IOS开发（61）之GCD执行非UI的操作

来源：互联网发布：园林绿化图软件编辑：程序博客网时间：2024/05/22 03:04

1 前言

当执行那些与 UI 无关的任务,或者与 UI 交互的任务时,和执行其他任务一样,会需要大量时间,以上情况会经常出现。我们可以使用 dispatch_sync函数在一个分派队列上执行同步任务。你必须做的事情就是提供一个此队列的句柄了,这个队列必须运行任务,并且一个代码块会在这个队列上执行。今天我们就来学习一下GCD执行非UI的操作。

2 代码实例

TestDemo.h

#import <Foundation/Foundation.h>@interface TestDemo : NSObject-(void)testMethod;-(void)testMethod2;@end

TestDemo.m

#import "TestDemo.h"@implementation TestDemo/**************Objc Method Start*********///Block Objectvoid (^printFrom1To1000)(void) = ^{    NSUInteger counter = 0;    for (counter = 1;counter <= 1000;counter++){    NSLog(@"Counter = %lu - Thread = %@",          (unsigned long)counter,          [NSThread currentThread]);    }};//测试方法-(void)testMethod{    /*     Dispatch_get_global_queue 函数的第一个参数说明了并发队列的优先级,这个属性 GCD 必须替程序员检     索。优先级越高,将提供更多的 CPU Timeslice 来获取该队列执行的代码。     Dispatch_get_global_queue 函数的第一个参数:      DISPATCH_QUEUE_PRIORITY_LOW     您的任务比正常任务用到更少的 Timeslice。      DISPATCH_QUEUE_PRIORITY_DEFAULT     执行代码的默认系统优先级将应用于您的任务。     DISPATCH_QUEUE_PRIORITY_HIGH     和正常任务相比,更多的 Timeslices 会应用到你的任务中。     Dispatch_get_global_queue 函数的第二个参数已经保存了,只要一直给它输入数值 0 就可以了。     */    dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);    dispatch_sync(concurrentQueue, printFrom1To1000);    dispatch_sync(concurrentQueue, printFrom1To1000);}/**************Objc Method End*********//**************C Method Start*********///Block Objectvoid print2From1To1000(void *paramContext){    NSUInteger counter = 0; for (counter = 1;counter <= 1000;counter++){        NSLog(@"Counter = %lu - Thread = %@",        (unsigned long)counter, [NSThread currentThread]);    }}//测试方法-(void)testMethod2{    /*          */    dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);    dispatch_sync_f(concurrentQueue, NULL,print2From1To1000);    dispatch_sync_f(concurrentQueue, NULL,print2From1To1000);}/**************C Method End*********/@end

main.m

#import <Foundation/Foundation.h>#import "TestDemo.h"int main(int argc, const char * argv[]){    @autoreleasepool {                TestDemo *test = [[TestDemo alloc] init];//        [test testMethod];        [test testMethod2];        [test release];            }    return 0;}

运行结果

2013-05-10 13:50:37.361 GCDExecuteNonUITest[556:303] Counter = 1 - Thread = <NSThread: 0x10010b2c0>{name = (null), num = 1}

2013-05-10 13:50:37.363 GCDExecuteNonUITest[556:303] Counter = 2 - Thread = <NSThread: 0x10010b2c0>{name = (null), num = 1}

...

2013-05-10 13:50:38.255 GCDExecuteNonUITest[556:303] Counter = 1 - Thread = <NSThread: 0x10010b2c0>{name = (null), num = 1}

2013-05-10 13:50:38.256 GCDExecuteNonUITest[556:303] Counter = 2 - Thread = <NSThread: 0x10010b2c0>{name = (null), num = 1}

...

3 结语

以上就是所有内容，希望对大家有所帮助。

Demo代码下载：http://download.csdn.net/detail/u010013695/5352720