关于iOS多线程的总结

关于iOS多线程的总结

Swift

Objective-c

概述

4

Pthreads

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
pthread_t thread;
//创建一个线程并自动执行
pthread_create(&thread, NULL, start, NULL);
}

void *start(void *data) {
NSLog(@"%@", [NSThread currentThread]);

return NULL;
}

swift1.2

CFunctionPointer<T>

swift 2.0

@convention(c)

Pthreads

NSThread

[NSThread currentThread]

创建并启动

// 创建
NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(run:) object:nil];

// 启动
[thread start];

//创建
let thread = NSThread(target: self, selector: "run:", object: nil)

//启动
thread.start()

[NSThread detachNewThreadSelector:@selector(run:) toTarget:self withObject:nil];

NSThread.detachNewThreadSelector("run:", toTarget: self, withObject: nil)

[self performSelectorInBackground:@selector(run:) withObject:nil];

performSelector:

其他方法

//取消线程
- (void)cancel;

//启动线程
- (void)start;

//判断某个线程的状态的属性
@property (readonly, getter=isExecuting) BOOL executing;
@property (readonly, getter=isFinished) BOOL finished;
@property (readonly, getter=isCancelled) BOOL cancelled;

//设置和获取线程名字
-(void)setName:(NSString *)n;
-(NSString *)name;

//获取当前线程信息
+ (NSThread *)currentThread;

//获取主线程信息
+ (NSThread *)mainThread;

//使当前线程暂停一段时间，或者暂停到某个时刻
+ (void)sleepForTimeInterval:(NSTimeInterval)time;
+ (void)sleepUntilDate:(NSDate *)date;

GCD

Grand Central Dispatch

c语言

GCD

任务和队列

GCD

是否会创建新的线程

同步（sync）

异步（async）

Block

同步（sync）

Block

异步（async）

FIFO（先进先出）

FIFO

创建队列

串行队列

//OBJECTIVE-C
dispatch_queue_t queue = ispatch_get_main_queue();

//SWIFT
let queue = ispatch_get_main_queue()

串行队列

串行队列

并行队列

DISPATCH_QUEUE_SERIAL

NULL

DISPATCH_QUEUE_CONCURRENT

//OBJECTIVE-C
//串行队列
dispatch_queue_t queue = dispatch_queue_create("tk.bourne.testQueue", NULL);
dispatch_queue_t queue = dispatch_queue_create("tk.bourne.testQueue", DISPATCH_QUEUE_SERIAL);
//并行队列
dispatch_queue_t queue = dispatch_queue_create("tk.bourne.testQueue", DISPATCH_QUEUE_CONCURRENT);

//SWIFT
//串行队列
let queue = dispatch_queue_create("tk.bourne.testQueue", nil);
let queue = dispatch_queue_create("tk.bourne.testQueue", DISPATCH_QUEUE_SERIAL)
//并行队列
let queue = dispatch_queue_create("tk.bourne.testQueue", DISPATCH_QUEUE_CONCURRENT)

//OBJECTIVE-C
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

//SWIFT
let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

创建任务

dispatch_sync(<#queue#>, ^{
//code here
NSLog(@"%@", [NSThread currentThread]);
});

dispatch_sync(<#queue#>, { () -> Void in
//code here
println(NSThread.currentThread())
})

dispatch_async(<#queue#>, ^{
//code here
NSLog(@"%@", [NSThread currentThread]);
});

dispatch_async(<#queue#>, { () -> Void in
//code here
println(NSThread.currentThread())
})

NSLog("之前 - %@", NSThread.currentThread())
dispatch_sync(dispatch_get_main_queue(), { () -> Void in
NSLog("sync - %@", NSThread.currentThread())
})
NSLog("之后 - %@", NSThread.currentThread())

之前 - <NSThread: 0x7fb3a9e16470>{number = 1, name = main}

dispatch_sync

main_queue

main_queue

dispatch_sync

let queue = dispatch_queue_create("myQueue", DISPATCH_QUEUE_SERIAL)

NSLog("之前 - %@", NSThread.currentThread())

dispatch_async(queue, { () -> Void in
NSLog("sync之前 - %@", NSThread.currentThread())
dispatch_sync(queue, { () -> Void in
NSLog("sync - %@", NSThread.currentThread())
})
NSLog("sync之后 - %@", NSThread.currentThread())
})

NSLog("之后 - %@", NSThread.currentThread())

sync - %@

sync之后 - %@

DISPATCH_QUEUE_SERIAL

之前 - %@

dispatch_async

之后 - %@

sync之前 - %@

dispatch_sync

sync

sync

queue

queue

sync

queue

sync

sync

队列组

//1.创建队列组
dispatch_group_t group = dispatch_group_create();
//2.创建队列
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

