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iOS-一个带可滑动指针的折线图(类似微信指数小程序)

iOS-一个带可滑动指针的折线图(类似微信指数小程序)

作者: Hedgehog___ | 来源:发表于2018-05-04 17:59 被阅读281次
      在开发工作中,产品同学要求下个版本要做个数据统计的功能,其中需要显示图表(我们产品同学借鉴的是微信指数的折线图形式),于是为了应付接下来的开发工作,我便写了个小demo,在这里记录下来供大家参考讨论。最终运行效果如下: QQ20180504-172328-HD.gif

      水印请忽略,谁让我穷呢。
      废话不多说开始上代码了。首先创建一个chartView

    @interface CYXLineChartView : UIView
    /*y值列表*/
    @property (nonatomic,strong) NSArray *yValues;
    /*画线开始*/
    -(void)drawChartWithMaxYValue:(CGFloat)maxYValue;
    @end
    

    定义一个画线的方法,根据最大值画线实现为:

    -(void)drawChartWithMaxYValue:(CGFloat)maxYValue{
        if (maxYValue<=0||[self.yValues count]==0) {
            return;
        }
        _maxYValue = maxYValue;
        NSArray *layers = [self.layer.sublayers mutableCopy];
        for (CAShapeLayer *layer in layers) {
            [layer removeFromSuperlayer];
        }
        
        //画三条线
        [self drawXYLine];
        //添加y轴三个label
        [self drawYLabelsWithMaxYValue:maxYValue];
        //画X轴刻度和label
        [self drawXLineAndLabels];
        //画折线
        [self drawLine];
        [self addSubview:self.pointerView];
        [self addSubview:self.explainLabel];
    }
    

    首先先画三条线:

    - (void)drawXYLine{
        
        UIBezierPath *path = [UIBezierPath bezierPath];
        //y单位坐标距离
        CGFloat yUnitDistance = (CGRectGetHeight(myFrame)-kDrawMarginTop-kDrawMarginBottom)/(yCount-1);
        //从上到下
        for (int i =0; i<yCount; i++) {
            [path moveToPoint:CGPointMake(kDrawMarginLeft, yUnitDistance*i+kDrawMarginTop)];
            [path addLineToPoint:CGPointMake(CGRectGetWidth(myFrame)-kDrawMarginRight, yUnitDistance*i+kDrawMarginTop)];
        }
    
        CAShapeLayer *layer = [[CAShapeLayer alloc] init];
        layer.path = path.CGPath;
        layer.strokeColor = [UIColor brownColor].CGColor;
        layer.fillColor = [UIColor clearColor].CGColor;
        layer.lineWidth = 0.5;
        [self.layer addSublayer:layer];
        self.pointerView.frame = CGRectMake(0, kDrawMarginTop, 20, CGRectGetHeight(myFrame)-kDrawMarginTop-kDrawMarginBottom+10);
    }
    

    再画y显示Label

    -(void)drawYLabelsWithMaxYValue:(CGFloat)maxYValue{
        
        NSMutableArray * yValueList= [NSMutableArray new];
        //y值平均
        CGFloat yUnitValue = maxYValue/(yCount-1);
        for (int i=yCount-1; i>=0; i--) {
            [yValueList addObject:@(i*yUnitValue)];
        }
        CGFloat yUnitDistance = (CGRectGetHeight(myFrame)-kDrawMarginTop-kDrawMarginBottom)/(yCount-1);
        for (int i =0; i<yCount; i++) {
            UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, yUnitDistance*i+kDrawMarginTop, kDrawMarginLeft, 12)];
            label.centerY = yUnitDistance*i+kDrawMarginTop;
            label.textColor = [UIColor grayColor];
            label.font = [UIFont systemFontOfSize:12];
            //lbl.backgroundColor = [UIColor brownColor];
            label.textAlignment = NSTextAlignmentCenter;
            CGFloat yValue = [yValueList[i] floatValue];
            NSInteger yK = yValue/1000;
            label.text = [NSString stringWithFormat:@"%ldK",yK];
            [self addSubview:label];
        }
    }
    

    接下来画X轴刻度和显示Label

    -(void)drawXLineAndLabels{
        //先计算当前月份和当前月的总天数
        [self setCurrentDaysAndMoth];
        
        NSLog(@"%02ld",_currentMonth);
        NSLog(@"%02ld",_currentMonthTotalDays);
        UIBezierPath *path = [UIBezierPath bezierPath];
        CGFloat  xUnitValue = 10;
        CGFloat  xTotalDistance = CGRectGetWidth(myFrame)-kZeroMarginLeft-kZeroMarginRight;
        CGFloat  xUnitMargin = xUnitValue/_currentMonthTotalDays *xTotalDistance;
        
