做另一面的自己

Chromium 提供判断低端机方法

发表于 | 分类于 | 
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public static boolean isLowEndDevice() {
        if(sLowEndDevice == null) {
            sLowEndDevice = Boolean.valueOf(detectLowEndDevice());
        }
        return sLowEndDevice.booleanValue();
    }

实现：

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private static boolean detectLowEndDevice() {
        assert CommandLine.isInitialized();
        if(CommandLine.getInstance().hasSwitch("enable-low-end-device-mode")) {
            return true;
        } else if(CommandLine.getInstance().hasSwitch("disable-low-end-device-mode")) {
            return false;
        } else {
            int ramSizeKB = amountOfPhysicalMemoryKB();
            return ramSizeKB > 0 && ramSizeKB / 1024 < 512;
        }
    }

读取 /proc/meminfo 目录正则匹配出物理内存地址，具体代码如下：

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private static int amountOfPhysicalMemoryKB() {
        Pattern pattern = Pattern.compile("^MemTotal:\\s+([0-9]+) kB$");
        ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
        try {
            FileReader e = new FileReader("/proc/meminfo");
            try {
                BufferedReader reader = new BufferedReader(e);
                try {
                    while(true) {
                        String line = reader.readLine();
                        if(line == null) {
                            Log.w("SysUtils", "/proc/meminfo lacks a MemTotal entry?");
                            break;
                        }
                        Matcher m = pattern.matcher(line);
                        if(m.find()) {
                            int totalMemoryKB = Integer.parseInt(m.group(1));
                            if(totalMemoryKB > 1024) {
                                int var7 = totalMemoryKB;
                                return var7;
                            }
                            Log.w("SysUtils", "Invalid /proc/meminfo total size in kB: " + m.group(1));
                            break;
                        }
                    }
                } finally {
                    reader.close();
                }
            } finally {
                e.close();
            }
        } catch (Exception var25) {
            Log.w("SysUtils", "Cannot get total physical size from /proc/meminfo", var25);
        } finally {
            StrictMode.setThreadPolicy(oldPolicy);
        }
        return 0;
    }