lockScreen

Type

property

Summary

Specifies whether changes to a stack appear on the screen.

Syntax

set the lockScreen to {true | false}

Description

Use the lockScreen property to control when changes to the appearance of objects appear to the user, or to speed up actions that change several objects.

If the lockScreen property is set to true, statements that affect the appearance of the stack windows--such as opening or closing a stack, going to another card, or changing properties of an object --are not shown on the screen until the lockScreen is set back to false.

If the lockScreen is false, all changes are displayed immediately.

Setting the lockScreen to true also speeds up handlers that affect the screen appearance. Since LiveCode does not need to take time redrawing its windows when the lockScreen is true, a handler that visits several cards in a row or changes several objects runs faster if the lockScreen property is set to true while the changes are made.

The lockScreen property is automatically set to false when a palette, modeless, or modal stack is opened, even if a handler is still running.

Important

Open stacks cannot be brought to the front (using the go or topLevel command) while the lockScreen is true.

LiveCode keeps count of how many times the screen has been locked. You must balance each unlock with a lock; if you lock the screen twice and then unlock it once, the screen remains locked. For example, the following pair of handlers draws everything while the display is still locked:

    on mouseUp
        lock screen    -- first lock
        drawStuff      -- gets locked again and unlocked in drawStuff
        show image \"Sprite\"
        unlock screen  -- now unlocked - 2 locks balanced by 2 unlocks
    end mouseUp

    on drawStuff
        lock screen    -- screen now locked twice
        show field \"Notify\"
        unlock screen  -- not unlocked yet - locked twice, unlocked once
    end drawStuff

note

When using script debug mode, the screen cannot be locked and the setting of the lockScreen property has no effect.

Examples

set the lockScreen to (not the lockScreen)

Related

function: stacks

glossary: object, property, stack window, handler, execute, statement, redraw, script debug mode, command

keyword: card

object: stack, card

property: properties, lockCursor

command: unlock screen, topLevel, palette, modal, reset, go, show cards, modeless

Compatibility and Support

Introduced

LiveCode 1.0

OS

mac

windows

linux

ios

android

Platforms

desktop

server

mobile