基于音量级反馈的UIImageView动画

Question

我需要创建一个带有自定义模式的音频级可视化工具.我将图像设置为png.我目前的做法是这样的

1)获取麦克风的音频电平

2)根据音量级别将相关图像加载到UIImageView.

// audio level timer
self.levelTimer = [NSTimer scheduledTimerWithTimeInterval: 0.001 target: self selector: @selector(levelTimerCallback:) userInfo: nil repeats: YES];

ImageView的

- (void)levelTimerCallback:(NSTimer *)timer {
[self.audioRecorder updateMeters];
const double ALPHA = 0.05;
double peakPowerForChannel = pow(10, (0.05 * [self.audioRecorder peakPowerForChannel:0]));
lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults;

//NSLog(@"Average input: %f Peak input: %f Low pass results: %f", [self.audioRecorder averagePowerForChannel:0], [self.audioRecorder peakPowerForChannel:0], lowPassResults);

if (lowPassResults > 0.0 && lowPassResults <= 0.05){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim1"];
}
if (lowPassResults > 0.06 && lowPassResults <= 0.10){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim2"];
}
if (lowPassResults > 0.11 && lowPassResults <= 0.15){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim3"];
}
if (lowPassResults > 0.16 && lowPassResults <= 0.20){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim4"];
}
if (lowPassResults > 0.21 && lowPassResults <= 0.25){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim5"];
}
if (lowPassResults > 0.26 && lowPassResults <= 0.30){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim6"];
}
if (lowPassResults > 0.31 && lowPassResults <= 0.35){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim7"];
}
if (lowPassResults > 0.36 && lowPassResults <= 0.40){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim8"];
}
if (lowPassResults > 0.41 && lowPassResults <= 0.45){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim9"];
}
if (lowPassResults > 0.46 && lowPassResults <= 0.50){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim10"];
}
if (lowPassResults > 0.51 && lowPassResults <= 0.55){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim11"];
}
if (lowPassResults > 0.56 && lowPassResults <= 0.60){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim12"];
}
if (lowPassResults > 0.61 && lowPassResults <= 0.65){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim13"];
}
if (lowPassResults > 0.66 && lowPassResults <= 0.70){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim14"];
}
if (lowPassResults > 0.71 && lowPassResults <= 0.75){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim15"];
}
if (lowPassResults > 0.76 && lowPassResults <= 0.80){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim16"];
}
if (lowPassResults > 0.81 && lowPassResults <= 0.85){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim17"];
}
if (lowPassResults > 0.86 && lowPassResults <= 0.90){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim18"];
}
if (lowPassResults > 0.86){
    imgViewRecordAnimation.image = nil;
    imgViewRecordAnimation.image = [UIImage imageNamed:@"anim19"];
}

}

但输出并不是一个真正的可视化动画.什么应该是最好的方法？分享那里有更好的方法来做到这一点.

几个图像

Answer 1

如果您觉得图像变化看起来很不稳定，您最好对其应用动画。顺便说一句，您不需要设置nil为imgViewRecordAnimation.image，因为您每次都在设置正确的图像，这会引入不必要的延迟。您还可以将所有 if 语句改为 else if，否则每次都会执行所有 if 语句。

谈到解决方案，您只需点击@MileAtNobel 发布的链接即可。或者，如果您不想进行太多代码更改，您可以在backgroundColor属性上应用简单的动画。您也可以删除计时器，检查下面的代码并查看代码是否正常工作。我还尝试优化非常相似的代码，我希望这可以提高性能。

BOOL flagToContinue ; //assign NO to this flag to stop updating the images

-(void)levelTimerCallback
{
    NSLog(@"Volume Logic Begins") ;//Volume level logic begins
    [self.audioRecorder updateMeters];
    const double ALPHA = 0.05;
    double peakPowerForChannel = pow(10, (0.05 * [self.audioRecorder peakPowerForChannel:0]));
    lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults ;
    NSLog(@"Volume Logic ends") ;//Volume level logic ends

    [UIView animateWithDuration:0.001f
              delay:0.0f
            options: UIViewAnimationOptionCurveLinear
         animations:^{
           mgViewRecordAnimation.backgroundColor = [UIColor colorWithPatternImage:[NSString stringWithFormat:@"anim%d", (int)ceil(lowPassResults * 20)]];
         }
         completion:^(BOOL finished) {
           if(finished && flagToContinue) [self levelTimerCallback];
    }];
}