Creating Preferences in a NewtApp-based Application

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This document was exported on 7/23/97.

Creating Preferences in a NewtApp-based Application (1/31/96)

Q: How do I create and use my own preferences slip in a NewtApp-based application?

A: In your application's base view create a slot called prefsView and place a reference to the template for your preferences slip there (probably using the NTK GetLayout function.) When the user selects "Prefs" from the Info button in your application, the NewtApp framework will create and open a view based on the template in the prefsView slot.

When your preferences view opens, a reference to your application's base view is stored in a slot called theApp in the preferences view. Use this reference to call the application's GetAppPreferences method. This method will return a frame containing your application's preferences. GetAppPreferences is a method provided by NewtApp and should not be overidden.

When adding slots to the preferences frame, you must either append your developer signature to the name of the preference (for example, '|Pref1:SIG|) or create a slot in the preferences frame using your developer signature and save all preferences in that frame. This will guarantee that you don't overwrite slots used by the NewtApp framework.

Here is an example of how to get the preferences frame and add your data:
        preferencesSlip.viewSetupFormScript := func() 
    begin
        prefs := theApp:GetAppPreferences();
        if NOT HasSlot(prefs, kAppSymbol) then
            prefs.(kAppSymbol) := {myPref1: nil, myPref2: nil};
    end;

To save the preferences, call the application's SaveAppState method:
    preferencesSlip.viewQuitScript := func()
        theApp:SaveAppState(); // save prefs


NewtApp currently provides one built-in preference for where to save new items. In the preferences frame there will be a slot called internalStore. Setting this slot to true will force the NewtApp framework to save all new items on the internal store.