Day-13

Question 1

Parse GeoPoint

Answer 1

Parse is setup to allow you to easily incorporate locations into your data set

Question 2

PFQuery

Answer 2

PFQuery has a restriction called whereKey:nearGeoPoint: that lets you query on a location based field

Using a nearGeoPoint constraint will limit results within 100 miles

Question 3

PFSubclassing

Answer 3

subclassing PFObject makes it feel more like regular model objects and makes it so we can work with regular properties, instead of the subscripting

Question 4

To use (.) notation instead of Strings @"unsafeString"
and create PFObject

Answer 4

• Make a class that subclasses PFObject
• Make the class conform to the PFSubclassing protocol
• Implement the class method parseClassName on your class
• Import PFObject.h in your .m file
• Call [YourClass registerSubclass] in your app delegate before you call setApplicationID:clientKey:

Question 5

Map Overlays

Answer 5

Overlays offer a way to layer content over an arbitrary region of the map

An overlay object, which is an instance of a class that conforms to the MKOverlay protocol. This object manages the data points of the overlay

An overlay renderer, which is a subclass of MKOverlayRenderer that does the actual drawing of the overlay onto the map

Question 6

_ _ weak & _ _ strong

Make a controller weak then Strong in a block

Answer 6

Avoiding the retain cycle.
We only do this in a block that references self.

_ _weak typeof(self) bruce = self; (make the current controller weak because it has an strong reference originally)

//The block for completion that requires a strong reference to the self(controller)
    newReminderViewController.completion = ^(MKCircle *circle){
   //make the controller strong again
     _ _strong typeof (bruce) hulk = bruce;
 };

Question 7

Broadcast Pattern & Notification Center

Answer 7

The notification pattern is used to pass around information related to the occurrence of events

Each program, or app, has a default notification center you can access with [NSNotificationCenter defaultCenter]. Almost always you will be posting notifications to this center

A notification center delivers notifications synchronously. To send them asynchronously you will have to use a notification queue

1) addObserver:selector:name:object

deallocat it with:
2) removeObserver

Question 8

Dangling pointer

Answer 8

Pointer to deallocated object that doesn’t live in the memory