录音波形图的实现
在项目中我们需要实现一个动画特效，就是根据录音的分贝数来显示动画，线条长度代表分贝数，线条左右位置，逐渐变淡来代表时间，话不多说，下面介绍代码
1.创建一个视图view的子类：RecordWaveView
一个数组属性：waves，用来存储分贝数据
一个方法：-(void)setRecordWaveWithDecibel:(CGFloat)decibel,用来传入分贝数据，显示动画
初始化视图
-(instancetype)initWithFrame:(CGRect)frame{
if(self=[super initWithFrame:frame]){
self.backgroundColor=[UIColor clearColor];
}
return self;
}
画动画图，设置一个数组waves，waves中存储的是分贝数，然后将数组画在试图上：
-(void)drawRect:(CGRect)rect{
CGFloat w=self.frame.size.width/2;
CGFloat h=self.frame.size.height;
{
CGFloat n=[self.waves[i] floatValue];
UIBezierPath*linePath=[UIBezierPath bezierPath];
[linePath moveToPoint:SPPoint(w-30-i*5, (h-n)/2)];
[linePath addLineToPoint:SPPoint(w-30-i*5, (h+n)/2)];
linePath.lineWidth=2;
[[UIColor colorWithRed:250/255.0 green:127/255.0 blue:0/255.0 alpha:1-i/10.0f] setStroke];
[linePath stroke];
}循环块：0-self.waves.count的循环；
{
CGFloat n=[self.waves[i] floatValue];
UIBezierPath*linePath=[UIBezierPath bezierPath];
[linePath moveToPoint:SPPoint(w+30+i*5, (h-n)/2)];
[linePath addLineToPoint:SPPoint(w+30+i*5, (h+n)/2)];
linePath.lineWidth=2;
[[UIColor colorWithRed:250/255.0 green:127/255.0 blue:0/255.0 alpha:1-i/10.0f] setStroke];
[linePath stroke];
}循环块：0-self.waves.count的循环；
}
实现方法，让画的视图动起来
-(void)setRecordWaveWithDecibel:(CGFloat)decibel{
if(self.waves.count<10){
[self.waves insertObject:[NSNumber numberWithFloat:decibel] atIndex:0];
}
else{
[self.waves removeLastObject];
[self.waves insertObject:[NSNumber numberWithFloat:decibel] atIndex:0];
}
[self setNeedsDisplay];
}