On the client, screen handlers are coupled with a {@link COMMENT net.minecraft.client.gui.screen.ingame.HandledScreen}. Handled screens have a COMMENT reference to a client-sided screen handler that is exposed through the COMMENT {@link net.minecraft.client.gui.screen.ingame.ScreenHandlerProvider} interface. COMMENT COMMENT
Screen handlers hold slots, properties, property delegates, and screen handler COMMENT contexts. This allows easy synchronization of states between the client and the COMMENT server, and prevents running code on the wrong side. COMMENT COMMENT
{@link Slot} holds one item stack. The slots are usually controlled by the server, COMMENT and the changes to slots on the server are automatically synchronized to the client. COMMENT Slots can be backed by an inventory, allowing the changes to be reflected to the COMMENT persistent storage (like block entities) on the server. Clients manipulate the COMMENT slots by issuing a "slot click" packet. "Clicking" a slot includes actions like COMMENT picking up crafting result, shift-clicking stacks, swapping stacks between the COMMENT inventory and the hotbar, or dropping stacks. COMMENT COMMENT
Screen handlers also contain a list of {@linkplain Property properties} COMMENT that are used for syncing integers (e.g. progress bars) from the server to the client. COMMENT Properties can also be used to sync an integer from the client to the server, although COMMENT it has to be manually performed. If a property relies on other objects, like COMMENT a value from a block entity instance, then the property can delegate its operations COMMENT using {@link PropertyDelegate}. The delegate is passed when creating the screen handler. COMMENT On the server, access to the property's value is delegated to the delegate (which in COMMENT turn delegates to another object like a block entity instance). COMMENT On the client, access to the property's value still uses the synced value. COMMENT COMMENT
{@link ScreenHandlerContext} allows running code on the server side only. Screen COMMENT handlers are designed to be used on both sides; any action modifying the world has COMMENT to be wrapped in a call to the context. Like with the property delegate, a context COMMENT with the world is passed to the screen handler on creation on the server. On the COMMENT server, the context executes the function with the world and the position. On the COMMENT client, the context does nothing. COMMENT COMMENT
To create a new screen handler, subclass {@link ScreenHandler}, create and register COMMENT a new {@linkplain ScreenHandlerType screen handler type}, and associate it with COMMENT a handled screen. COMMENT COMMENT
A subclass should have two constructors. One is for the server, and should take COMMENT the {@code syncId} and inventories, property delegates, or contexts that are used. COMMENT The {@link #syncId} is shared between the two sides. It is used to verify that a player COMMENT has a specific screen (handler) open so that they can move items, for example. COMMENT The inventories are used to back a slot so that any changes to a slot is reflected COMMENT on the backing inventory, and vice versa. Property delegates and contexts bridge COMMENT between the screen handler and other parts of the world; see above for more description. COMMENT COMMENT
The constructor should {@linkplain #addSlot add slots}, {@link #addProperties COMMENT add properties from delegates}, and store the property delegates and screen handler COMMENT context in the instance fields. COMMENT COMMENT
The other constructor is for the client. There, the only parameters allowed are the COMMENT {@code syncId} and the player inventory. This is because all other things are COMMENT unavailable at creation time and synced later. This constructor should call the COMMENT other constructor with {@linkplain net.minecraft.inventory.SimpleInventory COMMENT a new simple inventory of sufficient size}, {@linkplain ArrayPropertyDelegate COMMENT a new array property delegate}, and {@linkplain ScreenHandlerContext#EMPTY COMMENT an empty screen handler context}. Synced data then fills the inventory and property COMMENT delegate. COMMENT COMMENT
The screen handler then has to be registered in a registry. Create a new instance of COMMENT {@link ScreenHandlerType} with the screen handler type factory (which can be a reference COMMENT to the client-side constructor; i.e. {@code MyScreenHandler::MyScreenHandler}) COMMENT and register it to {@link net.minecraft.registry.Registries#SCREEN_HANDLER}. COMMENT COMMENT
