Android 源码 优雅的代码（持续更新）

翻阅不少源码 下面讲述下 一些令人眼前一亮的代码

关于mac地址校验

/**
     * Validate a String Bluetooth address, such as "00:43:A8:23:10:F0"
     * <p>Alphabetic characters must be uppercase to be valid.
     *
     * @param address Bluetooth address as string
     * @return true if the address is valid, false otherwise
     */
    public static boolean checkBluetoothAddress(String address) {
        if (address == null || address.length() != ADDRESS_LENGTH) {
            return false;
        }
        for (int i = 0; i < ADDRESS_LENGTH; i++) {
            char c = address.charAt(i);
            switch (i % 3) {
            case 0:
            case 1:
                if ((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F')) {
                    // hex character, OK
                    break;
                }
                return false;
            case 2:
                if (c == ':') {
                    break;  // OK
                }
                return false;
            }
        }
        return true;
    }