RunLoop（二）

2019-04-12 本文已影响0人 dandelionYD

RunLoop的运行逻辑

本文Demo代码可见gitHub_Demo

runloop_03.png

runloop_04.png

runloop_05.png

查看源码：

CF-1151.16 CFRunLoop.c

1.CFRunLoopRunSpecific（RunLoop的实现）
2.CFRunLoopRunInMode（用指定的Mode启动，允许设置RunLoop超时时间）
3.__CFRunLoopRun（RunLoop的执行）

RunLoop休眠的实现原理(如果想看更加具体的详见：深入理解RunLoop)

runloop_06.png

苹果用 RunLoop 实现的功能（详见：深入理解RunLoop）
- 手势识别
- 界面更新
- 定时器
- PerformSelector
- AutoreleasePool
- 事件响应
- 关于GCD
- 网络请求
- ...

我们在开发中的使用

NSTimer在滑动时停止工作的问题
控制线程生命周期（线程保活）
监控应用卡顿
性能优化
...

 NSTimer失效：
 我们现在界面先创建一个UITextView、
 
 static int count = 0;
 NSTimer *timer = [NSTimer timerWithTimeInterval:1.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
        NSLog(@"%d", ++count);
 }];

 //该模式下：滚动UITextView-->timer不会打印、松开则继续打印
 [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
 
 //该模式下：可以正常的打印
 // NSDefaultRunLoopMode、UITrackingRunLoopMode才是真正存在的模式
 // NSRunLoopCommonModes并不是一个真的模式，它只是一个标记
 // timer能在_commonModes数组中存放的模式下工作
 [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
 
 
 ==================================
应用卡顿检测：
平时所说的“卡顿"主要是因为在主线程执行了比较耗时的操作 
可以添加Observer到主线程RunLoop中，通过监听RunLoop状态切换的耗时，以达到监控卡顿的目的
使用：https://github.com/UIControl/LXDAppFluecyMonitor

===================================

性能优化：
使用：https://www.jianshu.com/p/30f7ced70083
Demo地址：https://github.com/qiaoyoung/RunLoop

下面我们看看怎样，线程保活？

Test01:

YDThread1.h
#import <Foundation/Foundation.h>
@interface YDThread1 : NSThread
@end

YDThread1.m
#import "YDThread1.h"
@implementation YDThread1
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

TestVC01.m
#import "TestVC01.h"
#import "YDThread1.h"

@implementation TestVC01
-(void)viewDidLoad{
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor whiteColor];
    
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    YDThread1 *thread = [[YDThread1 alloc]initWithTarget:self selector:@selector(run) object:nil];
    [thread start];
}
-(void)run{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}
@end

打印：
Runloop[2520:239171] -[TestVC01 run] - <YDThread1: 0x6000018c2440>{number = 3, name = (null)}
Runloop[2520:239171] -[YDThread1 dealloc]
Runloop[2520:239175] -[TestVC01 run] - <YDThread1: 0x6000018c1b40>{number = 4, name = (null)}
Runloop[2520:239175] -[YDThread1 dealloc]
Runloop[2520:239205] -[TestVC01 run] - <YDThread1: 0x6000018ce9c0>{number = 5, name = (null)}
Runloop[2520:239205] -[YDThread1 dealloc]

说明：
每次点击总会创建一个子线程来处理事件（执行完会自动释放）
这样会很消耗资源

Test02:

YDThread2.h
#import <Foundation/Foundation.h>
@interface YDThread2 : NSThread
@end

YDThread2.m
#import "YDThread2.h"
@implementation YDThread2
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

TestVC02.m
#import "TestVC02.h"
#import "YDThread2.h"

@interface TestVC02 ()
@property (nonatomic,strong)YDThread2 *thread;
@end

@implementation TestVC02
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    self.thread = [[YDThread2 alloc]initWithTarget:self selector:@selector(run) object:nil]; //循环引用啦
    [self.thread start];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
//    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:YES]; //YES会崩溃
   //如果CPU在运行当前线程对象的时候线程任务执行完毕\异常强制退出，则当前线程对象进入死亡状态
    NSLog(@"123");
}

-(void)test{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

-(void)run{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

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

打印：
Runloop[2666:248192] -[TestVC02 run] - <YDThread2: 0x600002265480>{number = 4, name = (null)}
Runloop[2666:247106] 123
Runloop[2666:247106] 123
Runloop[2666:247106] 123
Runloop[2666:247106] 123
Runloop[2666:247106] 123
Runloop[2666:247106] 123

Test03:

YDThread3.h
#import <Foundation/Foundation.h>
@interface YDThread3 : NSThread
@end

YDThread3.m
#import "YDThread3.h"
@implementation YDThread3
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