Most of the screen handlers are associated with a block and opened by using the block. COMMENT Screen handlers are opened on the server and synced to the client. To open a COMMENT screen handler, use {@link PlayerEntity#openHandledScreen}. This takes a COMMENT {@link NamedScreenHandlerFactory}, which creates a screen handler. In vanilla, COMMENT block entity instances implement the interface, allowing them to be passed. COMMENT {@link SimpleNamedScreenHandlerFactory} is a screen handler factory implementation COMMENT for use cases that do not involve a block entity. COMMENT COMMENT
The factory should create a new instance of a screen handler with the server-side COMMENT constructor (one that takes inventories, etc). If the screen handler requires COMMENT a property delegate or a context, create an instance and pass it here. COMMENT COMMENT
As long as the screen handler only uses the slots and properties, there should not COMMENT be any need for external synchronization. COMMENT COMMENT
Screen handler interaction mainly involves "slot clicks" and "button clicks". COMMENT A {@linkplain #onSlotClick slot click} is, as mentioned before, an action manipulating COMMENT the slots' held item stacks. Slot clicks are implemented in this class and COMMENT {@link #quickMove}. To manipulate the stacks, get the slot via {@link #getSlot} COMMENT and call methods of it. Screen handlers also provide methods for common operations, COMMENT such as {@link #insertItem} that inserts a stack to the screen handler's available slots. COMMENT COMMENT
The "cursor stack" is an item stack held by the cursor. When moving item stacks COMMENT between slots, the cursor stack can hold the stack temporarily. The cursor stack COMMENT is not held by any slots. When the screen handler is closed, the stack will be COMMENT inserted to the player inventory or dropped as an item entity. COMMENT COMMENT
Some screen handlers also handle {@linkplain #onButtonClick button clicks}. COMMENT This is used to execute an action on the server as a response to clients sending a COMMENT button click packet. In most cases, this is triggered by a button in the screen COMMENT rendered by the client, hence the name. Inside screen handlers, buttons are identified COMMENT with an integer. COMMENT COMMENT
Subclasses must implement two methods: {@link #canUse(PlayerEntity)} and {@link COMMENT #quickMove}. See the documentation of each method for more details. COMMENT COMMENT
Since a screen handler handles the client's screen, the screen must be closed at the COMMENT same time. To close the screen handler and the screen, call {@link COMMENT PlayerEntity#closeHandledScreen} on the server. COMMENT COMMENT
Screen handlers should override {@link #onClosed}. In there, it should {@linkplain
COMMENT #dropInventory drop contents} of all slots not backed by an inventory and call
COMMENT {@link Inventory#onClose} on the backing inventory. See the documentation of
COMMENT the method for more details.
COMMENT
COMMENT @see ScreenHandlerType
COMMENT @see ScreenHandlerFactory
COMMENT @see Slot
COMMENT @see Inventory
COMMENT @see net.minecraft.client.gui.screen.ingame.HandledScreen
FIELD field_17285 properties Ljava/util/List;
FIELD field_17493 type Lnet/minecraft/class_3917;
FIELD field_29205 cursorStack Lnet/minecraft/class_1799;
FIELD field_29206 previousTrackedStacks Lnet/minecraft/class_2371;
FIELD field_29207 previousCursorStack Lnet/minecraft/class_1799;
FIELD field_29208 syncHandler Lnet/minecraft/class_5916;
FIELD field_29209 disableSync Z
FIELD field_29559 trackedPropertyValues Lit/unimi/dsi/fastutil/ints/IntList;
FIELD field_30730 EMPTY_SPACE_SLOT_INDEX I
COMMENT A special slot index value ({@value}) indicating that the player has clicked outside the main panel
COMMENT of a screen. Used for dropping the cursor stack.
FIELD field_34024 revision I
FIELD field_36534 LOGGER Lorg/slf4j/Logger;
FIELD field_7757 quickCraftSlots Ljava/util/Set;
FIELD field_7759 quickCraftStage I
FIELD field_7761 slots Lnet/minecraft/class_2371;
FIELD field_7762 quickCraftButton I
FIELD field_7763 syncId I
FIELD field_7764 trackedStacks Lnet/minecraft/class_2371;
COMMENT A list of item stacks that is used for tracking changes in {@link #sendContentUpdates()}.
FIELD field_7765 listeners Ljava/util/List;
METHOD A screen handler must have associated screen handler type to open it.
COMMENT
COMMENT @throws UnsupportedOperationException if the type is not passed in the constructor
METHOD method_17359 checkSize (Lnet/minecraft/class_1263;I)V
COMMENT Checks that the size of the provided inventory is at least as large as the {@code expectedSize}.
COMMENT
COMMENT @throws IllegalArgumentException if the inventory size is smaller than {@code expectedSize}
ARG 0 inventory
ARG 1 expectedSize
METHOD method_17360 addProperties (Lnet/minecraft/class_3913;)V
COMMENT Adds properties of {@code propertyDelegate} to this screen handler.
