将样式应用于选中的单选按钮的父级(Applying styling to a checked radio button's parent)

 有很多方法可以处理一次性登录，这很大程度上取决于如何在服务器端实现体系结构以使其工作。 由于安全原因，通常Login API closely coupled 。 让我举一个例子，我的意思是closely coupled 。 
 
 当您想要Login Mobile App工作一次，并且下次用户打开Mobile app您不希望再次提示用户使用SignIn屏幕。 当然，您不希望将移动应用上的Username和Password等机密信息Username为持久数据，因为它可以从Android设备轻松获取。 那你干什么。 
 
 让我们假设您传递了具有Android Device唯一的deviceID登录凭据。 如下所示的东西。 以下是发送到LoginAPI的JSON数据 
 
{
    "username": "example@example.com",
    "password": "it's not a secret",
    "deviceId": "123456789"
}
 
 现在，由于您不想保存Login凭据，服务器将生成随机字母数字String ，每次您登录移动应用程序时都会将其传递给您。 
 
{
    "Success": true,
    "SuccessMessage": "credentials are correct, really!",
    "ErrorMessage": null,
    "Date": "dd/mm/yyyy",
    "token": "1eghe4qha23aehraeh456789" // now this is a nasty String
}
 
 您现在可以将date和token作为持久数据保存在Mobile App中。 因此，下次用户打开应用程序时，您可以让用户绕过SignIn屏幕，在后台，您可以通过将用户令牌ID发送到服务器来检查用户令牌ID是否正确，如下所示。 您可以选择SharedPreferences或创建文件并将其保存在那里 
 
{
    "API_TYPE": "login",
    "deviceId": "123456789",
    "token": "1eghe4qha23aehraeh456789"
}
 
 服务器可以针对deviceID检查此令牌ID，以检查这是否是设备的正确令牌并进行响应。 
 
 您可能会问为什么我们再次检查token ，因为这是由服务器首先发出的，表明凭据是正确的。 我同意你有一个观点，假设它是一个故障安全条件，如果用户从网站更改密码或导致更改服务器上的令牌以供该用户更改的东西，如果服务器拒绝提供的令牌你只是要求用户再次登录。 
 
 这将确保用户在任何给定的时间点仅登录到一个Android Device 。 

There are many ways to deal with one time login, it depends a lot on how the architecture is implemented on server side to make it work. Usually Login API are closely coupled for security reason. let me example what I mean by closely coupled. 
 
As you want to Login in to Mobile App work once and the next time user opens the Mobile app you don't want to prompt user with SignIn screen again. and surely you don't want to save the confidential information like Username and Password on Mobile app as persistent data, as it can be fetched easily from android device. so what you do. 
 
Lets assume you pass login credentials with a deviceID unique to the Android Device. Something like shown below. following is the JSON data sent to the LoginAPI
 
{
    "username": "example@example.com",
    "password": "it's not a secret",
    "deviceId": "123456789"
}
 
Now as you don't want to save the Login credentials, server will generate a random alpha numeric String pass it to you in response every time you login to the Mobile App.
 
{
    "Success": true,
    "SuccessMessage": "credentials are correct, really!",
    "ErrorMessage": null,
    "Date": "dd/mm/yyyy",
    "token": "1eghe4qha23aehraeh456789" // now this is a nasty String
}
 
you may now save the date and the token in Mobile App as persistent data. So next time your user opens the app you may let user bypass the SignIn screen, and in background you can check if users token id is correct by sending that to the server, something like this. you may choose SharedPreferences or create a file and save it there
 
{
    "API_TYPE": "login",
    "deviceId": "123456789",
    "token": "1eghe4qha23aehraeh456789"
}
 
Server may check this token id against the deviceID to check if this was the correct token for the device and respond.
 
You may ask why are we checking the token again as this was sent by the server in first place stating the credentials were correct. I agree you do have a point, lets say it is a fail safe condition, if the user changes the password from the website or something which causes to change the token on server for that user to change, if the server denies the token provided by you just ask the user to login again.
 
This will make sure that a user is logged in to only one Android Device at any given point of time.