Copyright | Will Thompson and Iñaki García Etxebarria |
---|---|
License | LGPL-2.1 |
Maintainer | Iñaki García Etxebarria |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
GtkDropTarget
is an event controller to receive Drag-and-Drop operations.
The most basic way to use a GtkDropTarget
to receive drops on a
widget is to create it via dropTargetNew
, passing in the
GType
of the data you want to receive and connect to the
DropTarget::drop signal to receive the data:
c code
static gboolean on_drop (GtkDropTarget *target, const GValue *value, double x, double y, gpointer data) { MyWidget *self = data; // Call the appropriate setter depending on the type of data // that we received if (G_VALUE_HOLDS (value, G_TYPE_FILE)) my_widget_set_file (self, g_value_get_object (value)); else if (G_VALUE_HOLDS (value, GDK_TYPE_PIXBUF)) my_widget_set_pixbuf (self, g_value_get_object (value)); else return FALSE; return TRUE; } static void my_widget_init (MyWidget *self) { GtkDropTarget *target = gtk_drop_target_new (G_TYPE_INVALID, GDK_ACTION_COPY); // This widget accepts two types of drop types: GFile objects // and GdkPixbuf objects gtk_drop_target_set_gtypes (target, (GTypes [2]) { G_TYPE_FILE, GDK_TYPE_PIXBUF, }, 2); g_signal_connect (target, "drop", G_CALLBACK (on_drop), self); gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (target)); }
GtkDropTarget
supports more options, such as:
- rejecting potential drops via the DropTarget::accept signal
and the
dropTargetReject
function to let other drop targets handle the drop - tracking an ongoing drag operation before the drop via the DropTarget::enter, DropTarget::motion and DropTarget::leave signals
- configuring how to receive data by setting the DropTarget:preload property and listening for its availability via the DropTarget:value property
However, GtkDropTarget
is ultimately modeled in a synchronous way
and only supports data transferred via GType
. If you want full control
over an ongoing drop, the DropTargetAsync
object gives you
this ability.
While a pointer is dragged over the drop target's widget and the drop
has not been rejected, that widget will receive the
StateFlagsDropActive
state, which can be used to style the widget.
If you are not interested in receiving the drop, but just want to update
UI state during a Drag-and-Drop operation (e.g. switching tabs), you can
use DropControllerMotion
.
Synopsis
- newtype DropTarget = DropTarget (ManagedPtr DropTarget)
- class (GObject o, IsDescendantOf DropTarget o) => IsDropTarget o
- toDropTarget :: (MonadIO m, IsDropTarget o) => o -> m DropTarget
- dropTargetGetActions :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m [DragAction]
- dropTargetGetCurrentDrop :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m (Maybe Drop)
- dropTargetGetDrop :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m (Maybe Drop)
- dropTargetGetFormats :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m (Maybe ContentFormats)
- dropTargetGetGtypes :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m (Maybe [GType])
- dropTargetGetPreload :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m Bool
- dropTargetGetValue :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m (Maybe GValue)
- dropTargetNew :: (HasCallStack, MonadIO m) => GType -> [DragAction] -> m DropTarget
- dropTargetReject :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> m ()
- dropTargetSetActions :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> [DragAction] -> m ()
- dropTargetSetGtypes :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> Maybe [GType] -> m ()
- dropTargetSetPreload :: (HasCallStack, MonadIO m, IsDropTarget a) => a -> Bool -> m ()
- constructDropTargetActions :: (IsDropTarget o, MonadIO m) => [DragAction] -> m (GValueConstruct o)
- getDropTargetActions :: (MonadIO m, IsDropTarget o) => o -> m [DragAction]
- setDropTargetActions :: (MonadIO m, IsDropTarget o) => o -> [DragAction] -> m ()
- getDropTargetCurrentDrop :: (MonadIO m, IsDropTarget o) => o -> m (Maybe Drop)
- constructDropTargetFormats :: (IsDropTarget o, MonadIO m) => ContentFormats -> m (GValueConstruct o)
- getDropTargetFormats :: (MonadIO m, IsDropTarget o) => o -> m (Maybe ContentFormats)
- constructDropTargetPreload :: (IsDropTarget o, MonadIO m) => Bool -> m (GValueConstruct o)
- getDropTargetPreload :: (MonadIO m, IsDropTarget o) => o -> m Bool
- setDropTargetPreload :: (MonadIO m, IsDropTarget o) => o -> Bool -> m ()
- getDropTargetValue :: (MonadIO m, IsDropTarget o) => o -> m (Maybe GValue)
- type DropTargetAcceptCallback = Drop -> IO Bool
- afterDropTargetAccept :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetAcceptCallback) -> m SignalHandlerId
- onDropTargetAccept :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetAcceptCallback) -> m SignalHandlerId
- type DropTargetDropCallback = GValue -> Double -> Double -> IO Bool
- afterDropTargetDrop :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetDropCallback) -> m SignalHandlerId
- onDropTargetDrop :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetDropCallback) -> m SignalHandlerId
- type DropTargetEnterCallback = Double -> Double -> IO [DragAction]
- afterDropTargetEnter :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetEnterCallback) -> m SignalHandlerId
- onDropTargetEnter :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetEnterCallback) -> m SignalHandlerId
- type DropTargetLeaveCallback = IO ()
- afterDropTargetLeave :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetLeaveCallback) -> m SignalHandlerId
- onDropTargetLeave :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetLeaveCallback) -> m SignalHandlerId
- type DropTargetMotionCallback = Double -> Double -> IO [DragAction]
- afterDropTargetMotion :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetMotionCallback) -> m SignalHandlerId
- onDropTargetMotion :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetMotionCallback) -> m SignalHandlerId
Exported types
newtype DropTarget Source #
Memory-managed wrapper type.
