CrashHandler.sInstance.init(this)

5、验证手动抛出一个error，“?throw Exception("error")”

logcat 输出内容如下：

10:48:38.287 AndroidRuntime            D  Shutting down VM
10:48:38.293 AndroidRuntime            E  FATAL EXCEPTION: main
                                          Process: com.lichang.source, PID: 29787
                                          java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
                                          	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:563)
                                          	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
                                          Caused by: java.lang.reflect.InvocationTargetException
                                          	at java.lang.reflect.Method.invoke(Native Method)
                                          	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:553)
                                          	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)?
                                          Caused by: java.lang.Exception: error
                                          	at com.lichang.source.MainActivity.onCreate$lambda$0(MainActivity.kt:23)
                                          	at com.lichang.source.MainActivity.$r8$lambda$1d06GL5SsQcwKha8s7cR5MexWzU(Unknown Source:0)
                                          	at com.lichang.source.MainActivity$$ExternalSyntheticLambda0.onClick(Unknown Source:0)
                                          	at android.view.View.performClick(View.java:7448)
                                          	at android.view.View.performClickInternal(View.java:7421)
                                          	at android.view.View.access$3700(View.java:838)
                                          	at android.view.View$PerformClick.run(View.java:28870)
                                          	at android.os.Handler.handleCallback(Handler.java:938)
                                          	at android.os.Handler.dispatchMessage(Handler.java:99)
                                          	at android.os.Looper.loopOnce(Looper.java:201)
                                          	at android.os.Looper.loop(Looper.java:288)
                                          	at android.app.ActivityThread.main(ActivityThread.java:7941)
                                          	at java.lang.reflect.Method.invoke(Native Method)?
                                          	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:553)?
                                          	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)?
10:48:38.299 System.err                W  java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
10:48:38.299 System.err                W  	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:563)
10:48:38.299 System.err                W  	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
10:48:38.300 System.err                W  Caused by: java.lang.reflect.InvocationTargetException
10:48:38.300 System.err                W  	at java.lang.reflect.Method.invoke(Native Method)
10:48:38.300 System.err                W  	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:553)
10:48:38.300 System.err                W  	... 1 more
10:48:38.300 System.err                W  Caused by: java.lang.Exception: error
10:48:38.301 System.err                W  	at com.lichang.source.MainActivity.onCreate$lambda$0(MainActivity.kt:23)
10:48:38.301 System.err                W  	at com.lichang.source.MainActivity.$r8$lambda$1d06GL5SsQcwKha8s7cR5MexWzU(Unknown Source:0)
10:48:38.301 System.err                W  	at com.lichang.source.MainActivity$$ExternalSyntheticLambda0.onClick(Unknown Source:0)
10:48:38.301 System.err                W  	at android.view.View.performClick(View.java:7448)
10:48:38.302 System.err                W  	at android.view.View.performClickInternal(View.java:7421)
10:48:38.302 System.err                W  	at android.view.View.access$3700(View.java:838)
10:48:38.302 System.err                W  	at android.view.View$PerformClick.run(View.java:28870)
10:48:38.302 System.err                W  	at android.os.Handler.handleCallback(Handler.java:938)
10:48:38.302 System.err                W  	at android.os.Handler.dispatchMessage(Handler.java:99)
10:48:38.303 System.err                W  	at android.os.Looper.loopOnce(Looper.java:201)
10:48:38.303 System.err                W  	at android.os.Looper.loop(Looper.java:288)
10:48:38.303 System.err                W  	at android.app.ActivityThread.main(ActivityThread.java:7941)
10:48:38.303 System.err                W  	... 3 more
10:48:38.303 CrashHandler              E  出现了未捕获异常！！！
10:48:38.472 CrashHandler              E  Process will be killed in 2 seconds!
---------------------------- PROCESS ENDED (29787) for package com.lichang.source ----------------------------
10:48:40.473 Process                   I  Sending signal. PID: 29787 SIG: 9

记录如下：