        NSInteger day = 1;
        CGFloat centerX;
        for (int i=0; i<xCount; i++) {
            if (i==xCount-2) {//倒数第二个刻度
                [path moveToPoint:CGPointMake(kZeroMarginLeft+xTotalDistance-xUnitMargin, CGRectGetHeight(myFrame)-kDrawMarginBottom)];
                [path addLineToPoint:CGPointMake(kZeroMarginLeft+xTotalDistance-xUnitMargin, CGRectGetHeight(myFrame)-kDrawMarginBottom+8)];
                day = _currentMonthTotalDays-10+1;
                centerX = kZeroMarginLeft+xTotalDistance-xUnitMargin;
            }else if (i==xCount-1){//倒数第一个刻度
                [path moveToPoint:CGPointMake(kZeroMarginLeft+xTotalDistance, CGRectGetHeight(myFrame)-kDrawMarginBottom)];
                [path addLineToPoint:CGPointMake(kZeroMarginLeft+xTotalDistance, CGRectGetHeight(myFrame)-kDrawMarginBottom+8)];
                day = _currentMonthTotalDays;
                centerX = kZeroMarginLeft+xTotalDistance;
            }else{//其余刻度
                [path moveToPoint:CGPointMake(kZeroMarginLeft+i*xUnitMargin, CGRectGetHeight(myFrame)-kDrawMarginBottom)];
                [path addLineToPoint:CGPointMake(kZeroMarginLeft+i*xUnitMargin, CGRectGetHeight(myFrame)-kDrawMarginBottom+8)];
                if (i==0) {
                    day = 1;
                }else{
                  day = day+xUnitValue*i-1;
                }
                centerX = kZeroMarginLeft+i*xUnitMargin;
            }
            UILabel *label = [[UILabel alloc] init];
            label.textColor = [UIColor grayColor];
            label.font = [UIFont systemFontOfSize:12];
            label.textAlignment = NSTextAlignmentCenter;
            label.text = [NSString stringWithFormat:@"%02ld-%02ld",_currentMonth,day];
            [label sizeToFit];
            label.centerX = centerX;
            label.bottom = CGRectGetHeight(myFrame)-10;
            [self addSubview:label];
        }
        CAShapeLayer *layer = [[CAShapeLayer alloc] init];
        layer.path = path.CGPath;
        layer.strokeColor = [UIColor brownColor].CGColor;
        layer.fillColor = [UIColor clearColor].CGColor;
        layer.lineWidth = 0.5;
        [self.layer addSublayer:layer];
    }
    

    再画折线

    -(void)drawLine{
        if ([self.yValues count]>_currentMonthTotalDays) {
            NSLog(@"******************数据和当前月份不一致******************");
            return;
        }
        _pointList = [NSMutableArray new];
        UIBezierPath *path = [UIBezierPath bezierPath];
        
        CGFloat yTotalDistance =CGRectGetHeight(myFrame)-kDrawMarginBottom-kDrawMarginTop;
        CGFloat firstY = [[self.yValues firstObject] floatValue];
        CGPoint firstPoint =CGPointMake(kZeroMarginLeft, yTotalDistance - (firstY/_maxYValue*yTotalDistance)+kDrawMarginTop);
        [path moveToPoint:firstPoint];
        [_pointList addObject:[NSValue valueWithCGPoint:firstPoint]];
        
        CGFloat  xTotalDistance = CGRectGetWidth(myFrame)-kZeroMarginLeft-kZeroMarginRight;
        CGFloat  xUnitMargin = xTotalDistance/(_currentMonthTotalDays-1);
        for (int i =1; i<[self.yValues count]; i++) {
            CGFloat yValue =[self.yValues[i] floatValue];
            CGPoint point = CGPointMake(kZeroMarginLeft+xUnitMargin*i, yTotalDistance - (yValue/_maxYValue*yTotalDistance)+kDrawMarginTop);
            [path addLineToPoint:point];
            if (i == [self.yValues count]-1) {//刻度尺默认选择当前 日期
                self.pointerView.centerX =point.x;
                self.pointerView.maxX = point.x-self.pointerView.width/2;
            }
            [_pointList addObject:[NSValue valueWithCGPoint:point]];
        }
        [self changeExplainLabelWithCenterX:self.pointerView.centerX];
        self.pointerView.minX = kZeroMarginLeft-self.pointerView.width/2;
        self.explainLabel.top =27;
        CAShapeLayer *layer = [[CAShapeLayer alloc] init];
        layer.path = path.CGPath;
        layer.strokeColor = [UIColor redColor].CGColor;
        layer.fillColor = [UIColor clearColor].CGColor;
        layer.lineWidth = 1;
        
        CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
        pathAnimation.duration = 1.5;
        pathAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
        pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
        pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
        pathAnimation.autoreverses = NO;
        
        [layer addAnimation:pathAnimation forKey:@"lineLayerAnimation"];
        layer.strokeEnd = 1.0;
        [self.layer addSublayer:layer];
    }
    

    最后就是解决游标问题了,创建一个游标View

    @interface CYXPointerView : UIView
    /*最小x*/
    @property (nonatomic,assign) CGFloat minX;
    /*最小x*/
    @property (nonatomic,assign) CGFloat maxX;
    /*当指针centerx发生变化的时候*/
    @property (nonatomic,strong) void(^centerXChanged)(CGFloat centerX);
    @end
    

    游标拖拽问题,我们在-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event方法中实现

    -(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
        NSLog(@"手指移动");
        //实现拖动
        //获取touch
        UITouch * touch = [touches anyObject];
        //获取当前点
        CGPoint curretPoint = [touch locationInView:self];
        //获取上一个点
        CGPoint prePoint = [touch previousLocationInView:self];
        //x变化
        CGFloat offsetX = curretPoint.x - prePoint.x;
        //y变化
        //CGFloat offsetY =curretPoint.y - prePoint.y;
        //相对于上一次位置的形变  make相对于原始位置
        CGPoint point = self.frame.origin;
        if (point.x+offsetX<=self.maxX&&point.x+offsetX>=self.minX) {
            //self.transform = CGAffineTransformTranslate(self.transform, offsetX, 0);
            self.left = self.left+offsetX;
        }else if (point.x+offsetX>self.maxX){
            self.left = self.maxX;
        }else if (point.x+offsetX<self.minX){
            self.left = self.minX;
        }
        self.centerXChanged(self.centerX);
    }
    

    点击图标游标的变动在CYXPointerView中实现

    -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
        //获取touch
        UITouch * touch = [touches anyObject];
        //获取当前点
        CGPoint curretPoint = [touch locationInView:self];
        NSLog(@"%f",curretPoint.x);
        if (curretPoint.x<=self.pointerView.maxX+self.pointerView.width/2&&curretPoint.x>=self.pointerView.minX+self.pointerView.width/2) {
            self.pointerView.centerX = curretPoint.x;
        }else if (curretPoint.x<=self.pointerView.maxX+self.pointerView.width/2){
            self.pointerView.left = self.pointerView.minX;
        }else if (curretPoint.x>=self.pointerView.minX+self.pointerView.width/2){
            self.pointerView.left = self.pointerView.maxX;
        }
        [self changeExplainLabelWithCenterX:self.pointerView.centerX];
    }
    

    最后解决游标显示Label显示方向的问题:

    -(void)changeExplainLabelWithCenterX:(CGFloat)centerX{
        if (centerX<CGRectGetWidth(myFrame)/2) {
            self.explainLabel.left = centerX+7;
        }else{
            self.explainLabel.right = centerX-7;
        }
        for (int i=0; i<[_pointList count]; i++) {
            NSValue * value =_pointList[i];
            CGPoint point = [value CGPointValue];
            NSLog(@"%d",i);
            if (point.x>centerX&&i>0) {
                CGFloat offsetxCurrent = point.x-centerX;
                NSValue * value2 =_pointList[i-1];
                CGPoint point2 = [value2 CGPointValue];
                CGFloat offsetxNext = centerX-point2.x;
                NSLog(@"centerX:%f",centerX);
                if (offsetxCurrent<=offsetxNext) {
                    NSLog(@"point:%f",point.x);
                    self.explainLabel.text = [NSString stringWithFormat:@"%@",self.yValues[i]];
                }else{
                    NSLog(@"point2:%f",point2.x);
                    self.explainLabel.text = [NSString stringWithFormat:@"%@",self.yValues[i-1]];
                }
                break;
            }else if (point.x==centerX){
                self.explainLabel.text = [NSString stringWithFormat:@"%@",self.yValues[i]];
            }
        }
    }
    

    这样就实现了上图功能了,有问题欢迎指教。
    最后付demo地址:https://github.com/SionChen/CYXLineChatDemo

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