Android编程实现获取系统内存、CPU使用率及状态栏高度的方法示例

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Field;
import java.util.List;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningTaskInfo;
import android.content.Context;
public class DeviceInfoManager {
// private static final String TAG = "DeviceInfoManager";
  private static ActivityManager mActivityManager;
  public synchronized static ActivityManager getActivityManager(Context context) {
    if (mActivityManager == null) {
      mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    }
    return mActivityManager;
  }
  /**
   * 用于获取状态栏的高度。
   *
   * @return 返回状态栏高度的像素值。
   */
  public static int getStatusBarHeight(Context context) {
    int statusBarHeight = 0;
    try {
      Class<?> c = Class.forName("com.android.internal.R$dimen");
      Object o = c.newInstance();
      Field field = c.getField("status_bar_height");
      int x = (Integer) field.get(o);
      statusBarHeight = context.getResources().getDimensionPixelSize(x);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return statusBarHeight;
  }
  /**
   * 计算已使用内存的百分比，并返回。
   *
   * @param context
   *      可传入应用程序上下文。
   * @return 已使用内存的百分比，以字符串形式返回。
   */
  public static String getUsedPercentValue(Context context) {
    long totalMemorySize = getTotalMemory();
    long availableSize = getAvailableMemory(context) / 1024;
    int percent = (int) ((totalMemorySize - availableSize) / (float) totalMemorySize * 100);
    return percent + "%";
  }
  /**
   * 获取当前可用内存，返回数据以字节为单位。
   *
   * @param context 可传入应用程序上下文。
   * @return 当前可用内存。
   */
  public static long getAvailableMemory(Context context) {
    ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();
    getActivityManager(context).getMemoryInfo(mi);
    return mi.availMem;
  }
  /**
   * 获取系统总内存,返回字节单位为KB
   * @return 系统总内存
   */
  public static long getTotalMemory() {
    long totalMemorySize = 0;
    String dir = "/proc/meminfo";
    try {
      FileReader fr = new FileReader(dir);
      BufferedReader br = new BufferedReader(fr, 2048);
      String memoryLine = br.readLine();
      String subMemoryLine = memoryLine.substring(memoryLine.indexOf("MemTotal:"));
      br.close();
      //将非数字的字符替换为空
      totalMemorySize = Integer.parseInt(subMemoryLine.replaceAll("\\D+", ""));
    } catch (IOException e) {
      e.printStackTrace();
    }
    return totalMemorySize;
  }
  /**
   * 获取顶层activity的包名
   * @param context
   * @return activity的包名
   */
  public static String getTopActivityPackageName(Context context) {
    ActivityManager activityManager = getActivityManager(context);
    List<RunningTaskInfo> runningTasks = activityManager.getRunningTasks(1);
    return runningTasks.get(0).topActivity.getPackageName();
  }
  /**
   * 获取当前进程的CPU使用率
   * @return CPU的使用率
   */
  public static float getCurProcessCpuRate()
  {
    float totalCpuTime1 = getTotalCpuTime();
    float processCpuTime1 = getAppCpuTime();
    try
    {
      Thread.sleep(360);
    }
    catch (Exception e)
    {
    }
    float totalCpuTime2 = getTotalCpuTime();
    float processCpuTime2 = getAppCpuTime();
    float cpuRate = 100 * (processCpuTime2 - processCpuTime1)
        / (totalCpuTime2 - totalCpuTime1);
    return cpuRate;
  }
  /**
   * 获取总的CPU使用率
   * @return CPU使用率
   */
  public static float getTotalCpuRate() {
    float totalCpuTime1 = getTotalCpuTime();
    float totalUsedCpuTime1 = totalCpuTime1 - sStatus.idletime;
    try {
      Thread.sleep(360);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    float totalCpuTime2 = getTotalCpuTime();
    float totalUsedCpuTime2 = totalCpuTime2 - sStatus.idletime;
    float cpuRate = 100 * (totalUsedCpuTime2 - totalUsedCpuTime1)
        / (totalCpuTime2 - totalCpuTime1);
    return cpuRate;
  }
  /**
   * 获取系统总CPU使用时间
   * @return 系统CPU总的使用时间
   */
  public static long getTotalCpuTime()
  {
    String[] cpuInfos = null;
    try
    {
      BufferedReader reader = new BufferedReader(new InputStreamReader(
          new FileInputStream("/proc/stat")), 1000);
      String load = reader.readLine();
      reader.close();
      cpuInfos = load.split(" ");
    }
    catch (IOException ex)
    {
      ex.printStackTrace();
    }
//   long totalCpu = Long.parseLong(cpuInfos[2])
//       + Long.parseLong(cpuInfos[3]) + Long.parseLong(cpuInfos[4])
//       + Long.parseLong(cpuInfos[6]) + Long.parseLong(cpuInfos[5])
//       + Long.parseLong(cpuInfos[7]) + Long.parseLong(cpuInfos[8]);
    sStatus.usertime = Long.parseLong(cpuInfos[2]);
    sStatus.nicetime = Long.parseLong(cpuInfos[3]);
    sStatus.systemtime = Long.parseLong(cpuInfos[4]);
    sStatus.idletime = Long.parseLong(cpuInfos[5]);
    sStatus.iowaittime = Long.parseLong(cpuInfos[6]);
    sStatus.irqtime = Long.parseLong(cpuInfos[7]);
    sStatus.softirqtime = Long.parseLong(cpuInfos[8]);
    return sStatus.getTotalTime();
  }
  /**
   * 获取当前进程的CPU使用时间
   * @return 当前进程的CPU使用时间
   */
  public static long getAppCpuTime()
  {
    // 获取应用占用的CPU时间
    String[] cpuInfos = null;
    try
    {
      int pid = android.os.Process.myPid();
      BufferedReader reader = new BufferedReader(new InputStreamReader(
          new FileInputStream("/proc/" + pid + "/stat")), 1000);
      String load = reader.readLine();
      reader.close();
      cpuInfos = load.split(" ");
    }
    catch (IOException ex)
    {
      ex.printStackTrace();
    }
    long appCpuTime = Long.parseLong(cpuInfos[13])
        + Long.parseLong(cpuInfos[14]) + Long.parseLong(cpuInfos[15])
        + Long.parseLong(cpuInfos[16]);
    return appCpuTime;
  }
  static Status sStatus = new Status();
  static class Status {
    public long usertime;
    public long nicetime;
    public long systemtime;
    public long idletime;
    public long iowaittime;
    public long irqtime;
    public long softirqtime;
    public long getTotalTime() {
      return (usertime + nicetime + systemtime + idletime + iowaittime
          + irqtime + softirqtime);
    }
  }
}