Block Events

dev.architectury.event.events.common.BlockEvent

Events about blocks being broken, placed, landed on by a falling block, or moved by a piston.

Events

Event	Listener method	Returns
BREAK	breakBlock(Level, BlockPos, BlockState, ServerPlayer)	EventResult - interrupt to cancel the break.
PLACE	placeBlock(Level, BlockPos, BlockState, Entity placer)	EventResult - interrupt to cancel the placement.
FALLING_LAND	onLand(Level, BlockPos, BlockState fallState, BlockState landOn, FallingBlockEntity)	void (notification).
PISTON_PRE	piston(Level, BlockPos, Direction, boolean extending)	EventResult - interrupt to stop the piston moving.
PISTON_POST	piston(Level, BlockPos, Direction, boolean extending)	void (notification).

Added in 21.1

PISTON_PRE and PISTON_POST were added in Architectury API 21.1.

For PLACE, the placer may be null (for example, when a dispenser places the block).

Piston events

PISTON_PRE fires after vanilla has decided a piston should move but before any blocks are moved; PISTON_POST fires once the move has completed. PISTON_POST does not fire when the move was refused, either by vanilla or by a listener interrupting PISTON_PRE.

Both events give you the position of the piston base, the direction it faces, and whether it is extending (true) or retracting (false). Both fire on the logical client and the logical server, so check level.isClientSide() if you only want one side.

These mirror NeoForge's PistonEvent.Pre and PistonEvent.Post. Fabric has no equivalent, so Architectury supplies them with a mixin there.

Examples

Protect bedrock from being broken:

BlockEvent.BREAK.register((level, pos, state, player) -> {
    if (state.is(Blocks.BEDROCK)) {
        return EventResult.interruptFalse(); // deny the break
    }
    return EventResult.pass();
});

React to a falling block landing:

BlockEvent.FALLING_LAND.register((level, pos, fallState, landOn, entity) -> {
    // e.g. spawn particles where the block landed
});

Stop pistons from working inside a protected region:

BlockEvent.PISTON_PRE.register((level, pos, direction, extending) -> {
    if (isProtected(level, pos)) {
        return EventResult.interruptFalse(); // the piston does not move
    }
    return EventResult.pass();
});

BlockEvent.PISTON_POST.register((level, pos, direction, extending) -> {
    // the piston has finished extending or retracting
});