mobileGetLocationHistory

Type

function

Summary

Get the mobile location samples since the last call to mobileGetLocationHistory

Syntax

mobileGetLocationHistory()

Description

System locationChanged events may occur more frequently than the locationChanged message is sent because messages that were unable to be sent as a result of other scripts executing are filtered when a new system locationChanged event occurs.

Whenever a system locationChanged event occurs, the location reading is pushed onto the front of a list. The list is capped at the length set by mobileSetLocationHistoryLimit, dropping any old samples over this length.

The best way to use the history is to fetch the list in locationChanged and process each sample in turn, rather than the sample provided with the locationChanged event (which will always be the last sample in the history). e.g.

    on locationChanged
        local tHistory
        put mobileGetLocationHistory() into tHistory
        repeat for each element tSample in tHistory
            processLocationChanged tSample
        end repeat
    end locationChanged

Examples

local tHistory
put mobileGetLocationHistory() into tHistory

Value

Name	Type	Description
return	array	A numerically keyed, nested array of all accumulated samples since the last time it was called with lower indices being older samples. Each index of the array has the following keys: "horizontal accuracy": the maximum error in meters of the position indicated by longitude and latitude "latitude": the latitude of the current location, measured in degrees relative to the equator. Positive values indicate positions in the Northern Hemisphere, negative values in the Southern. "longitude": the longitude of the current location, measured in degrees relative to the zero meridian. Positive values extend east of the meridian, negative values extend west. "altitude": the distance in meters of the height of the device relative to sea level. Positive values extend upward of sea level, negative values downward. "timestamp": the time at which the measurement was taken, in seconds since 1970. Calling the function clears the internal history. The default history limit is 1, meaning that only one sample is ever kept at a time. If an application wants historical access to all samples, then it should set the location history limit using the mobileSetLocationHistoryLimit command to the maximum number of samples it ever wants to record, or 0 to record the entire history (between calls to mobileGetLocationHistory).

Related

message: locationChanged, trackingError

command: mobileSetLocationHistoryLimit, mobileStopTrackingSensor, mobileStartTrackingSensor

function: mobileGetLocationHistoryLimit, mobileSensorAvailable, mobileSensorReading, mobileLocationAuthorizationStatus

Compatibility and Support

Introduced

LiveCode 8.1

OS

ios

android

Platforms

mobile