ohos.callback_invoke (Generic Callback Information)

Note:

Currently in the beta phase.

Import Module

import ohos.callback_invoke.*

Note:

Kit import methods are not supported and are expected to be supported in the next version.

class Callback0Argument

public abstract class Callback0Argument <: CallbackObject {}

Description: Abstract class for callback functions with no parameters.

Since: 22

Parent Type:

func invoke(?BusinessException)

public open func invoke(err: ?BusinessException): Unit

Description: Abstract class constraint requiring implementation of callback methods.

Since: 22

Parameters:

Parameter Type Required Description
err ?BusinessException Yes Exception information.

class Callback1Argument<A>

public abstract class Callback1Argument<A> <: CallbackObject {}

Description: Abstract class for callback functions with one parameter.

Since: 22

Parent Type:

func invoke(?BusinessException, A)

public open func invoke(err: ?BusinessException, arg: A): Unit

Description: Abstract class constraint requiring implementation of single-parameter callback methods.

Since: 22

Parameters:

Parameter Type Required Description
err ?BusinessException Yes Exception information.
arg A Yes Parameter required by the callback function.

class Callback1ArgumentWithReturn<A, B>

public abstract class Callback1ArgumentWithReturn<A, B> <: CallbackObject {}

Description: Abstract class for callback functions with one parameter and a return value.

Since: 22

Parent Type:

func invoke(?BusinessException, A)

public open func invoke(err: ?BusinessException, arg1: A): B

Description: Abstract class constraint requiring implementation of single-parameter callback methods.

Since: 22

Parameters:

Parameter Type Required Default Value Description
err ?BusinessException Yes - Exception information.
arg1 A Yes - Parameter required by the callback function.

Return Value:

Type Description
B Return value of the callback function.

class Callback2Argument<A, B>

public abstract class Callback2Argument<A, B> <: CallbackObject {}

Description: Abstract class for callback functions with two parameters.

Since: 22

Parent Type:

func invoke(?BusinessException, A, B)

public open func invoke(err: ?BusinessException, arg1: A, arg2: B): Unit

Description: Abstract class constraint requiring implementation of dual-parameter callback methods.

Since: 22

Parameters:

Parameter Type Required Default Value Description
err ?BusinessException Yes - Exception information.
arg1 A Yes - First parameter required by the callback function.
arg2 B Yes - Second parameter required by the callback function.

class Callback3ArgumentWithReturn<A, B, C, D>

public abstract class Callback3ArgumentWithReturn<A, B, C, D> <: CallbackObject {}

Description: Abstract class for callback functions with three parameters and a return value.

Since: 22

Parent Type:

func invoke(?BusinessException, A, B, C)

public open func invoke(err: ?BusinessException, arg1: A, arg2: B, arg3: C): D

Description: Abstract class constraint requiring implementation of three-parameter callback methods.

Since: 22

Parameters:

Parameter Type Required Default Value Description
err ?BusinessException Yes - Exception information.
arg1 A Yes - First parameter required by the callback function.
arg2 B Yes - Second parameter required by the callback function.
arg3 C Yes - Third parameter required by the callback function.

Return Value:

Type Description
D Return value of the callback function.

class CallbackObject

public abstract class CallbackObject {}

Description: Abstract base class for callback functions.

Since: 22

class CallbackWithReturn<A>

public abstract class CallbackWithReturn<A> <: CallbackObject {}

Description: Abstract class for callback functions with a return value.

Since: 22

Parent Type:

func invoke(?BusinessException)

public open func invoke(err: ?BusinessException): A

Description: Abstract class constraint requiring implementation of callback methods.

Since: 22

Parameters:

Parameter Type Required Description
err ?BusinessException Yes Exception information.

Return Value:

Type Description
A Return value of the callback function.

type Callback<T>

public type Callback<T> = (arg: T) -> Unit

Description: Callback function type.