15-RunLoop-02

一、RunLoop运行逻辑

• 1.源码分析：精简版（保留了核心代码）
  

• 2.休眠细节
  

二、RunLoop在实际开发中的应用

• 1.处理滑动scrollview时NSTimer失效
  

  

• 2.线程保活

  • 1.在子线程中创建一个RunLoop
  • 2.往RunLoop里面添加Source\Timer\Observer保证RunLoop不立刻退出
  • 3.[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];方法保证RunLoop持续运行
  • 4.在子线程调用方法（waitUntilDone设置为YES，代表子线程的代码执行完毕后，这个方法才会往下走）
  • 5.只要RunLoop退出，该子线程就不能再用了。
    代码：

------------------------------------MJThread.h--------------------------------
#import <Foundation/Foundation.h>

@interface MJThread : NSThread

@end
------------------------------------MJThread.m----------------------------------
#import "MJThread.h"

@implementation MJThread

- (void)dealloc
{
    NSLog(@"%s", __func__);
}

@end
----------------------------------------------ViewController.h---------------------------------------
#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end
----------------------------------------------ViewController.m---------------------------------------
#import "ViewController.h"
#import "MJThread.h"

@interface ViewController ()
@property (strong, nonatomic) MJThread *thread;
@property (assign, nonatomic, getter=isStoped) BOOL stopped;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    __weak typeof(self) weakSelf = self;
    
    self.stopped = NO;
    self.thread = [[MJThread alloc] initWithBlock:^{
        NSLog(@"%@----begin----", [NSThread currentThread]);
        
        // 往RunLoop里面添加Source\Timer\Observer保证RunLoop不立刻退出。
        [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSDefaultRunLoopMode];

        //while这个方法保证RunLoop持续运行，有事情时处理事情，没事情时就休眠。
        while (weakSelf && !weakSelf.isStoped) {
            //这个方法执行完任务后就退出了
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
        }
        
        NSLog(@"%@----end----", [NSThread currentThread]);
    }];
    [self.thread start];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    //只要RunLoop退出，该子线程就不能再用了。
    if (!self.thread) return;
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
}

// 子线程需要执行的任务
- (void)test
{
    NSLog(@"%s %@", __func__, [NSThread currentThread]);
}

//控制器中的Button
- (IBAction)stop {
    //只要RunLoop退出，该子线程就不能再用了。
    if (!self.thread) return;
    
    // 在子线程调用stop（waitUntilDone设置为YES，代表子线程的代码执行完毕后，这个方法才会往下走）
    [self performSelector:@selector(stopThread) onThread:self.thread withObject:nil waitUntilDone:YES];
}

// 用于停止子线程的RunLoop
- (void)stopThread
{
    // 设置标记为YES
    self.stopped = YES;
    
    // 停止RunLoop,
    CFRunLoopStop(CFRunLoopGetCurrent());
    NSLog(@"%s %@", __func__, [NSThread currentThread]);
    
    // 清空线程
    self.thread = nil;
}

- (void)dealloc
{
    NSLog(@"%s", __func__);
    
    [self stop];
}

@end

三、线程的封装

• OC

-------------------------------------------------MJPermenantThread.h--------------------------------------------
#import <Foundation/Foundation.h>

typedef void (^MJPermenantThreadTask)(void);

@interface MJPermenantThread : NSObject

/**
 开启线程
 */
//- (void)run;

/**
 在当前子线程执行一个任务
 */
- (void)executeTask:(MJPermenantThreadTask)task;

/**
 结束线程
 */
- (void)stop;

@end
------------------------------------------------MJPermenantThread.m--------------------------------------------
#import "MJPermenantThread.h"

/** MJThread **/
@interface MJThread : NSThread
@end
@implementation MJThread
- (void)dealloc
{
    NSLog(@"%s", __func__);
}
@end

/** MJPermenantThread **/
@interface MJPermenantThread()
@property (strong, nonatomic) MJThread *innerThread;
@property (assign, nonatomic, getter=isStopped) BOOL stopped;
@end

