// ViewController.m
#import "ViewController.h"
@interface ViewController ()
{
//任务队列，能够自动管理多个任务(NSOperation的对象)
NSOperationQueue *_operationQueue;
}
@end
@implementation ViewController
#define kUrlString @"http://jsonfe.funshion.com/?pagesize=10&cli=iphone&page=1&src=phonemedia&ta=0&ver=1.2.8.2&jk=0"
#define kImageString @"http://img1.funshion.com/attachment/fs/112/200/112200.jpg?1387939530"
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
_operationQueue = [[NSOperationQueue alloc] init];
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setTitle:@"thread" forState:UIControlStateNormal];
[btn setFrame:CGRectMake(10,30,300,50)];
[btn addTarget:self action:@selector(threadMethod) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];
UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn1 setTitle:@"operation" forState:UIControlStateNormal];
[btn1 setFrame:CGRectMake(10,90,300,50)];
[btn1 addTarget:self action:@selector(operationMethod) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn1];
UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn2 setTitle:@"GCD" forState:UIControlStateNormal];
[btn2 setFrame:CGRectMake(10,150,300,50)];
[btn2 addTarget:self action:@selector(gcdMethod) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn2];
/*严重的费时操作 等好久才能显示
for (int i=0; i<20; i++) {
for (int j=0; j<50; j++) {
NSURL *url =[NSURL URLWithString:kImageString];
//同步下载数据的方法
NSData *data = [NSData dataWithContentsOfURL:url];
// UIImage *ima = [UIImage imageWithData:data];
UIImageView *ima=[[UIImageView alloc]initWithFrame:CGRectMake(0+j*3, i*3, 2, 2)];
ima.image=[UIImage imageWithData:data];
[self.view addSubview:ima];
}
}
*/
}
//gcd是iOS4.0之后出现的技术,Grand Centeral Dispatch->苹果高度封装的处理多线程的技术,可以理解为block版本的NSOperation和NSOperationQueue
- (void)gcdMethod{
//gcd中有一个主队列，用于管理和调度主线程；有三个优先级的全局队列，来管理子线程
//dispatch_get_global_queue 第一个参数为设置队列的优先级 0为默认优先级 2为最高优先级 -1为低优先级;第二个参数为预留参数,一般也写成0
dispatch_async(dispatch_get_global_queue(0, 0), ^{
//利用全局队列，在主线程之外单独开辟了一个线程,线程执行block方法
NSURL *url =[NSURL URLWithString:kUrlString];
NSString *result = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
if (result) {
//通过主队列回到主线程，主线程中执行block
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(@"result:%@",result);
});
}else{
NSLog(@"error!");
}
});
}
//NSOperation,以任务为导向的线程,可以叫做开启一个任务
//NSOperationQueue 任务队列，来维护多个任务(线程)
- (void)operationMethod{
//一般使用NSOperation的子类来进行多线程操作
NSInvocationOperation *oper = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downloadImage) object:nil];
//[oper start]; 需要调用此方法 oper对象才会开辟线程，让线程执行sel方法
//添加到队列后，队列会自动让oper对象开辟线程并执行sel方法
[_operationQueue addOperation:oper];
//[_operationQueue addOperations:<#(NSArray *)#> waitUntilFinished:<#(BOOL)#>]
}
//NSThread
- (void)threadMethod{
//NSThread iOS中最早出现的线程类
//detachNewThreadSelector 在主线程之外单独开辟一个线程来执行sel方法
//toTarget sel所在的对象
[NSThread detachNewThreadSelector:@selector(downloadString) toTarget:self withObject:nil];
}
//同步下载一张图片
- (void)downloadImage{
@autoreleasepool {
NSURL *url =[NSURL URLWithString:kImageString];
//同步下载数据的方法
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if (image) {
//给主线程
[self performSelectorOnMainThread:@selector(receiveImage:) withObject:image waitUntilDone:NO];
//线程之间的通信
//[self performSelector:<#(SEL)#> onThread:<#(NSThread *)#> withObject:<#(id)#> waitUntilDone:<#(BOOL)#>]
}else{
NSLog(@"下载失败!");
}
}
}
- (void)receiveImage:(UIImage *)image{
//colorWithPatternImage 此方法比较消耗GPU，需要慎用,而且要求view与imagesize 一致
// self.view.backgroundColor = [UIColor colorWithPatternImage:image];
//多线程可以解决费时操作 比普通的下载图片快很多
for (int i=0; i<200; i++) {
for (int j=0; j<500; j++) {
UIImageView *ima=[[UIImageView alloc]init];
ima.frame=CGRectMake(0+j*30, i*30, 20, 20);
ima.image=image;
[self.view addSubview:ima];
}
}
}
//线程的生命周期与函数一致,函数开始则线程开始；函数执行完毕，线程自动结束
//在主线程之外开辟的线程叫子线程或者工作线程
- (void)downloadString{
//执行耗时操作
//主线程的自动释放池，子线程无法使用，需要自己手动添加
@autoreleasepool {
NSURL *url = [NSURL URLWithString:kUrlString];
//同步请求数据的方法，会阻塞当前线程
NSString *result = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
if (result) {
//需要将数据给到UI主线程,理论上子线程没有被分配足够的资源来操作UI，所以对于UI的操作一般在主线程中完成。
//子线程和主线程之间的通信
[self performSelectorOnMainThread:@selector(receiveString:) withObject:result waitUntilDone:NO];
//[self performSelector:<#(SEL)#> withObject:<#(id)#>]
}else{
NSLog(@"load error!");
}
}
}
//在主线程中执行的方法
- (void)receiveString:(NSString *)result{
NSLog(@"ui result:%@",result);
//操作UI也在主线程中
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
