工具類

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;
}

/**
 * 用於獲取狀態欄的高度。
 *
 * @return 返回狀態欄高度的像素值。
 */
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;
}

/**
 * 計算已使用內存的百分比，並返回。
 *
 * @param context 可傳入應用程序上下文。
 * @return 已使用內存的百分比，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 + "%";
}

/**
 * 獲取當前可用內存，返回數據以字節爲單位。
 *
 * @param context 可傳入應用程序上下文。
 * @return 當前可用內存。
 */
public static long getAvailableMemory(Context context) {
    ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();
    getActivityManager(context).getMemoryInfo(mi);
    return mi.availMem;
}

/**
 * 獲取系統總內存,返回字節單位爲KB
 *
 * @return 系統總內存
 */
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();
        //將非數字的字符替換爲空
        totalMemorySize = Integer.parseInt(subMemoryLine.replaceAll("\\D+", ""));
    } catch (IOException e) {
        e.printStackTrace();
    }
    return totalMemorySize;
}

/**
 * 獲取頂層activity的包名
 *
 * @param context
 * @return activity的包名
 */
public static String getTopActivityPackageName(Context context) {
    ActivityManager activityManager = getActivityManager(context);
    List<ActivityManager.RunningTaskInfo> runningTasks = activityManager.getRunningTasks(1);
    return runningTasks.get(0).topActivity.getPackageName();
}

/**
 * 獲取當前進程的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;
}

/**
 * 獲取總的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;
}

/**
 * 獲取系統總CPU使用時間
 *
 * @return 系統CPU總的使用時間
 */
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();
}

/**
 * 獲取當前進程的CPU使用時間
 *
 * @return 當前進程的CPU使用時間
 */
public static long getAppCpuTime() {
    // 獲取應用佔用的CPU時間
    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);
    }
}

}