@implementation MJPermenantThread
#pragma mark - public methods
- (instancetype)init
{
    if (self = [super init]) {
        self.stopped = NO;
        
        __weak typeof(self) weakSelf = self;
        
        self.innerThread = [[MJThread alloc] initWithBlock:^{
            [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSDefaultRunLoopMode];
            
            while (weakSelf && !weakSelf.isStopped) {
                [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
            }
        }];
        
        [self.innerThread start];
    }
    return self;
}

//- (void)run
//{
//    if (!self.innerThread) return;
//
//    [self.innerThread start];
//}

- (void)executeTask:(MJPermenantThreadTask)task
{
    if (!self.innerThread || !task) return;
    
    [self performSelector:@selector(__executeTask:) onThread:self.innerThread withObject:task waitUntilDone:NO];
}

- (void)stop
{
    if (!self.innerThread) return;
    
    [self performSelector:@selector(__stop) onThread:self.innerThread withObject:nil waitUntilDone:YES];
}

- (void)dealloc
{
    NSLog(@"%s", __func__);
    
    [self stop];
}

#pragma mark - private methods
- (void)__stop
{
    self.stopped = YES;
    CFRunLoopStop(CFRunLoopGetCurrent());
    self.innerThread = nil;
}

- (void)__executeTask:(MJPermenantThreadTask)task
{
    task();
}

@end

• 2.C

------------------------------------------------MJPermenantThread.h---------------------------------------------
#import <Foundation/Foundation.h>

typedef void (^MJPermenantThreadTask)(void);

@interface MJPermenantThread : NSObject

/**
 开启线程
 */
//- (void)run;

/**
 在当前子线程执行一个任务
 */
- (void)executeTask:(MJPermenantThreadTask)task;

/**
 结束线程
 */
- (void)stop;

@end
---------------------------------------------------MJPermenantThread.m---------------------------------------
#import "MJPermenantThread.h"

/** MJThread **/
@interface MJThread : NSThread
@end
@implementation MJThread
- (void)dealloc
{
    NSLog(@"%s", __func__);
}
@end

/** MJPermenantThread **/
@interface MJPermenantThread()
@property (strong, nonatomic) MJThread *innerThread;
@end

@implementation MJPermenantThread
#pragma mark - public methods
- (instancetype)init
{
    if (self = [super init]) {
        self.innerThread = [[MJThread alloc] initWithBlock:^{
            NSLog(@"begin----");
            
            // 创建上下文（要初始化一下结构体）
            CFRunLoopSourceContext context = {0};
            
            // 创建source
            CFRunLoopSourceRef source = CFRunLoopSourceCreate(kCFAllocatorDefault, 0, &context);
            
            // 往Runloop中添加source
            CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopDefaultMode);
            
            // 销毁source
            CFRelease(source);
            
            // 启动
            CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0e10, false);
            
//            while (weakSelf && !weakSelf.isStopped) {
//                // 第3个参数：returnAfterSourceHandled，设置为true，代表执行完source后就会退出当前loop
//                CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0e10, true);
//            }
            
            NSLog(@"end----");
        }];
        
        [self.innerThread start];
    }
    return self;
}

//- (void)run
//{
//    if (!self.innerThread) return;
//
//    [self.innerThread start];
//}

- (void)executeTask:(MJPermenantThreadTask)task
{
    if (!self.innerThread || !task) return;
    
    [self performSelector:@selector(__executeTask:) onThread:self.innerThread withObject:task waitUntilDone:NO];
}

- (void)stop
{
    if (!self.innerThread) return;
    
    [self performSelector:@selector(__stop) onThread:self.innerThread withObject:nil waitUntilDone:YES];
}

- (void)dealloc
{
    NSLog(@"%s", __func__);
    
    [self stop];
}

#pragma mark - private methods
- (void)__stop
{
    CFRunLoopStop(CFRunLoopGetCurrent());
    self.innerThread = nil;
}

- (void)__executeTask:(MJPermenantThreadTask)task
{
    task();
}

@end