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目标

监控app的CPU使用率.

方案

1. 对于8.0以上版本,执行top命令,从结果里直接提取出当前app占用CPU比例.
2. 对于8.0以下版本,通过读取“/proc/stat”和“/proc/App进程ID/stat”两个文件,计算出app进程占用的CPU比例.

• 完整代码:

package com.mb.roamdriver.myapm.cpuimport android.os.Buildimport android.text.TextUtilsimport java.io.BufferedReaderimport java.io.IOExceptionimport java.io.InputStreamReaderimport java.io.RandomAccessFileobject CpuUtil {
       private var mProcStatFile: RandomAccessFile? = null    private var mAppStatFile: RandomAccessFile? = null    private var mLastCpuTime: Long? = null    private var mLastAppCpuTime: Long? = null    /**     * 获取cpu使用率     */    fun getCpuUsage(): Float {
           return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
               getCpuUsageForHigherVersion()        } else {
               getCpuUsageForLowerVersion()        }    }    /**     * 安卓8.0以上版本获取cpu使用率     */    private fun getCpuUsageForHigherVersion(): Float {
           var process: Process? = null        try {
               process = Runtime.getRuntime().exec("top -n 1")            val reader = BufferedReader(InputStreamReader(process.inputStream))            var line: String            var cpuIndex = -1            while (reader.readLine().also {
    line = it } != null) {
                   line = line.trim {
    it <= ' ' }                if (TextUtils.isEmpty(line)) {
                       continue                }                val tempIndex = getCPUIndex(line)                if (tempIndex != -1) {
                       cpuIndex = tempIndex                    continue                }                if (line.startsWith(android.os.Process.myPid().toString())) {
                       if (cpuIndex == -1) {
                           continue                    }                    val param = line.split("\\s+".toRegex()).toTypedArray()                    if (param.size <= cpuIndex) {
                           continue                    }                    var cpu = param[cpuIndex]                    if (cpu.endsWith("%")) {
                           cpu = cpu.substring(0, cpu.lastIndexOf("%"))                    }                    return cpu.toFloat() / Runtime.getRuntime().availableProcessors()                }            }        } catch (e: IOException) {
               e.printStackTrace()        } finally {
               process?.destroy()        }        return 0F    }    /**     * 安卓8.0以下版本获取cpu使用率     */    private fun getCpuUsageForLowerVersion(): Float {
           val cpuTime: Long        val appTime: Long        var value = 0.0f        try {
               if (mProcStatFile == null || mAppStatFile == null) {
                   mProcStatFile = RandomAccessFile("/proc/stat", "r")                mAppStatFile = RandomAccessFile("/proc/" + android.os.Process.myPid() + "/stat", "r")            } else {
                   mProcStatFile!!.seek(0L)                mAppStatFile!!.seek(0L)            }            val procStatString = mProcStatFile!!.readLine()            val appStatString = mAppStatFile!!.readLine()            val procStats = procStatString.split(" ".toRegex()).toTypedArray()            val appStats = appStatString.split(" ".toRegex()).toTypedArray()            cpuTime = procStats[2].toLong() + procStats[3].toLong() + procStats[4].toLong() + procStats[5].toLong() + procStats[6].toLong() + procStats[7].toLong() + procStats[8].toLong()            appTime = appStats[13].toLong() + appStats[14].toLong()            if (mLastCpuTime == null && mLastAppCpuTime == null) {
                   mLastCpuTime = cpuTime                mLastAppCpuTime = appTime                return value            }            value = (appTime - mLastAppCpuTime!!).toFloat() / (cpuTime - mLastCpuTime!!).toFloat() * 100f            mLastCpuTime = cpuTime            mLastAppCpuTime = appTime        } catch (e: Exception) {
               e.printStackTrace()        }        return value    }    private fun getCPUIndex(line: String): Int {
           if (line.contains("CPU")) {
               val titles = line.split("\\s+".toRegex()).toTypedArray()            for (i in titles.indices) {
                   if (titles[i].contains("CPU")) {
                       return i                }            }        }        return -1    }}

• 调用样例:

Log.d("MyApm-CPU使用率", CpuUtil.getCpuUsage().toString())

完整源代码

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