Struct gtk4::DropTargetAsync [−][src]
pub struct DropTargetAsync(_);Expand description
DropTargetAsync is an event controller to receive Drag-and-Drop
operations, asynchronously.
It is the more complete but also more complex method of handling drop
operations compared to DropTarget, and you should only use
it if DropTarget doesn’t provide all the features you need.
To use a DropTargetAsync to receive drops on a widget, you create
a DropTargetAsync object, configure which data formats and actions
you support, connect to its signals, and then attach it to the widget
with WidgetExt::add_controller().
During a drag operation, the first signal that a DropTargetAsync
emits is signal::DropTargetAsync::accept, which is meant to determine
whether the target is a possible drop site for the ongoing drop. The
default handler for the ::accept signal accepts the drop if it finds
a compatible data format and an action that is supported on both sides.
If it is, and the widget becomes a target, you will receive a
signal::DropTargetAsync::drag-enter signal, followed by
signal::DropTargetAsync::drag-motion signals as the pointer moves,
optionally a signal::DropTargetAsync::drop signal when a drop happens,
and finally a signal::DropTargetAsync::drag-leave signal when the
pointer moves off the widget.
The ::drag-enter and ::drag-motion handler return a gdk::DragAction
to update the status of the ongoing operation. The ::drop handler
should decide if it ultimately accepts the drop and if it does, it
should initiate the data transfer and finish the operation by calling
Drop::finish().
Between the ::drag-enter and ::drag-leave signals the widget is a
current drop target, and will receive the StateFlags::DROP_ACTIVE
state, which can be used by themes to style the widget as a drop target.
Implements
Implementations
Creates a new DropTargetAsync object.
formats
the supported data formats
actions
the supported actions
Returns
the new DropTargetAsync
Creates a new builder-pattern struct instance to construct DropTargetAsync objects.
This method returns an instance of DropTargetAsyncBuilder which can be used to create DropTargetAsync objects.
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 reject_drop()
or ultimately by returning false from a signal::DropTargetAsync::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 needs
further processing, such as inspecting the data, this function should
return true and proceed as is drop was accepted and if it decides to
reject the drop later, it should call reject_drop().
drop
the gdk::Drop
Returns
true if drop is accepted
pub fn connect_drag_enter<F: Fn(&Self, &Drop, f64, f64) -> DragAction + 'static>(
&self,
f: F
) -> SignalHandlerId
pub fn connect_drag_enter<F: Fn(&Self, &Drop, f64, f64) -> DragAction + 'static>(
&self,
f: F
) -> SignalHandlerId
Emitted on the drop site when the pointer leaves the widget.
Its main purpose it to undo things done in
DropTargetAsync::drag-enter.
drop
the gdk::Drop
pub fn connect_drag_motion<F: Fn(&Self, &Drop, f64, f64) -> DragAction + 'static>(
&self,
f: F
) -> SignalHandlerId
pub fn connect_drag_motion<F: Fn(&Self, &Drop, f64, f64) -> DragAction + 'static>(
&self,
f: F
) -> SignalHandlerId
pub fn connect_drop<F: Fn(&Self, &Drop, f64, f64) -> bool + 'static>(
&self,
f: F
) -> SignalHandlerId
pub fn connect_drop<F: Fn(&Self, &Drop, f64, f64) -> bool + 'static>(
&self,
f: F
) -> SignalHandlerId
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 must ensure that Drop::finish()
is called to let the source know that the drop is done. The call to
Drop::finish() must only be done when all data has been received.
To receive the data, use one of the read functions provided by
gdk::Drop such as Drop::read_async() or
Drop::read_value_async().
drop
the gdk::Drop
x
the x coordinate of the current pointer position
y
the y coordinate of the current pointer position
Returns
whether the drop is accepted at the given pointer position
Trait Implementations
type Parent = EventController
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Returns the type identifier of Self.
Auto Trait Implementations
impl RefUnwindSafe for DropTargetAsync
impl !Send for DropTargetAsync
impl !Sync for DropTargetAsync
impl Unpin for DropTargetAsync
impl UnwindSafe for DropTargetAsync
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T. Read more
Upcasts an object to a reference of its superclass or interface T. Read more
Tries to downcast to a subclass or interface implementor T. Read more
Tries to downcast to a reference of its subclass or interface implementor T. Read more
Tries to cast to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Casts to T unconditionally. Read more
Casts to &T unconditionally. Read more
Returns true if the object is an instance of (can be cast to) T.
pub fn set_property<'a, N, V>(
&self,
property_name: N,
value: V
) -> Result<(), BoolError> where
N: Into<&'a str>,
V: ToValue,
pub fn set_property_from_value<'a, N>(
&self,
property_name: N,
value: &Value
) -> Result<(), BoolError> where
N: Into<&'a str>,
pub fn set_properties_from_value(
&self,
property_values: &[(&str, Value)]
) -> Result<(), BoolError>
pub fn has_property<'a, N>(&self, property_name: N, type_: Option<Type>) -> bool where
N: Into<&'a str>,
pub fn find_property<'a, N>(&self, property_name: N) -> Option<ParamSpec> where
N: Into<&'a str>,
Safety Read more
Safety Read more
Safety Read more
Safety Read more
pub fn connect<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
Same as connect but takes a SignalId instead of a signal name.
pub fn connect_local<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: 'static + Fn(&[Value]) -> Option<Value>,
Same as connect_local but takes a SignalId instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: Fn(&[Value]) -> Option<Value>,
Same as connect_unsafe but takes a SignalId instead of a signal name.
Emit signal by signal id.
Same as emit but takes Value for the arguments.
Emit signal by its name.
Same as emit_by_name but takes Value for the arguments.
Emit signal with details by signal id.
Same as emit_with_details but takes Value for the arguments.
pub fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
pub fn connect_notify_local<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec),
pub unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec),
pub fn bind_property<'a, O, N, M>(
&'a self,
source_property: N,
target: &'a O,
target_property: M
) -> BindingBuilder<'a> where
O: ObjectType,
N: Into<&'a str>,
M: Into<&'a str>,
Returns a SendValue clone of self.