如何确保每次调用片段时都不会重新检索从服务器检索到的数据

Question

I am working with fragments and a navigation drawer. I have two fragments and a fragment manager to recycle them when I click on the menu items in the navigation drawer. I am also receiving data from a server in one of the fragments.

However, every time I reinitialize the fragment, the call to the server occurs again. I would like to know if there is any way that I can make sure that the server call only occurs in the beginning and when I click the refresh button.

Answer 1

I would like to know if there is any way that I can make sure that the server call only occurs in the beginning and when I click the refresh button.

Yes , when you click on the refresh button use an ClickListener to trigger the call.

If you want the call to occur only when fragment is created you can refer to the fragment life cycle. The better way is to put this call in the onCreate() method.

However if you don't want to make a call each time the fragment is created i recommend you tu use the SharedPreference to save the information that call have already been made.

exemple:

prefs = PreferenceManager.getDefaultSharedPreferences(this);
        // The seconde value of method getBoolean incates the default value if constant not found
        if (prefs.getBoolean(Constants.CALL_DONE, false)) {
            // Make call
            prefs.edit().putBoolean(Constants.CALL_DONE, true).apply();
        }