判断手机是否root，不弹出root请求框

/** 判断手机是否root，不弹出root请求框 */
    public static boolean isRoot() {
        String binPath = "/system/bin/su";
        String xBinPath = "/system/xbin/su";
        if (new File(binPath).exists() && isExecutable(binPath))
            return true;
        if (new File(xBinPath).exists() && isExecutable(xBinPath))
            return true;
        return false;
    }
    private static boolean isExecutable(String filePath) {
        Process p = null;
        try {
            p = Runtime.getRuntime().exec("ls -l " + filePath);
            // 获取返回内容
            BufferedReader in = new BufferedReader(new InputStreamReader(
                    p.getInputStream()));
            String str = in.readLine();
            if (str != null && str.length() >= 4) {
                char flag = str.charAt(3);
                if (flag == 's' || flag == 'x')
                    return true;
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (p != null) {
                p.destroy();
            }
        }
        return false;
    }