所以你正在使用Charts https://github.com/danielgindi/Charts right?
你检查过 BallonMarker.swift 了吗?
/ChartsDemo/Classes/Components/BallonMarker.swift
Swift
let marker:BalloonMarker = BalloonMarker(color: UIColor.redColor(), font: UIFont(name: "Helvetica", size: 12)!, insets: UIEdgeInsets(top: 7.0, left: 7.0, bottom: 7.0, right: 7.0))
marker.minimumSize = CGSizeMake(75.0, 35.0)
chartView.marker = marker
斯威夫特 3 更新
let marker:BalloonMarker = BalloonMarker(color: UIColor.black, font: UIFont(name: "Helvetica", size: 12)!, textColor: UIColor.white, insets: UIEdgeInsets(top: 7.0, left: 7.0, bottom: 7.0, right: 7.0))
marker.minimumSize = CGSize(width: 75.0, height: 35.0)
chartView.marker = marker
Objective-C
BalloonMarker *marker = [[BalloonMarker alloc] initWithColor:[UIColor colorWithRed:14.0/255.0 alpha:1.0] font:[UIFont systemFontOfSize:12.0] insets: UIEdgeInsetsMake(7.0, 7.0, 7.0, 7.0)];
marker.minimumSize = CGSizeMake(75.f, 35.f);
_chartView.marker = marker;