TestVC03.h
#import <UIKit/UIKit.h>
@interface TestVC03 : UIViewController
@end

TestVC03.m
#import "TestVC03.h"
#import "YDThread3.h"

@interface TestVC03 ()
@property (nonatomic,strong)YDThread3   *thread;
@end

@implementation TestVC03
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    self.thread = [[YDThread3 alloc] initWithBlock:^{
        NSLog(@"%s %@", __func__, [NSThread currentThread]);
        NSLog(@"%@----begin----", [NSThread currentThread]);
        // 往RunLoop里面添加Source\Timer\Observer (这样RunLoop才有效)
        [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSDefaultRunLoopMode];
        [[NSRunLoop currentRunLoop] run];
        NSLog(@"%s ----end----", __func__);
    }];
    [self.thread start];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
    NSLog(@"123");
}

-(void)test{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

/*
//这样控制器可以被释放了，但是thread没有被释放
-(void)dealloc{
    NSLog(@"%s",__func__);
}
 */


/*
//这样也不会被释放  代码一直会卡在 [[NSRunLoop currentRunLoop] run];这里，任务还没结束，线程就不会死
-(void)dealloc{
    NSLog(@"%s",__func__);
    self.thread = nil ;
}
*/

//这样 写也不对：这样只是在停掉主线程的RunLoop并非该RunLoop
-(void)dealloc{
    // 停止RunLoop
    CFRunLoopStop(CFRunLoopGetCurrent());
    NSLog(@"%s",__func__);
}
@end

Test04:

YDThread4.h
#import <Foundation/Foundation.h>
@interface YDThread4 : NSThread
@end

YDThread4.m
#import "YDThread4.h"
@implementation YDThread4
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

TestVC04.h
#import <UIKit/UIKit.h>
@interface TestVC04 : UIViewController
@end

TestVC04.m
#import "TestVC04.h"
#import "YDThread4.h"

@interface TestVC04 ()
@property (nonatomic,strong)YDThread4   *thread;
@end

@implementation TestVC04
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    
    //控制器销毁了，但是线程还在  NSRunLoop的run方法是无法停止的，它专门用于开启一个永不销毁的线程（NSRunLoop）
    self.thread = [[YDThread4 alloc] initWithBlock:^{
        NSLog(@"%s %@", __func__, [NSThread currentThread]);
        NSLog(@"%@----begin----", [NSThread currentThread]);
        // 往RunLoop里面添加Source\Timer\Observer (这样RunLoop才有效)
        [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSDefaultRunLoopMode];
        [[NSRunLoop currentRunLoop] run];
        NSLog(@"%s ----end----", __func__);
    }];
    [self.thread start];
    
    /*
    //这样写：只会执行一次，自动会结束的哟
    self.thread = [[YDThread4 alloc] initWithBlock:^{
        NSLog(@"%@----begin----", [NSThread currentThread]);
            // 往RunLoop里面添加Source\Timer\Observer
            [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSDefaultRunLoopMode];
        
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
            NSLog(@"%@----end----", [NSThread currentThread]);
        }];
    [self.thread start];
   */
    
    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 100, 100, 60)];
    [self.view addSubview:btn];
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [btn setTitle:@"stop" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(stopClick) forControlEvents:UIControlEventTouchUpInside];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
    NSLog(@"123");
}

-(void)test{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

- (void)stopClick{
    [self performSelector:@selector(stop1) onThread:self.thread withObject:nil waitUntilDone:NO];
}

// 用于停止子线程的RunLoop
-(void)stop1{
    // 停止RunLoop
    CFRunLoopStop(CFRunLoopGetCurrent());
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

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

Test05:

YDThread5.h
#import <Foundation/Foundation.h>
@interface YDThread5 : NSThread
@end

YDThread5.m
#import "YDThread5.h"
@implementation YDThread5
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

TestVC05.h
#import <UIKit/UIKit.h>
@interface TestVC05 : UIViewController
@end

TestVC05.m
#import "TestVC05.h"
#import "YDThread5.h"

@interface TestVC05 ()
@property (nonatomic,strong)YDThread5   *thread;
@property (assign, nonatomic, getter=isStoped) BOOL stopped;
@end

@implementation TestVC05
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    
    __weak typeof(self) weakSelf = self;
    self.stopped = NO;
    self.thread = [[YDThread5 alloc] initWithBlock:^{
        NSLog(@"%s %@", __func__, [NSThread currentThread]);
        NSLog(@"%@----begin----", [NSThread currentThread]);
        while (!weakSelf.isStoped) {
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
        }
        NSLog(@"%s ----end----", __func__);
     }];
    [self.thread start];

    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 100, 100, 60)];
    [self.view addSubview:btn];
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [btn setTitle:@"stop" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(stopClick) forControlEvents:UIControlEventTouchUpInside];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
    NSLog(@"123");
}

