Multi-threaded usage in IOS development

One, five ways to create multi-threading

1. How to turn on threading

    Nsthread * Thread=[[nsthread alloc] initwithtarget:self selector: @selector (_update) Object:nil];

2. How to turn on threading method two

    [Nsthread detachnewthreadselector: @selector (_update) totarget:self Withobject:nil];

3. How to turn on threading three

    [Self Performselectorinbackground: @selector (_update) Withobject:nil];

4. How to turn on threading four

    Nsoperationqueue *queue=[[nsoperationqueue alloc] init];    [Queue addoperationwithblock:^{for        (int i=0;i<50;i++) {            printf ("sub-thread \ n");        }    ];

5. How to turn on threading five

<pre name= "code" class= "OBJC" >    //First step to open thread pool        nsoperationqueue * Queue=[[nsoperationqueue alloc] init];    Set number of concurrent    [queue setmaxconcurrentoperationcount:2];        Second create multithreaded add to thread pool    nsinvocationoperation * thread1=[[nsinvocationoperation alloc] initwithtarget:self selector:@ Selector (_update1) Object:nil];    Nsinvocationoperation *thread2=[[nsinvocationoperation alloc] initwithtarget:self selector: @selector (_UPDATE2) Object:nil];        [Thread1 Setqueuepriority:nsoperationqueuepriorityverylow];    [Thread2 Setqueuepriority:nsoperationqueuepriorityveryhigh];        [Queue addoperation:thread1];    [Queue addoperation:thread2];

Second, multi-threaded application examples, loading pictures.

1. Core Ideas

Consider that if loading a network picture is delayed, in one mainline preempted will affect the rendering of the control, at which point you can take multi-threading and refresh the UI after the asynchronous loading is complete.

2. Realization of Ideas

Multi-threaded downloads are achieved by adding classes to the Uiimageview.

　　Main code:

#import "Uiimageview+thread.h" @implementation uiimageview (load)-(void) Setimagewithurl: (NSString *) url{    [self Performselectorinbackground: @selector (_loadimage:) Withobject:url];} -(void) _loadimage: (NSString *) u{    @autoreleasepool {                nsurl *url=[nsurl urlwithstring:u];        NSData *data=[nsdata Datawithcontentsofurl:url];        UIImage *image=[uiimage Imagewithdata:data];                [Self Performselectoronmainthread: @selector (setimage:) withobject:image waituntildone:no];            }}

Multi-threaded usage in IOS development