Commonly used time-lapse execution

1, Performselector once custom delay task, will not get stuck in the current thread

// call the self's Run method after 2 seconds [Self performselector: @selector (Run) Withobject:nil Afterdelay:2.0];

2. Using the GCD function

// in this method, the incoming queue is used to determine which thread the block executes   in. // If the host column is passed in, the block is  called on the main thread // If a global queue is passed in, the block is called  in the child thread Dispatch_after (Dispatch_time (Dispatch_time_now, (int64_t) (3.0 * nsec_per_sec)), Dispatch_get_global_queue (00//  Here the incoming global queue executes the block in the child thread, and if the incoming host column executes the block      in the main thread NSLog (@ "3 seconds after execution  %@", [Nsthread CurrentThread]);  });

3. Using Nstimer

[Nstimer scheduledtimerwithtimeinterval:2.0  target:self selector: @selector (Test) Userinfo:nil repeats: NO]; -(void) test{    NSLog (@ "----BEGIN-----");    [Nsthread sleepfortimeinterval: 3 // it will snap the thread    NSLog (@ "----End-----");}

4, [Nsthread Sleepfortimeinterval:3] will be stuck thread, not

-(void) dely1{  //  1, delay execution do not use Sleepfortimeinterval (it will snap thread)  NSLog (@ "  ----BEGIN-----");  [Nsthread sleepfortimeinterval: 3 ];  NSLog (@ "----End-----");}

Commonly used time-lapse execution