配置速度计提醒

启用导航功能并将出行模式设置为驾车时，Navigation SDK for iOS 会在地图的左下角显示一个限速控件，其中会显示当前的限速。如果司机超速，控件会展开，在限速显示旁边显示速度计，并在速度达到一定阈值时触发提醒。

默认情况下，当驾驶员超速 5 英里/小时（或 10 公里/小时）时，导航 SDK 会触发轻微超速提醒，并将车速表文字颜色更改为红色。当驾驶员超速 10 英里/小时（或 20 公里/小时）时，系统会触发严重超速提醒，并将车速表背景颜色更改为红色。

您可以自定义触发提醒的阈值，以及速度表显示的文字和背景颜色。您还可以使用 Navigation SDK 来提供驾驶员的速度信息。例如，您可以向网约车运营商提供速度信息，帮助他们鼓励司机遵守限速规定，从而提高安全性。

自定义速度提醒的阈值

您可以自定义轻微超速和严重超速提醒的速度提醒阈值，以当前速度超过限速的百分比表示。您还可以指定在超出阈值多长时间后，地图显示提醒。

以下代码示例将轻微超速提醒的阈值设置为超速限制的 5%，并将严重超速提醒的阈值设置为超速限制的 10%。它指定了在超过提醒阈值 5 秒后，地图会显示提醒。

Swift

let minorSpeedAlertThresholdPercentage: CGFloat = 0.05 let
majorSpeedAlertThresholdPercentage: CGFloat = 0.1 let
severityUpgradeDurationSeconds: TimeInterval = 5

// Configure SpeedAlertOptions let mutableSpeedAlertOptions:
GMSNavigationMutableSpeedAlertOptions = GMSNavigationMutableSpeedAlertOptions()
 mutableSpeedAlertOptions.setSpeedAlertThresholdPercentage(minorSpeedAlertThresholdPercentage,
for: .minor)
mutableSpeedAlertOptions.setSpeedAlertThresholdPercentage(majorSpeedAlertThresholdPercentage,
for: .major) mutableSpeedAlertOptions.severityUpgradeDurationSeconds =
severityUpgradeDurationSeconds

// Set SpeedAlertOptions to Navigator. mapView.navigator?.speedAlertOptions =
mutableSpeedAlertOptions; mapView.navigator?.add(self); // Only needed if
listening to the delegate events.

Objective-C

static const CGFloat minorSpeedAlertThresholdPercentage = 0.05; static const
CGFloat majorSpeedAlertThresholdPercentage = 0.1; static const NSTimeInterval
severityUpgradeDurationSeconds = 5;

// Configure SpeedAlertOptions GMSNavigationMutableSpeedAlertOptions
*mutableSpeedAlertOptions = [[GMSNavigationMutableSpeedAlertOptions alloc]
init]; [mutableSpeedAlertOptions setSpeedAlertThresholdPercentage:
minorSpeedAlertThresholdPercentage
forSpeedAlertSeverity:GMSNavigationSpeedAlertSeverityMinor];
[mutableSpeedAlertOptions
setSpeedAlertThresholdPercentage:majorSpeedAlertThresholdPercentage
forSpeedAlertSeverity:GMSNavigationSpeedAlertSeverityMajor];
[mutableSpeedAlertOptions
setSeverityUpgradeDurationSeconds:severityUpgradeDurationSeconds];

// Set SpeedAlertOptions to Navigator. mapView.navigator.speedAlertOptions =
mutableSpeedAlertOptions; [mapView.navigator addListener:self]; // Only needed
if listening to the delegate events.

自定义速度计显示速度提醒的方式

您可以为每个提醒级别自定义速度表显示的颜色。

下表显示了 GMSNavigationSpeedometerUIOptions 类中速度提醒的默认颜色：

元素颜色
MinorSpeedAlertBackgroundColorDayMode 0xffffff（白色）
MinorSpeedAlertBackgroundColorNightMode 0x000000
MinorSpeedAlertTextColorDayMode 0xd93025
MinorSpeedAlertTextColorNightMode 0xd93025
MajorSpeedAlertBackgroundColorDayMode 0xd93025
MajorSpeedAlertBackgroundColorNightMode 0xd93025
MajorSpeedAlertTextColorDayMode 0xffffff（白色）
MajorSpeedAlertTextColorNightMode 0xffffff（白色）

您可以为次要和主要超速提醒指定速度表的文字和背景颜色：

Swift

let mutableSpeedometerUIOptions: GMSNavigationMutableSpeedometerUIOptions =
GMSNavigationMutableSpeedometerUIOptions()
mutableSpeedometerUIOptions.setTextColor(minorSpeedAlertTextColor, for: .minor,
lightingMode: .normal)
mutableSpeedometerUIOptions.setTextColor(majorSpeedAlertTextColor, for: .major,
lightingMode: .normal)
mutableSpeedometerUIOptions.setBackgroundColor(minorSpeedAlertNightModeBackgroundColor,
for: .minor, lightingMode: .lowLight)
mutableSpeedometerUIOptions.setBackgroundColor(majorSpeedAlertDayModeBackgroundColor,
for: .major, lightingMode: .normal)

mapView.settings.speedometerUIOptions = mutableSpeedometerUIOptions

Objective-C

GMSNavigationMutableSpeedometerUIOptions *mutableSpeedometerUIOptions =
[[GMSNavigationMutableSpeedometerUIOptions alloc] init];
[mutableSpeedometerUIOptions setTextColor: minorSpeedAlertTextColor
forSpeedAlertSeverity: GMSNavigationSpeedAlertSeverityMinor lightingMode:
GMSNavigationLightingModeNormal]; [mutableSpeedometerUIOptions setTextColor:
majorSpeedAlertTextColor forSpeedAlertSeverity:
GMSNavigationSpeedAlertSeverityMajor lightingMode:
GMSNavigationLightingModeNormal]; [mutableSpeedometerUIOptions
setBackgroundColor: minorSpeedAlertNightModeBackgroundColor
forSpeedAlertSeverity: GMSNavigationSpeedAlertSeverityMinor lightingMode:
GMSNavigationLightingModeLowLight]; [mutableSpeedometerUIOptions
setBackgroundColor: majorSpeedAlertDayModeBackgroundColor forSpeedAlertSeverity:
GMSNavigationSpeedAlertSeverityMajor
lightingMode:GMSNavigationLightingModeNormal];

mapView.settings.speedometerUIOptions = mutableSpeedometerUIOptions;

接收司机发送的速度信息

如果您的应用需要分享有关驾驶员速度的信息，您还可以使用 Navigation SDK 来提供驾驶员的速度信息。这对于网约车应用非常有用，因为运营商可能希望监控司机的超速行为，以提高安全性。

例如，以下示例会在速度超过速度限制的指定百分比时分享速度信息：

Swift

// Listener method for sharing speed information when the speed exceeds the
speed limit by a specified percentage. #pragma mark GMSNavigatorListener func
navigator(_ navigator : GMSNavigator, didUpdateSpeedingPercentage
percentageAboveLimit : Float) { ... }

Objective-C

// Listener method listening to speeding feed. #pragma mark
GMSNavigatorListener - (void)navigator:(GMSNavigator *)navigator
didUpdateSpeedingPercentage:(float)percentageAboveLimit { ... }