iOS core note--ios notification mechanism

1, IOS notification mechanism: 1-1, iOS notification publisher, Notification Center, the relationship between listeners:

as shown in the following:

2, notice (nsnotification) Introduction:

3, Notification Center (nsnotificationcenter) 3-1, each application has only one notification hub object (Singleton object):

4, Release Notice: 4-1, the object at a time when they need to use the notification class (Nsnotification) to notify the Notification Center to help publish the notification:

• 1, can be in the object a need to use a notification location, direct Notification Center to help send a series of information in the notification through the Notification Center provides a method to create a notification and send out simultaneously:

  sample program :

       1.-(void) postnote{
   2.    MARK:-Send notification 
   3.                        [[Nsnotificationcenter Defaultcenter] postnotificationname:@ "HF" Object:self userinfo:@{
   4.     @ "name": @ "He Hua", 
   5. @ "Birthday": @ "1994-01-19" 
   6. }]; 
   7.} 
    

   

• 2, first create the notification object, set the notification information when it is created, and then let the notification Center help send:

  sample program :

    1.-(void) postnote2{
   2. 1.    Create a notification 
   3.                        Nsnotification *note = [nsnotification notificationwithname:@ "HF2" Object:self userinfo:@{
   4.                         @ "name": @ "He Hua 2", 
   5. @ "Birthday": @ "01-19" 
   6. }];    
   7.//2. Notification Center to help send 
   8. [[Nsnotificationcenter Defaultcenter] postnotification:note]; 
   9.} 
    

   

• 3, common methods for posting notifications:

5, monitoring notification: 5-1, the listener only after the Notification Center registration monitoring notification, to receive notification after the announcement, and listener registration monitoring must be in the notification before the release; 5-2, listener Registration Monitoring notification common way:

• Way One:
  
• Way two:

6, Cancellation: 6-1, the listener must be written off before destroying the notification, otherwise, will cause the problem of wild pointers; 6-2. How the listener logs off the notifications it listens to:

7, keyboard notification: 7-1, common keyboard notification type:

7-2, keyboard notification commonly used additional information:

8, the common keyboard notification: 8-1, the keyboard will be displayed:

8-2. The keyboard will be hidden:

8-3, the keyboard frame will be changed:

9, iOS device class notification: 9-1, UIDEVICE class notification:

10, Comparison notice and agent: 10-1, Agent:

• 1, the role of agent design mode:

• 1.A object listens to some behavior of B object, a becomes agent of B;
  
• 2.B objects want to tell a object something, a becomes a proxy for B.

• 2, the agent Design Model summary:

• If you want to listen to other people's behavior, then you will be the agent of others;
  
• If you want to tell someone something, then let someone else be your agent.

• 3, the agent design mode development steps:

• 1. To prepare an agreement (the format of the agreement name: control name + Delegate), in the agreement to declare some proxy methods (the general Agent method is @optional);
  
• 2. Declare a proxy property: @property (nonatomic, weak) id< Agent agreement > delegate;
  
• 3. When some internal behavior occurs, call the agent corresponding Agent method, notify the agent what happened inside;
  
• 4. Set Proxy: Xxx.delegate = YYY;
  
• The 5.yyy object adheres to the protocol and implements the proxy method.

• 4, the difference between agent and notice:

• Agent: An object can only tell the other 1 objects what happened;

• Notification: An object can tell what happened to n objects.

10-2, the choice of notification and agent:

iOS core note--ios notification mechanism