//3.多次使用队列组的方法执行任务, 只有异步方法
//3.1.执行3次循环
dispatch_group_async(group, queue, ^{
for (NSInteger i = 0; i < 3; i++) {
NSLog(@"group-01 - %@", [NSThread currentThread]);
}
});

//3.2.主队列执行8次循环
dispatch_group_async(group, dispatch_get_main_queue(), ^{
for (NSInteger i = 0; i < 8; i++) {
NSLog(@"group-02 - %@", [NSThread currentThread]);
}
});

//3.3.执行5次循环
dispatch_group_async(group, queue, ^{
for (NSInteger i = 0; i < 5; i++) {
NSLog(@"group-03 - %@", [NSThread currentThread]);
}
});

//4.都完成后会自动通知
dispatch_group_notify(group, dispatch_get_main_queue(), ^{
NSLog(@"完成 - %@", [NSThread currentThread]);
});

//1.创建队列组
let group = dispatch_group_create()
//2.创建队列
let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

//3.多次使用队列组的方法执行任务, 只有异步方法
//3.1.执行3次循环
dispatch_group_async(group, queue) { () -> Void in
for _ in 0..<3 {
NSLog("group-01 - %@", NSThread.currentThread())
}
}

//3.2.主队列执行8次循环
dispatch_group_async(group, dispatch_get_main_queue()) { () -> Void in
for _ in 0..<8 {
NSLog("group-02 - %@", NSThread.currentThread())
}
}

//3.3.执行5次循环
dispatch_group_async(group, queue) { () -> Void in
for _ in 0..<5 {
NSLog("group-03 - %@", NSThread.currentThread())
}
}

//4.都完成后会自动通知
dispatch_group_notify(group, dispatch_get_main_queue()) { () -> Void in
NSLog("完成 - %@", NSThread.currentThread())
}

func dispatch_barrier_async(_ queue: dispatch_queue_t, _ block: dispatch_block_t)

DISPATCH_QUEUE_CONCURRENT

dispatch_async

func dispatch_barrier_sync(_ queue: dispatch_queue_t, _ block: dispatch_block_t)

dispatch_sync

NSOperation和NSOperationQueue

NSOperation 和 NSOperationQueue

任务 和 队列

NSOperation

NSOperationQueue

添加任务

NSOperation

NSInvocationOperation

NSBlockOperation

start

cancel

//1.创建NSInvocationOperation对象
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(run) object:nil];

//2.开始执行
[operation start];

NSInvocationOperation

//1.创建NSBlockOperation对象
NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"%@", [NSThread currentThread]);
}];

//2.开始任务
[operation start];

//1.创建NSBlockOperation对象
let operation = NSBlockOperation { () -> Void in
println(NSThread.currentThread())
}

//2.开始任务
operation.start()

NSBlockOperation

addExecutionBlock:

//1.创建NSBlockOperation对象
NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"%@", [NSThread currentThread]);
}];

//添加多个Block
for (NSInteger i = 0; i < 5; i++) {
[operation addExecutionBlock:^{
NSLog(@"第%ld次：%@", i, [NSThread currentThread]);
}];
}

//2.开始任务
[operation start];

//1.创建NSBlockOperation对象
let operation = NSBlockOperation { () -> Void in
NSLog("%@", NSThread.currentThread())
}

//2.添加多个Block
for i in 0..<5 {
operation.addExecutionBlock { () -> Void in
NSLog("第%ld次 - %@", i, NSThread.currentThread())
}
}

//2.开始任务
operation.start()

addExecutionBlock

start()

NSLog()

println()

print() / println()

println()

NSLog()

println()

NSOperation

main()

start()

main()

cancel()

创建队列

NSOperation

start()

addExecutionBlock

NSOperationQueue

//OBJECTIVE-C
NSOperationQueue *queue = [NSOperationQueue mainQueue];

//SWIFT
let queue = NSOperationQueue.mainQueue()

//1.创建一个其他队列
NSOperationQueue *queue = [[NSOperationQueue alloc] init];

//2.创建NSBlockOperation对象
NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"%@", [NSThread currentThread]);
}];

//3.添加多个Block
for (NSInteger i = 0; i < 5; i++) {
[operation addExecutionBlock:^{
NSLog(@"第%ld次：%@", i, [NSThread currentThread]);
}];
}

//4.队列添加任务
[queue addOperation:operation];

//1.创建其他队列
let queue = NSOperationQueue()

//2.创建NSBlockOperation对象
let operation = NSBlockOperation { () -> Void in
NSLog("%@", NSThread.currentThread())
}

//3.添加多个Block
for i in 0..<5 {
operation.addExecutionBlock { () -> Void in
NSLog("第%ld次 - %@", i, NSThread.currentThread())
}
}

//4.队列添加任务
queue.addOperation(operation)

