Android获取系统的内存使用率

1，获取系统当前的可用内存

        private static long getAvailableMemory(Context context) {
		ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();
		getActivityManager(context).getMemoryInfo(mi);
		return mi.availMem;
	}

2，计算内存使用率

        public static String getUsedPercentValue(Context context) {
		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();
			long totalMemorySize = Integer.parseInt(subMemoryLine.replaceAll("\\D+", ""));
			long availableSize = getAvailableMemory(context) / 1024;
			int percent = (int) ((totalMemorySize - availableSize) / (float) totalMemorySize * 100);
			return percent + "%";
		} catch (IOException e) {
			e.printStackTrace();
		}
		return "none";
	}