得到当前进程数 得到系统总共内存，使用了多少内存

package com.itheima.mobileguard.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.util.List;

import android.R.integer;
import android.app.ActivityManager;
import android.app.ActivityManager.MemoryInfo;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.app.ActivityManager.RunningServiceInfo;
import android.content.Context;

public class SystemInfoUtils {
    /**
     * 判断一个服务是否处于运行状态
     * 
     * @param context
     *            上下文
     * @return
     */
    public static boolean isServiceRunning(Context context, String className) {
        ActivityManager am = (ActivityManager) context
                .getSystemService(Context.ACTIVITY_SERVICE);
        List<RunningServiceInfo> infos = am.getRunningServices(200);
        for (RunningServiceInfo info : infos) {
            String serviceClassName = info.service.getClassName();
            if (className.equals(serviceClassName)) {
                return true;
            }
        }
        return false;
    }

    /**
     * 返回进程的总个数
     * 
     * @param context
     * @return
     */
    public static int getProcessCount(Context context) {
        // 得到进程管理者
        ActivityManager activityManager = (ActivityManager) context
                .getSystemService(context.ACTIVITY_SERVICE);
        // 获取到当前手机上面所有运行的进程
        List<RunningAppProcessInfo> runningAppProcesses = activityManager
                .getRunningAppProcesses();

        // 获取手机上面一共有多少个进程
        return runningAppProcesses.size();
    }

    public static long getAvailMem(Context context) {
        // 得到进程管理者
        ActivityManager activityManager = (ActivityManager) context
                .getSystemService(context.ACTIVITY_SERVICE);
        MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();

        // 获取到内存的基本信息
        activityManager.getMemoryInfo(memoryInfo);
        // 获取到剩余内存
        return memoryInfo.availMem;
    }

    public static long getTotalMem(Context context) {
        // 获取到总内存
        /*
         * 这个地方不能直接跑到低版本的手机上面 MemTotal: 344740 kB "/proc/meminfo"
         */
        try {
            // /proc/meminfo 配置文件的路径
            FileInputStream fis = new FileInputStream(new File("/proc/meminfo"));

            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    fis));

            String readLine = reader.readLine();

            StringBuffer sb = new StringBuffer();

            for (char c : readLine.toCharArray()) {
                if (c >= '0' && c <= '9') {
                    sb.append(c);
                }
            }
            return Long.parseLong(sb.toString()) * 1024;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return 0;

    }

}