-(void)test{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

- (void)stopClick{
    [self performSelector:@selector(stop1) onThread:self.thread withObject:nil waitUntilDone:NO];
}

// 用于停止子线程的RunLoop
-(void)stop1{
    // 设置标记为NO
    self.stopped = YES;
    // 停止RunLoop
    CFRunLoopStop(CFRunLoopGetCurrent());
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
    
    //这样：主动点击stop，线程会跟随控制器而销毁，
    
    //但是如果直接点击返回，会崩溃，
    // [self performSelector:@selector(stop1) onThread:self.thread withObject:nil waitUntilDone:NO];
    //这样并未等子线程执行完 就执行了 "}"了，之后执行dealloc方法，控制器为nil，所以会出现坏内存访问 （vc没了）
}

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

Test06(终结版本):

YDThread6.h
#import <Foundation/Foundation.h>
@interface YDThread6 : NSThread
@end

YDThread6.m
#import "YDThread6.h"
@implementation YDThread6
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end


TestVC06.h
#import <UIKit/UIKit.h>
@interface TestVC06 : UIViewController
@end

TestVC06.m
#import "TestVC06.h"
#import "YDThread6.h"

@interface TestVC06 ()
@property (nonatomic,strong)YDThread6 *thread;
@property (assign, nonatomic, getter=isStoped) BOOL stopped;
@end

@implementation TestVC06
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    __weak typeof(self) weakSelf = self;
    self.stopped = NO;
    self.thread = [[YDThread6 alloc] initWithBlock:^{
        NSLog(@"%@----begin----", [NSThread currentThread]);
        while (weakSelf && !weakSelf.isStoped) {
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
        }
        NSLog(@"%s ----end----", __func__);
    }];
    [self.thread start];
    
    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 100, 100, 60)];
    [self.view addSubview:btn];
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [btn setTitle:@"stop" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(stopClick) forControlEvents:UIControlEventTouchUpInside];
    
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    if (!self.thread) return;
    [self performSelector:@selector(test) onThread:self.thread withObject:nil waitUntilDone:NO];
}

-(void)test{
    NSLog(@"%s - %@",__func__,[NSThread currentThread]);
}

-(void)stopClick{
    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];
}

-(void)stopThread{
    // 设置标记为NO
    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 stopClick];
}
@end

封装

YDPermenantThread.h
#import <Foundation/Foundation.h>
typedef void (^YDPermenantThreadTask)(void);
@interface YDPermenantThread : NSObject
/**
 在当前子线程执行一个任务
 */
- (void)executeTask:(YDPermenantThreadTask)task;

/**
 结束线程
 */
- (void)stop;
@end

YDPermenantThread.m
#import "YDPermenantThread.h"
@interface YDThread : NSThread
@end

@implementation YDThread
-(void)dealloc{
    NSLog(@"%s",__FUNCTION__);
}
@end

@interface YDPermenantThread()
@property (nonatomic,strong)YDThread  *myThread;
@property (assign, nonatomic, getter=isStopped) BOOL stopped;
@end

@implementation YDPermenantThread
-(instancetype)init{
    if(self = [super init]){
        self.stopped = NO;
        __weak typeof(self) weakSelf = self;
        self.myThread = [[YDThread alloc]initWithBlock:^{
            [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc]init] forMode:NSDefaultRunLoopMode];
            while (weakSelf && !weakSelf.isStopped) {
                 [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
            }
        }];
        [self.myThread start];
    }return self;
}

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

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

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

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

- (void)__executeTask:(YDPermenantThreadTask)task{
    task();
}
@end


TestVC07.h
#import <UIKit/UIKit.h>
@interface TestVC07 : UIViewController
@end

TestVC07.m
#import "TestVC07.h"
#import "YDPermenantThread.h"
@interface TestVC07 ()
@property (nonatomic,strong)YDPermenantThread  *thread;
@end

@implementation TestVC07
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    self.thread = [[YDPermenantThread alloc]init];
    
    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 100, 100, 60)];
    [self.view addSubview:btn];
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [btn setTitle:@"stop" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(stopClick) forControlEvents:UIControlEventTouchUpInside];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self.thread executeTask:^{
         NSLog(@"Do something- %@", [NSThread currentThread]);
    }];
}

-(void)stopClick{
    [self.thread stop];
}

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

总结：

1.线程的任务一旦执行完毕，生命周期就结束，无法再使用（没有使用runloop保活）
2.保住线程的命为什么要用runloop，用强指针不就好了么？
  准确来讲，使用runloop是为了让线程保持激活状态
  主线程几乎所有的事情都是交给了runloop去做，比如UI界面的刷新、点击时间的处理、performSelector等等

友情链接：

RunLoop（二）

RunLoop的运行逻辑

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