[iOS]浅谈NSRunloop工作原理和相关应用

 1 #import <UIKit/UIKit.h>
 2 
 3 #import "AppDelegate.h"
 4 
 5 int main(int argc, char * argv[]) {
 6 
 7     @autoreleasepool {
 8 
 9         return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
10 
11     }
12 
13 }

 1 int main(int argc, char * argv[]) {
 2 
 3   BOOL runnning =YES;
 4    do{
 5         ...
 6        //处理各种操作 各种事件
 7        ...
 8       }while(running);
 9   
10     return 0;
11 }    

 1 // should only be called by Foundation
 2 // t==0 is a synonym for "main thread" that always works
 3 
 4 //函数返回值为CFRunLoopRef  形参类型为pthread_t 根据线程创建runloop对象
 5 
 6 CF_EXPORT CFRunLoopRef _CFRunLoopGet0(pthread_t t) {
 7 
 8     if (pthread_equal(t, kNilPthreadT)) {
 9 
10 t = pthread_main_thread_np();
11 
12     }
13 
14     __CFLock(&loopsLock);
15 
16     if (!__CFRunLoops) {
17 
18         __CFUnlock(&loopsLock);
19 
20 CFMutableDictionaryRef dict = CFDictionaryCreateMutable(kCFAllocatorSystemDefault, 0, NULL, &kCFTypeDictionaryValueCallBacks);
21 
22 //由此句可得出  调用其他线程NSRunloop对象也会首先创建主线程NSRunloop对象
23 CFRunLoopRef mainLoop = __CFRunLoopCreate(pthread_main_thread_np());
24 
25 CFDictionarySetValue(dict, pthreadPointer(pthread_main_thread_np()), mainLoop);
26 
27 if (!OSAtomicCompareAndSwapPtrBarrier(NULL, dict, (void * volatile *)&__CFRunLoops)) {
28 
29     CFRelease(dict);
30 
31 }
32 
33 CFRelease(mainLoop);
34 
35         __CFLock(&loopsLock);
36 
37     }
38 
39     CFRunLoopRef loop = (CFRunLoopRef)CFDictionaryGetValue(__CFRunLoops, pthreadPointer(t));
40 
41     __CFUnlock(&loopsLock);
42 
43     if (!loop) {
44 
45 CFRunLoopRef newLoop = __CFRunLoopCreate(t);
46 
47         __CFLock(&loopsLock);
48 
49 loop = (CFRunLoopRef)CFDictionaryGetValue(__CFRunLoops, pthreadPointer(t));
50 
51 if (!loop) {
52 
53     CFDictionarySetValue(__CFRunLoops, pthreadPointer(t), newLoop);
54 
55     loop = newLoop;
56 
57 }
58
59         // don‘t release run loops inside the loopsLock, because CFRunLoopDeallocate may end up taking it
60 
61         __CFUnlock(&loopsLock);
62 
63 CFRelease(newLoop);
64 
65     }
66 
67     if (pthread_equal(t, pthread_self())) {
68 
69         _CFSetTSD(__CFTSDKeyRunLoop, (void *)loop, NULL);
70 
71         if (0 == _CFGetTSD(__CFTSDKeyRunLoopCntr)) {
72 
73             _CFSetTSD(__CFTSDKeyRunLoopCntr, (void *)(PTHREAD_DESTRUCTOR_ITERATIONS-1), (void (*)(void *))__CFFinalizeRunLoop);
74 
75         }
76     }
77     return loop;
78 }

 [NSTimer scheduledTimerWithTimeInterval:<#(NSTimeInterval)#> target:<#(nonnull id)#> selector:<#(nonnull SEL)#> userInfo:<#(nullable id)#> repeats:<#(BOOL)#>]

1  NSTimer * timer =[NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(test) userInfo:nil repeats:YES];
2     [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes]; //手动添加到runloop  可以指定Mode

 1 /* Run Loop Observer Activities */
 2 
 3 typedef CF_OPTIONS(CFOptionFlags, CFRunLoopActivity) {
 4 
 5     kCFRunLoopEntry = (1UL << 0),
 6 
 7     kCFRunLoopBeforeTimers = (1UL << 1),
 8 
 9     kCFRunLoopBeforeSources = (1UL << 2),
10 
11     kCFRunLoopBeforeWaiting = (1UL << 5),
12 
13     kCFRunLoopAfterWaiting = (1UL << 6),
14 
15     kCFRunLoopExit = (1UL << 7),
16 
17     kCFRunLoopAllActivities = 0x0FFFFFFFU
18 
19 };

1 //   通过添加port 或者timer
2 
3  [[NSRunLoop currentRunLoop] addPort:[NSPort port] forMode:NSDefaultRunLoopMode];
4 
5 [[NSRunLoop currentRunLoop] run];