Android获取设备CPU核数、时钟频率以及内存大小的方法

root@generic_x86_64:/sys/devices/system/cpu # ls
cpu0
cpufreq
cpuidle
kernel_max
modalias
offline
online
possible
power
present
uevent

public static int getNumberOfCPUCores() {
 if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD_MR1) {
 // Gingerbread doesn't support giving a single application access to both cores, but a
 // handful of devices (Atrix 4G and Droid X2 for example) were released with a dual-core
 // chipset and Gingerbread; that can let an app in the background run without impacting
 // the foreground application. But for our purposes, it makes them single core.
 return 1;
 }
 int cores;
 try {
 cores = new File("/sys/devices/system/cpu/").listFiles(CPU_FILTER).length;
 } catch (SecurityException e) {
 cores = DEVICEINFO_UNKNOWN;
 } catch (NullPointerException e) {
 cores = DEVICEINFO_UNKNOWN;
 }
 return cores;
}
private static final FileFilter CPU_FILTER = new FileFilter() {
 @Override
 public boolean accept(File pathname) {
 String path = pathname.getName();
 //regex is slow, so checking char by char.
 if (path.startsWith("cpu")) {
  for (int i = 3; i < path.length(); i++) {
  if (path.charAt(i) < '0' || path.charAt(i) > '9') {
   return false;
  }
  }
  return true;
 }
 return false;
 }
};

public static int getCPUMaxFreqKHz() {
 int maxFreq = DEVICEINFO_UNKNOWN;
 try {
 for (int i = 0; i < getNumberOfCPUCores(); i++) {
  String filename =
   "/sys/devices/system/cpu/cpu" + i + "/cpufreq/cpuinfo_max_freq";
  File cpuInfoMaxFreqFile = new File(filename);
  if (cpuInfoMaxFreqFile.exists()) {
  byte[] buffer = new byte[128];
  FileInputStream stream = new FileInputStream(cpuInfoMaxFreqFile);
  try {
   stream.read(buffer);
   int endIndex = 0;
   //Trim the first number out of the byte buffer.
   while (buffer[endIndex] >= '0' && buffer[endIndex] <= '9'
    && endIndex < buffer.length) endIndex++;
   String str = new String(buffer, 0, endIndex);
   Integer freqBound = Integer.parseInt(str);
   if (freqBound > maxFreq) maxFreq = freqBound;
  } catch (NumberFormatException e) {
   //Fall through and use /proc/cpuinfo.
  } finally {
   stream.close();
  }
  }
 }
 if (maxFreq == DEVICEINFO_UNKNOWN) {
  FileInputStream stream = new FileInputStream("/proc/cpuinfo");
  try {
  int freqBound = parseFileForValue("cpu MHz", stream);
  freqBound *= 1000; //MHz -> kHz
  if (freqBound > maxFreq) maxFreq = freqBound;
  } finally {
  stream.close();
  }
 }
 } catch (IOException e) {
 maxFreq = DEVICEINFO_UNKNOWN; //Fall through and return unknown.
 }
 return maxFreq;
}

ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo();
ActivityManager am = (ActivityManager) c.getSystemService(Context.ACTIVITY_SERVICE);
am.getMemoryInfo(memInfo);

FileInputStream stream = new FileInputStream("/proc/meminfo");
totalMem = parseFileForValue("MemTotal", stream);

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public static long getTotalMemory(Context c) {
 // memInfo.totalMem not supported in pre-Jelly Bean APIs.
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
 ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo();
 ActivityManager am = (ActivityManager) c.getSystemService(Context.ACTIVITY_SERVICE);
 am.getMemoryInfo(memInfo);
 if (memInfo != null) {
  return memInfo.totalMem;
 } else {
  return DEVICEINFO_UNKNOWN;
 }
 } else {
 long totalMem = DEVICEINFO_UNKNOWN;
 try {
  FileInputStream stream = new FileInputStream("/proc/meminfo");
  try {
  totalMem = parseFileForValue("MemTotal", stream);
  totalMem *= 1024;
  } finally {
  stream.close();
  }
 } catch (IOException e) {
 }
 return totalMem;
 }
}