iphone - 在 iOS 中创建一个连续的后台线程

Question

我需要创建一个仅在应用程序处于事件模式时才工作的后台处理器。我已尝试对我想要实现但无法实现的目标进行粗略描述。

我希望这个后台处理器在应用程序进入非事件阶段时进入休眠状态，并在应用程序进入事件模式时恢复。我在下面提供了我所做工作的框架。谁能帮我解决这个问题。

AppDelegate.h

#import <Foundation/Foundation.h>

@class BackgroundProcessor;

@interface AppDelegate_iPhone : UIResponder<UIApplicationDelegate>{
    BackgroundProcessor* processor;
}

@property(nonatomic) BackgroundProcessor *processor;

@end

AppDelegate.m

#import "AppDelegate_iPhone.h"
#import "BackgroundProcessor.h"


@implementation AppDelegate_iPhone

@synthesize processor;

-(BOOL) application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    processor = [[BackgroundProcessor alloc]init];
    [processor Start];         
    return YES;
}

-(void) applicationDidEnterBackground:(UIApplication *)application
{
    [processor Sleep];
    NSLog(@"Entered Background"); 
}

-(void) applicationDidBecomeActive:(UIApplication *)application
{
    [processor Resume];
    NSLog(@"Became Active"); 
}
@end

背景处理器.h

#import <Foundation/Foundation.h>

@interface BackgroundProcessor : NSObject
{
    NSThread* processor;
}

@property (nonatomic) NSThread *processor;

-(void) Start;
-(void) Sleep;
-(void) workloop;
-(void) Resume;
@end

背景处理器.m

#import "BackgroundProcessor.h"

@implementation BackgroundProcessor
@synthesize processor;
-(id) init
{
    self = [super init];
    if(self)
    {
        processor = [[NSThread alloc] initWithTarget:self selector:@selector(workloop) object:nil];
    }
    return self;
}

-(void) Start
{
    if(processor)
        [processor start];
}

-(void) Sleep
{
    //    [processor 
    [NSThread sleepForTimeInterval: 0.1];
}

-(void) workloop
{
    NSLog(@"Background Processor Processing ....");  
    [NSThread sleepForTimeInterval:0.1];
}

- (void) Resume
{
    NSLog(@"Background Resuming ....");  
    [NSThread sleepForTimeInterval: 0.1];
}

我无法让工作循环持续运行。感谢是否有人可以帮助我解决背景问题

在 Joshua Smith 的建议下尝试了这个

#import "BackgroundProcessor.h"

@implementation BackgroundProcessor

-(id) init
{
    self = [super init];
    if(self)
    {
        queue = [[NSOperationQueue alloc] init];
        NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(workloop) object:nil];
        [queue addOperation:operation];
    }
    return self;
}

-(void) workloop
{

    NSLog(@"Sleeping for 10 seconds");  
    sleep(10);
    NSLog(@"Background Processor Processing ....");  
    NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(workloop) object:nil];
    [queue addOperation:operation];
}

@end

Answer 1

除非有某些特定原因，这必须是一个离散线程，否则我建议您使用 GCD 或 NSOperation Queue 来生产和使用工作线程。这种长时间运行的线程将成为 iOS 应用程序中的一个真正问题。

GCD 教程:

http://www.raywenderlich.com/4295/multithreading-and-grand-central-dispatch-on-ios-for-beginners-tutorial