我是自定義封裝了view, 用起來比較方便:
詳細(xì)代碼如下: (包括.h和.m文件)

// .h文件
#import <UIKit/UIKit.h>

@interface LineChartView : UIView

@property (nonatomic, strong) NSArray *titleForYArr;

@property (nonatomic, strong) NSArray *titleForXArr;

@property (nonatomic, strong) NSArray *valueArr;

@property (nonatomic, strong) UIColor *lineColor;

- (instancetype)initWithFrame:(CGRect)frame;

- (void)startDraw;

@end

// .m文件
#import "LineChartView.h"

@interface LineChartView()<CAAnimationDelegate>

@property (nonatomic, strong) CAShapeLayer *lineChartLayer;

@end

@implementation LineChartView {
    CGFloat width;
    CGFloat height;
}

static CGFloat edgeLeft = 30;
static CGFloat edgeRight = 20;
static CGFloat bounceY = 40;

static CGFloat edgeUp = 50;
static CGFloat edgeDown = 30;

- (instancetype)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        
        self.backgroundColor = [UIColor lightGrayColor];
        
        width = frame.size.width - edgeLeft - edgeRight;
        height = frame.size.height - edgeUp - edgeDown;
    }
    return self;
}
// 畫出坐標(biāo)軸
- (void)drawRect:(CGRect)rect {
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, 1.0);
    CGContextSetRGBStrokeColor(context, 0.6, 0.6, 0.6, 1);
    CGContextMoveToPoint(context, edgeLeft, edgeUp);
    CGContextAddLineToPoint(context, edgeLeft, edgeUp + height);
    CGContextAddLineToPoint(context,edgeLeft + width, edgeUp + height);
    CGContextStrokePath(context);
}


#pragma mark 畫折線圖
- (void)dravLine{

    NSInteger yearNum = self.titleForXArr.count;
    if (yearNum <= 0) {
        return;
    }
    CGFloat widthForX = width / yearNum;
    CGFloat maxValue = [[self.titleForYArr lastObject] floatValue];
    
    if (maxValue <= 0) {
        return;
    }
    
    UIBezierPath *pathLine = [[UIBezierPath alloc] init];
    [pathLine moveToPoint:CGPointMake(edgeLeft + widthForX * 0.5, ((maxValue - [self.valueArr[0] floatValue]) / maxValue) * height + edgeUp)];
    
    // 創(chuàng)建折線點(diǎn)標(biāo)記
    for (NSInteger i = 1; i < self.valueArr.count; i++) {
        
        CGPoint pointCenter = CGPointMake(edgeLeft + widthForX * (i + 0.5), (maxValue - [self.valueArr[i] floatValue]) / maxValue * height + edgeUp);
        
        UIImageView *pointImg = [[UIImageView alloc] init];
        pointImg.bounds = CGRectMake(0, 0, 5, 5);
        pointImg.center = pointCenter;
        pointImg.backgroundColor = _lineColor;
        [self addSubview:pointImg];
        
        [pathLine addLineToPoint:pointCenter];
    }
    
    CAShapeLayer  *lineChartLayer = [CAShapeLayer layer];
    lineChartLayer.path = pathLine.CGPath;
    lineChartLayer.strokeColor = _lineColor.CGColor;
    lineChartLayer.fillColor = [[UIColor clearColor] CGColor];
    lineChartLayer.lineWidth = 2.0;
    lineChartLayer.lineCap = kCALineCapRound;
    lineChartLayer.lineJoin = kCALineJoinRound;
    
    [self.layer addSublayer:lineChartLayer];
}

#pragma mark 創(chuàng)建x軸的數(shù)據(jù)
- (void)setTitleForXArr:(NSArray *)titleForXArr {
    _titleForXArr = titleForXArr;
    [self createLabelX];
}
- (void)createLabelX{

    NSInteger yearNum = self.titleForXArr.count;
    if (yearNum <= 0) {
        return;
    }
    CGFloat widthForX = width / yearNum;
    
    for (NSInteger i = 0; i < yearNum; i++) {
        
        UILabel *labelYear = [[UILabel alloc] initWithFrame:CGRectMake(edgeLeft + widthForX * i, height + edgeUp, widthForX, edgeDown)];
        labelYear.tag = 1000 + i;
        labelYear.text = self.titleForXArr[i];
        labelYear.font = [UIFont systemFontOfSize:14];
        labelYear.textAlignment = NSTextAlignmentCenter;
        [self addSubview:labelYear];
    }
}
#pragma mark 創(chuàng)建y軸數(shù)據(jù)及虛線
- (void)setTitleForYArr:(NSArray *)titleForYArr {
    _titleForYArr = titleForYArr;
    [self createLabelY];
    [self setLineDash];
}
- (void)createLabelY{

    NSInteger numForY = _titleForYArr.count;
    if (numForY <= 1) {
        return;
    }
    CGFloat widthForY = edgeLeft;
    CGFloat heightForY = height / (numForY - 1);
    
    for (NSInteger i = 0; i < numForY; i++) {
        
        UILabel *labelForY = [[UILabel alloc] initWithFrame:CGRectMake(0, edgeUp + (i - 0.5) * heightForY, widthForY, heightForY)];
        
        labelForY.tag = 2000 + i;
        labelForY.text = _titleForYArr[numForY - i - 1];
        labelForY.font = [UIFont systemFontOfSize:12];
        labelForY.textAlignment = NSTextAlignmentCenter;
        [self addSubview:labelForY];
    }
}
#pragma mark - 添加虛線
- (void)setLineDash {
    
    NSInteger numForY = _titleForYArr.count - 1;
    if (numForY <= 0) {
        return;
    }
    CGFloat heightForY = height / numForY;
    
    for (NSInteger i = 0; i < numForY; i++) {
        
        CAShapeLayer *dashLayer = [CAShapeLayer layer];
        dashLayer.strokeColor = [UIColor colorWithRed:0.6 green:0.6 blue:0.6 alpha:1].CGColor;
        dashLayer.lineWidth = 1.0;
        
        UIBezierPath *path = [[UIBezierPath alloc] init];
        path.lineWidth = 1.0;
        
        [path moveToPoint:CGPointMake(edgeLeft, edgeUp + i * heightForY)];
        [path addLineToPoint:CGPointMake(edgeLeft + width, edgeUp + i * heightForY)];
        CGFloat dash[] = {10,10};
        [path setLineDash:dash count:2 phase:10];
        [path stroke];
        dashLayer.path = path.CGPath;
        [self.layer addSublayer:dashLayer];
    }
}
#pragma mark - 開始畫折線
- (void)startDraw {
    [self dravLine];
}

@end


// 使用方法
- (void)viewDidLoad {
    [super viewDidLoad];
    
    LineChartView *lineView = [[LineChartView alloc] initWithFrame:CGRectMake(0, 100, self.view.bounds.size.width, 190)];
    
    lineView.titleForYArr = @[@"0",@"1",@"2",@"3",@"4",@"5"];
    lineView.titleForXArr = @[@"2013年",@"2014年",@"2015年",@"2016年",@"2017年"];
    lineView.lineColor = [UIColor redColor];
    lineView.valueArr = @[@"0.8",@"1.9",@"4.0",@"1.3",@"2.5"];
    
    [self.view addSubview:lineView];
    
    [lineView startDraw];
}