DropTarget (ManagedPtr DropTarget) |
Instances
Eq DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget (==) :: DropTarget -> DropTarget -> Bool # (/=) :: DropTarget -> DropTarget -> Bool # | |
GObject DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget | |
ManagedPtrNewtype DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget toManagedPtr :: DropTarget -> ManagedPtr DropTarget | |
TypedObject DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget | |
HasParentTypes DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget | |
IsGValue (Maybe DropTarget) Source # | Convert |
Defined in GI.Gtk.Objects.DropTarget gvalueGType_ :: IO GType gvalueSet_ :: Ptr GValue -> Maybe DropTarget -> IO () gvalueGet_ :: Ptr GValue -> IO (Maybe DropTarget) | |
type ParentTypes DropTarget Source # | |
Defined in GI.Gtk.Objects.DropTarget |
class (GObject o, IsDescendantOf DropTarget o) => IsDropTarget o Source #
Type class for types which can be safely cast to DropTarget
, for instance with toDropTarget
.
Instances
(GObject o, IsDescendantOf DropTarget o) => IsDropTarget o Source # | |
Defined in GI.Gtk.Objects.DropTarget |
toDropTarget :: (MonadIO m, IsDropTarget o) => o -> m DropTarget Source #
Cast to DropTarget
, for types for which this is known to be safe. For general casts, use castTo
.
Methods
Click to display all available methods, including inherited ones
Methods
bindProperty, bindPropertyFull, forceFloating, freezeNotify, getv, isFloating, notify, notifyByPspec, ref, refSink, reject, reset, runDispose, stealData, stealQdata, thawNotify, unref, watchClosure.
Getters
getActions, getCurrentDrop, getCurrentEvent, getCurrentEventDevice, getCurrentEventState, getCurrentEventTime, getData, getDrop, getFormats, getGtypes, getName, getPreload, getPropagationLimit, getPropagationPhase, getProperty, getQdata, getValue, getWidget.
Setters
setActions, setData, setDataFull, setGtypes, setName, setPreload, setPropagationLimit, setPropagationPhase, setProperty, setStaticName.
getActions
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m [DragAction] | Returns: the actions that this drop target supports |
Gets the actions that this drop target supports.
getCurrentDrop
dropTargetGetCurrentDrop Source #
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m (Maybe Drop) | Returns: The current drop |
Gets the currently handled drop operation.
If no drop operation is going on, Nothing
is returned.
Since: 4.4
getDrop
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m (Maybe Drop) | Returns: The current drop |
Deprecated: (Since version 4.4)Use dropTargetGetCurrentDrop
instead
Gets the currently handled drop operation.
If no drop operation is going on, Nothing
is returned.
getFormats
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m (Maybe ContentFormats) | Returns: the supported data formats |
Gets the data formats that this drop target accepts.
If the result is Nothing
, all formats are expected to be supported.
getGtypes
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m (Maybe [GType]) | Returns:
the |
Gets the list of supported GType
s that can be dropped on the target.
If no types have been set, NULL
will be returned.
getPreload
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m Bool | Returns: |
Gets whether data should be preloaded on hover.
getValue
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m (Maybe GValue) | Returns: The current drop data |
Gets the current drop data, as a GValue
.
new
:: (HasCallStack, MonadIO m) | |
=> GType |
|
-> [DragAction] |
|
-> m DropTarget | Returns: the new |
Creates a new GtkDropTarget
object.
