NSTimer没有调用Method

Question

我有一个NSTimer应该每秒调用一个方法,但它似乎根本没有调用它.

这就是我声明计时器的方式:

[NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(fadeManager:) userInfo:nil repeats:YES];

这是它调用的方法:

-(void) fadeManager: (NSTimer*) timer{
    NSLog(@"IT'S WORKING!");
    self.playHead += .1; // keeps track of where they are in full track
    if (self.playHead >= self.wait  && ![player isPlaying]) { // checks if wait is over
        [player play];
    }
    if (self.playHead >= self.duration + self.startTime && [player isPlaying]) { // checks if full duration is over
        [player pause];
        [self reset];
    }
    int fadeOutArea = self.startTime + self.duration - self.fadeOut;
    int fadeInArea = self.startTime + self.fadeIn;
    if (self.playHead <= fadeInArea && [player volume] < relativeVolume) { // checks if fadingIn.
        [self fadeInIncriment];
    }
    if (self.playHead >= fadeOutArea  && [player volume] > 0) {
        [self fadeOutIncriment];
    }
}

代码没有工作,所以我把NSLog和断点都放在了一起.似乎永远不会被召唤.为什么是这样？我在.m文件中声明方法是否重要:

#import <AVFoundation/AVFoundation.h>
@interface CueMusic ()

- (void) delayFadeOut: (AVAudioPlayer*) dFade;
- (void) fadeInIncriment;
- (void) fadeOutIncriment;
- (void) fadeManager: (NSTimer*) timer; // <--------
- (void) start;

@end

@implementation CueMusic
 .......

Answer 1

要么使用

NSTimer *timer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(fadeManager:) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];

要么

//schedules the timer
[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(fadeManager:) userInfo:nil repeats:YES];

从运行循环中的文档调度计时器

• 使用scheduledTimerWithTimeInterval:invocation:repeats:or scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:class方法创建计时器并在默认模式下在当前运行循环上计划它.

• 使用timerWithTimeInterval:invocation:repeats:or timerWithTimeInterval:target:selector:userInfo:repeats:class方法创建计时器对象,而不在运行循环上计划它.(创建它之后,必须通过调用相应NSRunLoop对象的addTimer:forMode:方法手动将计时器添加到运行循环中.)

SWIFT代码

或

let timer: NSTimer = NSTimer(timeInterval: 1.0, target: self, selector: "fadeManager:", userInfo: nil, repeats: true)
NSRunLoop.mainRunLoop().addTimer(timer, forMode: NSDefaultRunLoopMode)

要么

//schedules the timer
NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: "fadeManager:", userInfo: nil, repeats: true)

Answer 2

您的问题是,在使用时timerWithTimeInterval:target:selector:userInfo:repeats:,生成的计时器不会自动添加到运行循环中.我建议scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:改为使用,它会为您执行此步骤.

如果您更喜欢使用,timerWithTimeInterval:target:selector:userInfo:repeats:则需要手动将计时器添加到当前运行循环中.要做到这一点,调用NSRunLoop的addTimer:forMode:方法.文档

[[NSRunLoop currentRunLoop] addTimer:tTimer forMode: NSDefaultRunLoopMode];