NSOperationQueue

GCD的队列

NSOperationQueue

maxConcurrentOperationCount

1

NSOperationQueue

- (void)addOperationWithBlock:(void (^)(void))block;

NSOperation

//1.任务一：下载图片
NSBlockOperation *operation1 = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"下载图片 - %@", [NSThread currentThread]);
[NSThread sleepForTimeInterval:1.0];
}];

//2.任务二：打水印
NSBlockOperation *operation2 = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"打水印   - %@", [NSThread currentThread]);
[NSThread sleepForTimeInterval:1.0];
}];

//3.任务三：上传图片
NSBlockOperation *operation3 = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"上传图片 - %@", [NSThread currentThread]);
[NSThread sleepForTimeInterval:1.0];
}];

//4.设置依赖
[operation2 addDependency:operation1];      //任务二依赖任务一
[operation3 addDependency:operation2];      //任务三依赖任务二

//5.创建队列并加入任务
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
[queue addOperations:@[operation3, operation2, operation1] waitUntilFinished:NO];

//1.任务一：下载图片
let operation1 = NSBlockOperation { () -> Void in
NSLog("下载图片 - %@", NSThread.currentThread())
NSThread.sleepForTimeInterval(1.0)
}

//2.任务二：打水印
let operation2 = NSBlockOperation { () -> Void in
NSLog("打水印   - %@", NSThread.currentThread())
NSThread.sleepForTimeInterval(1.0)
}

//3.任务三：上传图片
let operation3 = NSBlockOperation { () -> Void in
NSLog("上传图片 - %@", NSThread.currentThread())
NSThread.sleepForTimeInterval(1.0)
}

//4.设置依赖
operation2.addDependency(operation1)    //任务二依赖任务一
operation3.addDependency(operation2)    //任务三依赖任务二

//5.创建队列并加入任务
let queue = NSOperationQueue()
queue.addOperations([operation3, operation2, operation1], waitUntilFinished: false)

removeDependency

其他方法

其他用法

线程同步

@synchronized(self) {
//需要执行的代码块
}

objc_sync_enter(self)
//需要执行的代码块
objc_sync_exit(self)

GCD

NSOperation

//GCD
//需要一个全局变量queue，要让所有线程的这个操作都加到一个queue中
dispatch_sync(queue, ^{
NSInteger ticket = lastTicket;
[NSThread sleepForTimeInterval:0.1];
NSLog(@"%ld - %@",ticket, [NSThread currentThread]);
ticket -= 1;
lastTicket = ticket;
});

//NSOperation & NSOperationQueue
//重点：1. 全局的 NSOperationQueue, 所有的操作添加到同一个queue中
//       2. 设置 queue 的 maxConcurrentOperationCount 为 1
//       3. 如果后续操作需要Block中的结果，就需要调用每个操作的waitUntilFinished，阻塞当前线程，一直等到当前操作完成，才允许执行后面的。waitUntilFinished 要在添加到队列之后！

NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
NSInteger ticket = lastTicket;
[NSThread sleepForTimeInterval:1];
NSLog(@"%ld - %@",ticket, [NSThread currentThread]);
ticket -= 1;
lastTicket = ticket;
}];

[queue addOperation:operation];

[operation waitUntilFinished];

//后续要做的事

延迟执行

// 3秒后自动调用self的run:方法，并且传递参数：@"abc"
[self performSelector:@selector(run:) withObject:@"abc" afterDelay:3];

之前就已经说过，Swift 里去掉了这个方法。

dispatch_after

// 创建队列
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
// 设置延时，单位秒
double delay = 3;

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay * NSEC_PER_SEC)), queue, ^{
// 3秒后需要执行的任务
});

[NSTimer scheduledTimerWithTimeInterval:3.0 target:self selector:@selector(run:) userInfo:@"abc" repeats:NO];

单例模式

@interface Tool : NSObject <NSCopying>

+ (instancetype)sharedTool;

@end

@implementation Tool

static id _instance;

+ (instancetype)sharedTool {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_instance = [[Tool alloc] init];
});

return _instance;
}

@end

dispatch_once

class Tool: NSObject {
static let sharedTool = Tool()

// 私有化构造方法，阻止其他对象使用这个类的默认的'()'构造方法
private override init() {}
}

从其他线程回到主线程的方法

//Objective-C
[self performSelectorOnMainThread:@selector(run) withObject:nil waitUntilDone:NO];

//Swift
//swift 取消了 performSelector 方法。

//Objective-C
dispatch_async(dispatch_get_main_queue(), ^{

});

//Swift
dispatch_async(dispatch_get_main_queue(), { () -> Void in

})

//Objective-C
[[NSOperationQueue mainQueue] addOperationWithBlock:^{

}];

//Swift
NSOperationQueue.mainQueue().addOperationWithBlock { () -> Void in

}

总结