啟用導航功能並將交通方式設為開車時，iOS 版 Navigation SDK 會在地圖左下角顯示速限控制項，顯示目前的速限。如果駕駛人超過速限，控制項會展開，在速限顯示旁邊顯示計速器，並在速度達到特定門檻時觸發警報。
根據預設，如果駕駛人超過速限 5 英里/時 (或 10 公里/時)，Navigation SDK 就會觸發輕微的速度警示，並將速度計文字的顏色變更為紅色。如果駕駛人超速 10 英里/時 (或 20 公里/時)，系統會觸發重大超速警示，並將速度計背景顏色變更為紅色。
您可以自訂觸發快訊的門檻，以及速度計顯示的文字和背景顏色。您也可以使用 Navigation SDK 提供駕駛人的車速資訊。舉例來說，您可以向共乘服務業者提供車速資訊，協助他們鼓勵駕駛人遵守速限，進而提升安全性。
自訂速度快訊的門檻
你可以自訂輕微和重大超速警示的速限百分比門檻。您也可以指定地圖顯示快訊前，超出門檻的時間長度。
下列程式碼範例會將輕微超速警示的速限門檻設為超過速限 5%，嚴重超速警示的速限門檻則設為超過速限 10%。這項設定指定地圖在警示閾值超過五秒後顯示警示。
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.
自訂車速表顯示車速快訊的方式
你可以為每個警報等級自訂速度表顯示的顏色。
下表顯示 GMSNavigationSpeedometerUIOptions 類別中速限快訊的預設顏色：
| 元素 | 顏色 |
|---|---|
| MinorSpeedAlertBackgroundColorDayMode | 0xffffff(白色) |
| MinorSpeedAlertBackgroundColorNightMode | 0x000000 |
| MinorSpeedAlertTextColorDayMode | 0xd93025 |
| MinorSpeedAlertTextColorNightMode | 0xd93025 |
| MajorSpeedAlertBackgroundColorDayMode | 0xd93025 |
| MajorSpeedAlertBackgroundColorNightMode | 0xd93025 |
| MajorSpeedAlertTextColorDayMode | 0xffffff(白色) |
| MajorSpeedAlertTextColorNightMode | 0xffffff(白色) |
您可以為次要和主要速度快訊指定速度表的文字和背景顏色：
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;
接收駕駛人的速度資訊
如果應用程式需要分享駕駛人的車速資訊，您也可以使用 Navigation SDK 提供駕駛人的車速資訊。這項功能適用於共乘應用程式，因為營運人員可能想監控駕駛人是否超速，以提升安全性。
舉例來說，以下範例會在車速超過速限的指定百分比時分享車速資訊：
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 { ... }