If the drop target should support more than 1 type, pass
G_TYPE_INVALID
for type
and then call
dropTargetSetGtypes
.
reject
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> m () |
Rejects the ongoing drop operation.
If no drop operation is ongoing, i.e when DropTarget:currentDrop
is Nothing
, this function does nothing.
This function should be used when delaying the decision on whether to accept a drag or not until after reading the data.
setActions
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> [DragAction] |
|
-> m () |
Sets the actions that this drop target supports.
setGtypes
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> Maybe [GType] |
|
-> m () |
Sets the supported GTypes
for this drop target.
setPreload
:: (HasCallStack, MonadIO m, IsDropTarget a) | |
=> a |
|
-> Bool |
|
-> m () |
Sets whether data should be preloaded on hover.
Properties
actions
The GdkDragActions
that this drop target supports.
constructDropTargetActions :: (IsDropTarget o, MonadIO m) => [DragAction] -> m (GValueConstruct o) Source #
Construct a GValueConstruct
with valid value for the “actions
” property. This is rarely needed directly, but it is used by new
.
getDropTargetActions :: (MonadIO m, IsDropTarget o) => o -> m [DragAction] Source #
Get the value of the “actions
” property.
When overloading is enabled, this is equivalent to
get
dropTarget #actions
setDropTargetActions :: (MonadIO m, IsDropTarget o) => o -> [DragAction] -> m () Source #
Set the value of the “actions
” property.
When overloading is enabled, this is equivalent to
set
dropTarget [ #actions:=
value ]
currentDrop
The GdkDrop
that is currently being performed.
Since: 4.4
getDropTargetCurrentDrop :: (MonadIO m, IsDropTarget o) => o -> m (Maybe Drop) Source #
Get the value of the “current-drop
” property.
When overloading is enabled, this is equivalent to
get
dropTarget #currentDrop
formats
The GdkContentFormats
that determine the supported data formats.
constructDropTargetFormats :: (IsDropTarget o, MonadIO m) => ContentFormats -> m (GValueConstruct o) Source #
Construct a GValueConstruct
with valid value for the “formats
” property. This is rarely needed directly, but it is used by new
.
getDropTargetFormats :: (MonadIO m, IsDropTarget o) => o -> m (Maybe ContentFormats) Source #
Get the value of the “formats
” property.
When overloading is enabled, this is equivalent to
get
dropTarget #formats
preload
Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.
Setting this property allows finer grained reaction to an ongoing drop at the cost of loading more data.
The default value for this property is False
to avoid downloading
huge amounts of data by accident.
For example, if somebody drags a full document of gigabytes of text from a text editor across a widget with a preloading drop target, this data will be downloaded, even if the data is ultimately dropped elsewhere.
For a lot of data formats, the amount of data is very small (like
GDK_TYPE_RGBA
), so enabling this property does not hurt at all.
And for local-only Drag-and-Drop operations, no data transfer is done,
so enabling it there is free.
constructDropTargetPreload :: (IsDropTarget o, MonadIO m) => Bool -> m (GValueConstruct o) Source #
Construct a GValueConstruct
with valid value for the “preload
” property. This is rarely needed directly, but it is used by new
.
getDropTargetPreload :: (MonadIO m, IsDropTarget o) => o -> m Bool Source #
Get the value of the “preload
” property.
When overloading is enabled, this is equivalent to
get
dropTarget #preload
setDropTargetPreload :: (MonadIO m, IsDropTarget o) => o -> Bool -> m () Source #
Set the value of the “preload
” property.
When overloading is enabled, this is equivalent to
set
dropTarget [ #preload:=
value ]
value
The value for this drop operation.
This is Nothing
if the data has not been loaded yet or no drop
operation is going on.
Data may be available before the DropTarget::drop signal gets emitted - for example when the DropTarget:preload property is set. You can use the notify signal to be notified of available data.
getDropTargetValue :: (MonadIO m, IsDropTarget o) => o -> m (Maybe GValue) Source #
Get the value of the “value
” property.
When overloading is enabled, this is equivalent to
get
dropTarget #value
Signals
accept
type DropTargetAcceptCallback Source #
Emitted on the drop site when a drop operation is about to begin.
If the drop is not accepted, False
will be returned and the drop target
will ignore the drop. If True
is returned, the drop is accepted for now
but may be rejected later via a call to dropTargetReject
or ultimately by returning False
from a DropTarget::drop
handler.
The default handler for this signal decides whether to accept the drop
based on the formats provided by the drop
.