COMMENT This must be called inside the subclass's constructor.
COMMENT
COMMENT @see #addProperty
ARG 1 propertyDelegate
METHOD method_17361 checkDataCount (Lnet/minecraft/class_3913;I)V
COMMENT Checks that the size of the {@code data} is at least as large as the {@code expectedCount}.
COMMENT
COMMENT @throws IllegalArgumentException if the {@code data} has a smaller size than {@code expectedCount}
ARG 0 data
ARG 1 expectedCount
METHOD method_17362 addProperty (Lnet/minecraft/class_3915;)Lnet/minecraft/class_3915;
COMMENT Adds {@code property} to this screen handler. This must be called inside the
COMMENT subclass's constructor.
COMMENT
COMMENT If the property relies on external objects (such as a block entity instance),
COMMENT it should instead use property delegates and {@link #addProperties}.
COMMENT
COMMENT @return the added property
COMMENT
COMMENT @see #addProperties
ARG 1 property
METHOD method_17695 canUse (Lnet/minecraft/class_3914;Lnet/minecraft/class_1657;Lnet/minecraft/class_2248;)Z
COMMENT {@return whether the screen handler can be used}
COMMENT
COMMENT @apiNote This should be called inside {@link #canUse(PlayerEntity)}.
COMMENT
COMMENT @implNote On the server, this checks that the block at the position is
COMMENT {@code block} and the player is within 8 blocks from the block's center.
COMMENT
COMMENT @see #canUse(PlayerEntity)
ARG 0 context
ARG 1 player
ARG 2 block
METHOD method_17696 (Lnet/minecraft/class_2248;Lnet/minecraft/class_1657;Lnet/minecraft/class_1937;Lnet/minecraft/class_2338;)Ljava/lang/Boolean;
ARG 2 world
ARG 3 pos
METHOD method_30010 internalOnSlotClick (IILnet/minecraft/class_1713;Lnet/minecraft/class_1657;)V
COMMENT The actual logic that handles a slot click. Called by {@link #onSlotClick
COMMENT (int, int, SlotActionType, PlayerEntity)} in a try-catch block that wraps
COMMENT exceptions from this method into a crash report.
ARG 1 slotIndex
ARG 2 button
ARG 3 actionType
ARG 4 player
METHOD method_34245 setPreviousTrackedSlot (ILnet/minecraft/class_1799;)V
ARG 1 slot
ARG 2 stack
METHOD method_34246 updateTrackedSlot (ILnet/minecraft/class_1799;Ljava/util/function/Supplier;)V
ARG 1 slot
ARG 2 stack
ARG 3 copySupplier
METHOD method_34247 copySharedSlots (Lnet/minecraft/class_1703;)V
ARG 1 handler
METHOD method_34248 updateSyncHandler (Lnet/minecraft/class_5916;)V
ARG 1 handler
METHOD method_34249 (Lnet/minecraft/class_1735;Lnet/minecraft/class_1657;Lnet/minecraft/class_1799;)V
ARG 3 stack
METHOD method_34250 setPreviousCursorStack (Lnet/minecraft/class_1799;)V
ARG 1 stack
METHOD method_34251 (Lnet/minecraft/class_1799;Lnet/minecraft/class_1735;Lnet/minecraft/class_1657;Lnet/minecraft/class_1799;)V
ARG 3 stack
METHOD method_34252 syncState ()V
METHOD method_34253 checkSlotUpdates (ILnet/minecraft/class_1799;Ljava/util/function/Supplier;)V
ARG 1 slot
ARG 2 stack
ARG 3 copySupplier
METHOD method_34254 setCursorStack (Lnet/minecraft/class_1799;)V
ARG 1 stack
METHOD method_34255 getCursorStack ()Lnet/minecraft/class_1799;
METHOD method_34256 disableSyncing ()V
METHOD method_34257 enableSyncing ()V
METHOD method_34258 checkCursorStackUpdates ()V
METHOD method_34259 getCursorStackReference ()Lnet/minecraft/class_5630;
COMMENT {@return a reference to the cursor's stack}
METHOD method_34715 checkPropertyUpdates (II)V
ARG 1 id
ARG 2 value
METHOD method_37418 getSlotIndex (Lnet/minecraft/class_1263;I)Ljava/util/OptionalInt;
ARG 1 inventory
ARG 2 index
METHOD method_37419 notifyPropertyUpdate (II)V
ARG 1 index
ARG 2 value
METHOD method_37420 updateToClient ()V
METHOD method_37421 getRevision ()I
METHOD method_37422 nextRevision ()I
METHOD method_37449 setPreviousTrackedSlotMutable (ILnet/minecraft/class_1799;)V
ARG 1 slot
ARG 2 stack
METHOD method_40442 isValid (I)Z
COMMENT {@return whether the given slot index is valid}
COMMENT
COMMENT This returns {@code true} for all added slots, {@value #EMPTY_SPACE_SLOT_INDEX},
COMMENT and {@code -1}.
