android 得到cpu当前运行频率

有时候，我们希望得到cpu的频率，以决定是否需要对cpu的频率进行调整。在google上搜索了一下后，得到了我想要的答案。修改并运行了一下，是可以得到cpu的频率的。它的原理实质是从文件中读取频率的。

原本这段代码是读取最大频率的，只需要把 “/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq“改成

“/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq”就可以得到当前频率了。

//package org.anddev.andengine.util;import java.io.IOException;import java.io.InputStream;import java.lang.reflect.Method;import java.util.Scanner;import java.util.regex.MatchResult;import android.content.Context;import android.content.pm.PackageInfo;import android.content.pm.PackageManager;import android.content.pm.PackageManager.NameNotFoundException;import android.os.Build;/** * (c) 2010 Nicolas Gramlich  * (c) 2011 Zynga Inc. *  * @author Nicolas Gramlich * @since 15:50:31 - 14.07.2010 */class SystemUtils {  private static final String BOGOMIPS_PATTERN = "BogoMIPS[\\s]*:[\\s]*(\\d+\\.\\d+)[\\s]*\n";  private static final String MEMTOTAL_PATTERN = "MemTotal[\\s]*:[\\s]*(\\d+)[\\s]*kB\n";  private static final String MEMFREE_PATTERN = "MemFree[\\s]*:[\\s]*(\\d+)[\\s]*kB\n";  /**   * @return in kiloHertz.   * @throws SystemUtilsException   */  public static int getCPUFrequencyMax() throws Exception {    return SystemUtils.      readSystemFileAsInt("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq");  }  private static int readSystemFileAsInt(final String pSystemFile) throws Exception {    InputStream in = null;    try {      final Process process = new ProcessBuilder(new String[] {     "/system/bin/cat", pSystemFile }).start();      in = process.getInputStream();      final String content = readFully(in);      return Integer.parseInt(content);    } catch (final Exception e) {      throw new Exception(e);    }   }  public static final String readFully(final InputStream pInputStream) throws IOException {    final StringBuilder sb = new StringBuilder();    final Scanner sc = new Scanner(pInputStream);    while(sc.hasNextLine()) {      sb.append(sc.nextLine());    }    return sb.toString();  }  private static MatchResult matchSystemFile(final String pSystemFile, final String pPattern, final int pHorizon) throws Exception {    InputStream in = null;    try {      final Process process = new ProcessBuilder(new String[] { "/system/bin/cat", pSystemFile }).start();      in = process.getInputStream();      final Scanner scanner = new Scanner(in);      final boolean matchFound = scanner.findWithinHorizon(pPattern, pHorizon) != null;      if(matchFound) {        return scanner.match();      } else {        throw new Exception();      }    } catch (final IOException e) {      throw new Exception(e);    }         }}