Module 13: Creating a Facebook Clone
Transcript
it’s now time to map the push support into the client side to do that we need to implement the push callback interface in the main class of our app we can only implement push callback in the main class nowhere else register push should be invoked with every launch to refresh the push key as it might change we use call serially to defer this so we don’t block the start method the push method is invoked with the text of the push in that case we call the refresh method to update the ui we’ll discuss that method soon the device id isn’t the push key it’s the os native push value normally you would have no need for it as it’s here for compatibility only the push key value is only guaranteed once this callback is invoked if the push key changed since the last time we update the push key in the server we’ll cover this method soon there isn’t much we can do in the case of an error so right now i only log it in some cases you can show a ui notification but make sure not to do it from this method as it’s invoked early in the app launch cycle and that might impact the ui in odd ways just store the error details and show a notice later on next we need to cover the server api changes and refresh method we’ll start with the former in the sign up or login method of the server api we need to invoke register push after the successful login this is important for the first time the user logs in to the app next we need to map the update push key method this is just a simple call with one argument we return a boolean value to indicate that the call worked that’s it ui controller needs a bit of work too first we need to add a field for the main form instance this will allow us to refresh the main form as notifications come in the method is now updated this method is now updated with the new main field so we can refresh the ui refresh delegates into the main form instance it’s possible that the push method is invoked before loading completed so main would be null in that case this isn’t a problem since main would be created with fresh data anyway again with mainform we need to take fields that were in the constructor before and move them to the class level so we can refresh them once we went through that with the refresh method is easy if we are currently viewing the news feed and we aren’t minimized a refresh might create a bad user experience if we are minimized or in a different tab we can refresh the ui immediately this refresh method is from infinite container the same logic applies to the notification code this method shows a toast bar offering the user a refresh if he taps the toast bar we use this to prompt the user instead of refreshing automatically with that push should work and refresh when applicable