ARG 1 slot
METHOD method_45409 handleSlotClick (Lnet/minecraft/class_1657;Lnet/minecraft/class_5536;Lnet/minecraft/class_1735;Lnet/minecraft/class_1799;Lnet/minecraft/class_1799;)Z
ARG 1 player
ARG 2 clickType
ARG 3 slot
ARG 4 stack
ARG 5 cursorStack
METHOD method_7591 packQuickCraftData (II)I
ARG 0 quickCraftStage
ARG 1 buttonId
METHOD method_7592 canInsertItemIntoSlot (Lnet/minecraft/class_1735;Lnet/minecraft/class_1799;Z)Z
ARG 0 slot
ARG 1 stack
ARG 2 allowOverflow
METHOD method_7593 onSlotClick (IILnet/minecraft/class_1713;Lnet/minecraft/class_1657;)V
COMMENT Performs a slot click. This can behave in many different ways depending mainly on the action type.
ARG 1 slotIndex
ARG 2 button
ARG 3 actionType
COMMENT the type of slot click, check the docs for each {@link SlotActionType} value for details
ARG 4 player
METHOD method_7594 unpackQuickCraftStage (I)I
ARG 0 quickCraftData
METHOD method_7595 onClosed (Lnet/minecraft/class_1657;)V
COMMENT Called when this screen handler is closed.
COMMENT
COMMENT To close a screen handler, call {@link PlayerEntity#closeHandledScreen}
COMMENT on the server instead of this method.
COMMENT
COMMENT This drops the cursor stack by default. Subclasses that have slots not backed
COMMENT by a persistent inventory should call {@link #dropInventory} to drop the stacks.
ARG 1 player
METHOD method_7596 addListener (Lnet/minecraft/class_1712;)V
COMMENT Adds {@code listener} to the screen handler.
COMMENT
COMMENT Listeners are often used to listen to slot or property changes on the
COMMENT client's screen.
ARG 1 listener
METHOD method_7597 canUse (Lnet/minecraft/class_1657;)Z
COMMENT {@return whether the screen handler can be used}
COMMENT
COMMENT Subclasses should call #canUse(ScreenHandlerContext, PlayerEntity, Block)}
COMMENT or implement the check itself. The implementation should check that the
COMMENT player is near the screen handler's source position (e.g. block position) and
COMMENT that the source (e.g. block) is not destroyed.
ARG 1 player
METHOD method_7600 shouldQuickCraftContinue (ILnet/minecraft/class_1657;)Z
ARG 0 stage
ARG 1 player
METHOD method_7601 quickMove (Lnet/minecraft/class_1657;I)Lnet/minecraft/class_1799;
COMMENT Quick-moves the stack at {@code slot} to other
COMMENT slots of the screen handler that belong to a different inventory or
COMMENT another section of the same inventory. For example, items can be quick-moved
COMMENT between a chest's slots and the player inventory or between the main player inventory
COMMENT and the hotbar.
COMMENT
COMMENT Subclasses should call {@link #insertItem}, and if the insertion was successful,
COMMENT clear the slot (if the stack is exhausted) or mark it as dirty. See the vanilla
COMMENT subclasses for basic implementation.
COMMENT
COMMENT Quick-moving is also known as "shift-clicking" since it's usually triggered
COMMENT using Shift+left click.
COMMENT
COMMENT @return {@link ItemStack#EMPTY} when no stack can be transferred, otherwise
COMMENT the original stack
COMMENT
COMMENT @see #insertItem
ARG 1 player
ARG 2 slot
COMMENT the index of the slot to quick-move from
METHOD method_7602 getStacks ()Lnet/minecraft/class_2371;
COMMENT {@return a list of all stacks of the screen handler's slot}
COMMENT
COMMENT This should not be used in most cases, and modifying the returned list
COMMENT has no effect to the screen handler.
