如何检查 Android 应用的内存使用情况_框架

原料

安卓手机（这里用华为荣耀六演示）

步骤

打开手机设置里的全部设置选项卡，再点击应用管理

选择正在运行查看当前运行的应用

安卓手机的内存使用情况在这里可见

获取 CPU 核数

Linux 中的设备都是以文件的形式存在，CPU 也不例外，因此 CPU 的文件个数就等价与核数。

Android 的 CPU 设备文件位于/sys/devices/system/cpu/目录，文件名的的格式为cpu\d+。

root@generic_x86_64:/sys/devices/system/cpu # ls cpu0 cpufreq

cpuidle

kernel_max

modalias

offline

online

possible

power

present

uevent

统计一下文件个数便可以获得 CPU 核数。

public static int getNumberOfCPUCores() {

if (BuildVERSIONSDK_INT <= BuildVERSION_CODESGINGERBREAD_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 = pathnamegetName();

//regex is slow, so checking char by char

if (pathstartsWith("cpu")) {

for (int i = 3; i < pathlength(); i++) {

if (pathcharAt(i) < '0' || pathcharAt(i) > '9') {

return false;

}

return true;

}

return false;

}

};

获取时钟频率

获取时钟频率需要读取系统文件 -/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq或者/proc/cpuinfo。

Android 模拟器中并没有cpuinfo_max_freq文件，因此只能读取/proc/cpuinfo。

/proc/cpuinfo包含了很多 cpu 数据。

processor : 0

vendor_id : GenuineIntel

cpu family : 6

model : 70

model name : Intel(R) Core(TM) i7-4770HQ CPU @ 220GHz

stepping : 1

cpu MHz : 0000

cache size : 1024 KB

fdiv_bug : no

hlt_bug : no

f00f_bug : no

coma_bug : no

fpu : yes

fpu_exception : yes

cpuid level : 4

wp : yes

代码如下：

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 (cpuInfoMaxFreqFileexists()) {

byte[] buffer = new byte[128];

FileInputStream stream = new FileInputStream(cpuInfoMaxFreqFile);

try {

streamread(buffer);

int endIndex = 0;

//Trim the first number out of the byte buffer

while (buffer[endIndex] >= '0' && buffer[endIndex] <= '9'

&& endIndex < bufferlength) endIndex++;

String str = new String(buffer, 0, endIndex);

Integer freqBound = IntegerparseInt(str);

if (freqBound > maxFreq) maxFreq = freqBound;

} catch (NumberFormatException e) {

//Fall through and use /proc/cpuinfo

} finally {

streamclose();

}

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 {

streamclose();

}

} catch (IOException e) {

maxFreq = DEVICEINFO_UNKNOWN; //Fall through and return unknown

}

return maxFreq;

}

获取内存大小

如果 SDK 版本大于等于JELLY_BEAN，可以通过ActivityManager来获取内从大小。

ActivityManagerMemoryInfo memInfo = new ActivityManagerMemoryInfo();

ActivityManager am = (ActivityManager) cgetSystemService(ContextACTIVITY_SERVICE);

amgetMemoryInfo(memInfo);

如果版本低于JELLY_BEAN，则只能读取系统文件了。

FileInputStream stream = new FileInputStream("/proc/meminfo");

totalMem = parseFileForValue("MemTotal", stream);

完整代码如下：

@TargetApi(BuildVERSION_CODESJELLY_BEAN)

public static long getTotalMemory(Context c) {

// memInfototalMem not supported in pre-Jelly Bean APIs

if (BuildVERSIONSDK_INT >= BuildVERSION_CODESJELLY_BEAN) {

ActivityManagerMemoryInfo memInfo = new ActivityManagerMemoryInfo();

ActivityManager am = (ActivityManager) cgetSystemService(ContextACTIVITY_SERVICE);

amgetMemoryInfo(memInfo);

if (memInfo != null) {

return memInfototalMem;

} else {

return DEVICEINFO_UNKNOWN;

}

} else {

long totalMem = DEVICEINFO_UNKNOWN;

try {

FileInputStream stream = new FileInputStream("/proc/meminfo");

try {

totalMem = parseFileForValue("MemTotal", stream);

totalMem = 1024;

} finally {

streamclose();

}

} catch (IOException e) {

}

return totalMem;

}

我们开发的android 应用程序,占用内存太多，都在24M-32M 之间峰值的时候达到了 64M，

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