Simple summary of various types of delay triggering

The Performselector method is typically used to delay operations in a specified method, or to pass parameters in a specified method. However, the Performselector method is lack of security in the delay operation, in the case of high security requirements, can call Dispatch_after to achieve a single time delay call.

(1) Dispatch_after achieve 3 second delay:

1 3*nsec_per_sec); 2     Dispatch_after (Time, Dispatch_get_main_queue (), ^{3        [self dismisspage]; 4     }); 5-(void) dismisspage{6     NSLog (@ " three seconds away ");     [Adview Removefromsuperview]; 8}

(2) Some simple summaries of the Performselector method:

Note: The default mode for Performselector is: Nsdefaultrunloopmode. Runloop is a message processing mechanism in which a thread can perform only one task at a time, and the thread exits after execution completes. If we need a mechanism that allows threads to handle events at any time without exiting, Runloop is the mechanism for handling such tasks.

1     //1. Normal method Invocation2 [Self performselector: @selector (dismisspage)];3     //2. Method invocation of the parameter transfer4NSString *str =@"mo Xue";5    //[Self performselector: @selector (dismisspage:) withobject:str];6     //3. Delay parameter7[Self performselector: @selector (dismisspage:) withobject:str Afterdelay:3.0];8     //4. Execute the specified method on the main thread, using the default mode (Nsdefaultrunloopmode). 9     //The default mode refers to: The method in the main thread is queued, is a loop queue, and is executed in a loop. Ten     //Wait: The Aselector method to execute is executed immediately.  One     //If set to Yes: Wait for the current thread to finish executing, the main thread will not execute the Aselector method; A     //set to No: Do not wait for the current thread to finish executing the Aselector method on the main thread.  -     //if the current thread is the main path, the Aselector method executes immediately.  - [Self performselectoronmainthread: @selector (dismisspage:) withobject:str Waituntildone:yes]; the  -  --(void) Dismisspage: (NSString *) ad{ -NSLog (@"%@", AD); + [Adview Removefromsuperview]; -      } +-(void) dismisspage{ ANSLog (@"three seconds to disappear ."); at [Adview Removefromsuperview]; -}

(3) Nstimer implementation delay:

1     //the first method of initializing the Nstimer:2Nstimer *timer = [Nstimer scheduledtimerwithtimeinterval:3target:self selector: @selector (dismisspage) Userinfo:nil Repeats:nil];3     //the second method of initializing the Nstimer:4Nstimer *timer = [Nstimer timerwithtimeinterval:3.0target:self selector: @selector (dismisspage) Userinfo:nil Repeats:no];5 [[Nsrunloop Currentrunloop]addtimer:timer Formode:nsdefaultrunloopmode];6 7-(void) dismisspage{8NSLog (@"three seconds to disappear .");9 [Adview Removefromsuperview];Ten}

Trigger or start of Nstimer:

You can use the-(void) Fire method to trigger the timer immediately;

Stop of Nstimer:

-(void) invalidate; Remove the timer from the Runloop.

Simple summary of various types of delay triggering