METHOD method_7603 removeListener (Lnet/minecraft/class_1712;)V
COMMENT Removes {@code listener} from this screen handler.
ARG 1 listener
METHOD method_7604 onButtonClick (Lnet/minecraft/class_1657;I)Z
COMMENT Called when {@code player} clicks a button with {@code id}.
COMMENT
COMMENT "Button click" is an abstract concept; it does not have to be triggered by a
COMMENT button. Examples of button clicks include selecting a recipe for a stonecutter,
COMMENT turning a page of a lectern's book, or selecting an enchantment on an enchanting table.
COMMENT Buttons are identified by an integer.
COMMENT
COMMENT @implNote This is normally only called by the server; however, screens that use buttons
COMMENT can call this on the client.
COMMENT
COMMENT @return whether the button click is handled successfully
ARG 1 player
ARG 2 id
METHOD method_7605 endQuickCraft ()V
METHOD method_7606 setProperty (II)V
COMMENT Sets the property with ID {@code id} to {@code value}.
COMMENT
COMMENT Subclasses can call {@link #sendContentUpdates} to manually sync the change
COMMENT to the client.
ARG 1 id
ARG 2 value
METHOD method_7607 dropInventory (Lnet/minecraft/class_1657;Lnet/minecraft/class_1263;)V
ARG 1 player
ARG 2 inventory
METHOD method_7608 calculateComparatorOutput (Lnet/minecraft/class_2586;)I
ARG 0 entity
METHOD method_7609 onContentChanged (Lnet/minecraft/class_1263;)V
COMMENT Called when a slot's content has changed.
COMMENT
COMMENT This is not called by default; subclasses that override this method
COMMENT should also use a custom {@link Inventory} whose {@link Inventory#markDirty markDirty} method is
COMMENT overridden to call this method as a backing inventory of the slot.
COMMENT
COMMENT This can be used to update the output slot when input changes.
ARG 1 inventory
METHOD method_7610 updateSlotStacks (ILjava/util/List;Lnet/minecraft/class_1799;)V
ARG 1 revision
ARG 2 stacks
ARG 3 cursorStack
METHOD method_7611 getSlot (I)Lnet/minecraft/class_1735;
COMMENT {@return the slot with index {@code index}}
ARG 1 index
METHOD method_7613 canInsertIntoSlot (Lnet/minecraft/class_1799;Lnet/minecraft/class_1735;)Z
COMMENT {@return whether {@code stack} can be inserted to {@code slot}}
COMMENT
COMMENT Subclasses should override this to return {@code false} if the slot is
COMMENT used for output.
ARG 1 stack
ARG 2 slot
METHOD method_7615 canInsertIntoSlot (Lnet/minecraft/class_1735;)Z
ARG 1 slot
METHOD method_7616 insertItem (Lnet/minecraft/class_1799;IIZ)Z
COMMENT Tries to consume {@code stack} by inserting to slots from {@code startIndex}
COMMENT to {@code endIndex - 1} (both inclusive) until the entire stack is used.
COMMENT
COMMENT If {@code fromLast} is {@code true}, this attempts the insertion in reverse
COMMENT order; i.e. {@code endIndex - 1} to {@code startIndex} (both inclusive).
COMMENT
COMMENT @return whether {@code stack} was decremented
ARG 1 stack
ARG 2 startIndex
ARG 3 endIndex
ARG 4 fromLast
METHOD method_7617 calculateStackSize (Ljava/util/Set;ILnet/minecraft/class_1799;)I
ARG 0 slots
ARG 1 mode
ARG 2 stack
METHOD method_7618 calculateComparatorOutput (Lnet/minecraft/class_1263;)I
ARG 0 inventory
METHOD method_7619 setStackInSlot (IILnet/minecraft/class_1799;)V
ARG 1 slot
ARG 2 revision
ARG 3 stack
METHOD method_7620 unpackQuickCraftButton (I)I
ARG 0 quickCraftData
METHOD method_7621 addSlot (Lnet/minecraft/class_1735;)Lnet/minecraft/class_1735;
COMMENT Adds {@code slot} to this screen handler. This must be called inside
COMMENT the subclass's constructor.
COMMENT
COMMENT @return the added slot
ARG 1 slot
METHOD method_7623 sendContentUpdates ()V
COMMENT Sends updates to listeners if any properties or slot stacks have changed.