在iOS的Charts库中实现chartValueSelected方法

Question

我有一个应用程序，可以使用iOS Charts库v.2.3显示包含数据的图表。现在我必须启用该选项来跟踪图表上的数据触摸点。我做了一些研究，我知道，我必须在类中使用chartValueSelected方法来实现。我还将chartView.delegate声明为self并在故事板上连接插座。但是当我测试它时，我总是从chartValueNothingSelected方法获得一个信号，没有来自chartValueSelected的信号。我应该在我的代码中添加一些内容，以便跟踪我的应用程序中的点的触摸？

编辑：代码

@interface ChartViewController () <ChartViewDelegate>

@end

@implementation ChartViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.chartView.delegate = self;
    _chartView.dragEnabled = YES;
    [_chartView setScaleEnabled:YES];
    _chartView.pinchZoomEnabled = YES;
    _chartView.drawGridBackgroundEnabled = NO;
    
    // some random data generator
    // x-axis limit line
    ChartLimitLine *llXAxis = [[ChartLimitLine alloc] initWithLimit:10.0 label:@"Index 10"];
    llXAxis.lineWidth = 4.0;
    llXAxis.lineDashLengths = @[@(10.f), @(10.f), @(0.f)];
    llXAxis.labelPosition = ChartLimitLabelPositionRightBottom;
    llXAxis.valueFont = [UIFont systemFontOfSize:10.f];
    
    //[_chartView.xAxis addLimitLine:llXAxis];
    
    _chartView.xAxis.gridLineDashLengths = @[@10.0, @10.0];
    _chartView.xAxis.gridLineDashPhase = 0.f;
    
    ChartLimitLine *ll1 = [[ChartLimitLine alloc] initWithLimit:150.0 label:@"Upper Limit"];
    ll1.lineWidth = 4.0;
    ll1.lineDashLengths = @[@5.f, @5.f];
    ll1.labelPosition = ChartLimitLabelPositionRightTop;
    ll1.valueFont = [UIFont systemFontOfSize:10.0];
    
    ChartLimitLine *ll2 = [[ChartLimitLine alloc] initWithLimit:-30.0 label:@"Lower Limit"];
    ll2.lineWidth = 4.0;
    ll2.lineDashLengths = @[@5.f, @5.f];
    ll2.labelPosition = ChartLimitLabelPositionRightBottom;
    ll2.valueFont = [UIFont systemFontOfSize:10.0];
    
    ChartYAxis *leftAxis = _chartView.leftAxis;
    [leftAxis removeAllLimitLines];
    [leftAxis addLimitLine:ll1];
    [leftAxis addLimitLine:ll2];
    leftAxis.gridLineDashLengths = @[@5.f, @5.f];
    leftAxis.drawZeroLineEnabled = NO;
    leftAxis.drawLimitLinesBehindDataEnabled = YES;
    
    _chartView.rightAxis.enabled = NO;
    
    //[_chartView.viewPortHandler setMaximumScaleY: 2.f];
    //[_chartView.viewPortHandler setMaximumScaleX: 2.f];
    

    //_chartView.marker = marker;
    
    _chartView.legend.form = ChartLegendFormLine;
    
    [_chartView animateWithXAxisDuration:2.5];
    
    NSMutableArray *xVals = [[NSMutableArray alloc] init];
    
    for (int i = 0; i < 100; i++)
    {
        [xVals addObject:[@(i) stringValue]];
    }
    
    NSMutableArray *yVals = [[NSMutableArray alloc] init];
    
    for (int i = 0; i < 100; i++)
    {
        double mult = (1000 + 1);
        double val = (double) (arc4random_uniform(mult)) + 3;
        [yVals addObject:[[ChartDataEntry alloc] initWithValue:val xIndex:i]];
    }
    
    LineChartDataSet *set1 = nil;
    if (_chartView.data.dataSetCount > 0)
    {
        set1 = (LineChartDataSet *)_chartView.data.dataSets[0];
        set1.yVals = yVals;
        _chartView.data.xValsObjc = xVals;
        [_chartView.data notifyDataChanged];
        [_chartView notifyDataSetChanged];
    }
    else
    {
        set1 = [[LineChartDataSet alloc] initWithYVals:yVals label:@"DataSet 1"];
        
        set1.lineDashLengths = @[@5.f, @2.5f];
        set1.highlightLineDashLengths = @[@5.f, @2.5f];
        [set1 setColor:UIColor.blackColor];
        [set1 setCircleColor:UIColor.blackColor];
        set1.lineWidth = 1.0;
        set1.circleRadius = 3.0;
        set1.drawCircleHoleEnabled = NO;
        set1.valueFont = [UIFont systemFontOfSize:9.f];
        //set1.fillAlpha = 65/255.0;
        //set1.fillColor = UIColor.blackColor;
        
        NSArray *gradientColors = @[
                                    (id)[ChartColorTemplates colorFromString:@"#00ff0000"].CGColor,
                                    (id)[ChartColorTemplates colorFromString:@"#ffff0000"].CGColor
                                    ];
        CGGradientRef gradient = CGGradientCreateWithColors(nil, (CFArrayRef)gradientColors, nil);
        
        set1.fillAlpha = 1.f;
        set1.fill = [ChartFill fillWithLinearGradient:gradient angle:90.f];
        set1.drawFilledEnabled = YES;
        
        CGGradientRelease(gradient);
        
        NSMutableArray *dataSets = [[NSMutableArray alloc] init];
        [dataSets addObject:set1];
        
        LineChartData *data = [[LineChartData alloc] initWithXVals:xVals dataSets:dataSets];
        
        _chartView.data = data;
    }
}

- (void)chartValueSelected:(ChartViewBase * __nonnull)chartView entry:(ChartDataEntry * __nonnull)entry highlight:(ChartHighlight * __nonnull)highlight
{
    NSLog(@"chartValueSelected");
}

- (void)chartValueNothingSelected:(ChartViewBase * __nonnull)chartView
{
    NSLog(@"chartValueNothingSelected");
}

@end

and from .h file

#import <UIKit/UIKit.h>
@import Charts;

@interface ChartViewController : UIViewController
@property(nonatomic, strong) IBOutlet LineChartView* chartView;
@property (strong, nonatomic) IBOutlet NSLayoutConstraint *chartViewHeightConstraint;

@end

Answer 1

对于每个人来说，谁会遇到与我类似的问题。我解决了我的问题，清理了一切，可以使用CocoaPods工具保留旧版2.3图表，之后添加对新3.0版本的引用。对我来说，它启用了显示实际点击点的选项。