Sto creando un programma che può, tra l'altro, dissolvere la musica. Il problema è che altri thread/code possono mettere in pausa la musica, il che significa che anche la dissolvenza in entrata e in uscita non deve solo mettere in pausa, ma tenere a bada. Devo essere in grado di mettere in pausa il "timer" su un dispatch_after (perché questo viene chiamato quando la musica inizia a suonare per dire quando iniziare a dissolvere, che dovrebbe essere ritardato se era in pausa) e mettere in pausa una coda stesso (al fine di mettere in pausa un fade in o fade out mentre sono in dissolvenza dentro o fuori)Come mettere in pausa un dispatch_queue_t e le code create da esso
Ecco il codice (fadeIn e delayFadeOut sono entrambi chiamati all'inizio del programma):
- (void) doFadeIn: (float) incriment to: (int) volume with: (AVAudioPlayer*) thisplayer on: (dispatch_queue_t) queue{
dispatch_async(queue, ^{
double delayInSeconds = .1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, queue, ^(void){
thisplayer.volume = (thisplayer.volume + incriment) < volume ? thisplayer.volume + incriment : volume;
NSLog([[[NSNumber alloc] initWithFloat:thisplayer.volume] stringValue]);
if (thisplayer.volume < volume) {
[self doFadeIn:incriment to:volume with:thisplayer on:queue];
}
});
});
}
-(void) doDelayFadeOut: (float) incriment with: (AVAudioPlayer*) thisplayer on: (dispatch_queue_t) queue
{
dispatch_async(queue, ^{
double delayInSeconds = .1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, queue, ^(void){
thisplayer.volume = (thisplayer.volume - incriment) > 0 ? thisplayer.volume - incriment : 0;
NSLog([[[NSNumber alloc] initWithFloat:thisplayer.volume] stringValue]);
if (thisplayer.volume > 0.0) {
[self doDelayFadeOut:incriment with:thisplayer on:queue];
}
});
});
}
-(void) fadeIn: (AVAudioPlayer*) dFade {
if (dFade == nil) {
return;
}
dispatch_queue_t queue = dispatch_queue_create("com.cue.MainFade", NULL);
dispatch_async(queue, ^(void){
if(dFade !=nil){
double incriment = ([self relativeVolume]/[self fadeIn])/10; //incriment per .1 seconds.
[self doFadeIn: incriment to: [self relativeVolume] with:dFade on:dispatch_queue_create("com.cue.MainFade", 0)];
}
});
}
- (void) delayFadeOut: (AVAudioPlayer*) dFade { //d-fade should be independent of other threads
if (dFade == nil) {
return;
}
int timeRun = self.duration - self.fadeOut;
dispatch_queue_t queue = dispatch_queue_create("com.cue.MainFade", NULL);
dispatch_time_t mainPopTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(timeRun * NSEC_PER_SEC));
printf("test");
dispatch_after(mainPopTime, queue, ^(void){
if(dFade !=nil){
double incriment = ([dFade volume]/[self fadeOut])/10; //incriment per .1 seconds.
[self doDelayFadeOut:incriment with:dFade on:dispatch_queue_create("com.cue.MainFade", 0)];
}
});
if (self.cueType == 2) {
[self callNext];
}
}