If the decision whether the drop will be accepted or rejected depends
on the data, this function should return True
, the
DropTarget:preload property should be set and the value
should be inspected via the notify:value signal, calling
dropTargetReject
if required.
afterDropTargetAccept :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetAcceptCallback) -> m SignalHandlerId Source #
Connect a signal handler for the accept signal, to be run after the default handler. When overloading is enabled, this is equivalent to
after
dropTarget #accept callback
By default the object invoking the signal is not passed to the callback.
If you need to access it, you can use the implit ?self
parameter.
Note that this requires activating the ImplicitParams
GHC extension.
onDropTargetAccept :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetAcceptCallback) -> m SignalHandlerId Source #
Connect a signal handler for the accept signal, to be run before the default handler. When overloading is enabled, this is equivalent to
on
dropTarget #accept callback
drop
type DropTargetDropCallback Source #
= GValue |
|
-> Double |
|
-> Double |
|
-> IO Bool | Returns: whether the drop was accepted at the given pointer position |
Emitted on the drop site when the user drops the data onto the widget.
The signal handler must determine whether the pointer position is in
a drop zone or not. If it is not in a drop zone, it returns False
and no further processing is necessary.
Otherwise, the handler returns True
. In this case, this handler will
accept the drop. The handler is responsible for using the given value
and performing the drop operation.
afterDropTargetDrop :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetDropCallback) -> m SignalHandlerId Source #
Connect a signal handler for the drop signal, to be run after the default handler. When overloading is enabled, this is equivalent to
after
dropTarget #drop callback
By default the object invoking the signal is not passed to the callback.
If you need to access it, you can use the implit ?self
parameter.
Note that this requires activating the ImplicitParams
GHC extension.
onDropTargetDrop :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetDropCallback) -> m SignalHandlerId Source #
Connect a signal handler for the drop signal, to be run before the default handler. When overloading is enabled, this is equivalent to
on
dropTarget #drop callback
enter
type DropTargetEnterCallback Source #
= Double |
|
-> Double |
|
-> IO [DragAction] | Returns: Preferred action for this drag operation or 0 if
dropping is not supported at the current |
Emitted on the drop site when the pointer enters the widget.
It can be used to set up custom highlighting.
afterDropTargetEnter :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetEnterCallback) -> m SignalHandlerId Source #
Connect a signal handler for the enter signal, to be run after the default handler. When overloading is enabled, this is equivalent to
after
dropTarget #enter callback
By default the object invoking the signal is not passed to the callback.
If you need to access it, you can use the implit ?self
parameter.
Note that this requires activating the ImplicitParams
GHC extension.
onDropTargetEnter :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetEnterCallback) -> m SignalHandlerId Source #
Connect a signal handler for the enter signal, to be run before the default handler. When overloading is enabled, this is equivalent to
on
dropTarget #enter callback
leave
type DropTargetLeaveCallback = IO () Source #
Emitted on the drop site when the pointer leaves the widget.
Its main purpose it to undo things done in DropTarget::enter.
afterDropTargetLeave :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetLeaveCallback) -> m SignalHandlerId Source #
Connect a signal handler for the leave signal, to be run after the default handler. When overloading is enabled, this is equivalent to
after
dropTarget #leave callback
By default the object invoking the signal is not passed to the callback.
If you need to access it, you can use the implit ?self
parameter.
Note that this requires activating the ImplicitParams
GHC extension.
onDropTargetLeave :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetLeaveCallback) -> m SignalHandlerId Source #
Connect a signal handler for the leave signal, to be run before the default handler. When overloading is enabled, this is equivalent to
on
dropTarget #leave callback
motion
type DropTargetMotionCallback Source #
= Double |
|
-> Double |
|
-> IO [DragAction] | Returns: Preferred action for this drag operation or 0 if
dropping is not supported at the current |
Emitted while the pointer is moving over the drop target.
afterDropTargetMotion :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetMotionCallback) -> m SignalHandlerId Source #
Connect a signal handler for the motion signal, to be run after the default handler. When overloading is enabled, this is equivalent to
after
dropTarget #motion callback
By default the object invoking the signal is not passed to the callback.
If you need to access it, you can use the implit ?self
parameter.
Note that this requires activating the ImplicitParams
GHC extension.
onDropTargetMotion :: (IsDropTarget a, MonadIO m) => a -> ((?self :: a) => DropTargetMotionCallback) -> m SignalHandlerId Source #
Connect a signal handler for the motion signal, to be run before the default handler. When overloading is enabled, this is equivalent to
on
dropTarget #motion callback