mobileSetLocationHistoryLimit

Type

command

Summary

Set the number of location changes to be retained

Syntax

mobileSetLocationHistoryLimit <historyLimit>

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 mobileGetLocationHistory function returns a numerically keyed array of all accumulated samples since the last time it was called with lower indices being older samples. Calling the function clears the internal history.

Each element in the array is the same format as the detailed location array as returned from the mobileSensorReading function.

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

Parameters

Name	Type	Description
historyLimit	integer	The number of entries to retain from system locationChanged events. 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 to the maximum number of samples it ever wants to record, or 0 to record the entire history (between calls to mobileGetLocationHistory).

Examples

-- retain all between calls to mobileGetLocationHistory()
mobileSetLocationHistoryLimit 0

-- retain the most recent 10 locations
mobileSetLocationHistoryLimit 10

Related

message: locationChanged, trackingError

command: mobileStopTrackingSensor, mobileStartTrackingSensor

function: mobileGetLocationHistory, mobileGetLocationHistoryLimit, mobileSensorAvailable, mobileSensorReading, mobileLocationAuthorizationStatus

glossary: function

Compatibility and Support

Introduced

LiveCode 8.1

OS

ios

android

Platforms

mobile