Callback

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The Callback API provides functions to observe the changing of device state.

Required Header

#include <device/callback.h>

Overview

The Callback API provides the way to observe the changing of device state.

This API allows observing of the following events:

• Battery capacity
• Battery level
• Battery charging
• Display state
• Flash led state

Functions
int	device_add_callback (device_callback_e type, device_changed_cb callback, void *user_data)
	Adds a callback to the observing device state.
int	device_remove_callback (device_callback_e type, device_changed_cb callback)
	Removes a device callback function.
Typedefs
typedef void(*	device_changed_cb )(device_callback_e type, void *value, void *user_data)
	Called when a device status is changed.

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Typedef Documentation

typedef void(* device_changed_cb)(device_callback_e type, void *value, void *user_data)

Called when a device status is changed.

Each device callback has a different output param type.
So you need to check below output param before using this function.
callback enum output type
DEVICE_CALLBACK_BATTERY_CAPACITY int
DEVICE_CALLBACK_BATTERY_LEVEL int
DEVICE_CALLBACK_BATTERY_CHARGING bool
DEVICE_CALLBACK_DISPLAY_STATE int
DEVICE_CALLBACK_FLASH_BRIGHTNESS int

Since :

2.3

Remarks:

DEVICE_CALLBACK_FLASH_BRIGHTNESS callback invoked when user set flash brightness by using device_flash_set_brightness(). It does not work by camera flash operation. To register DEVICE_CALLBACK_FLASH_BRIGHTNESS callback, you need to declare the LED privilege (http://tizen.org/privilege/led).

Parameters:

[out]	type	The device type to monitor
[out]	value	The changed value
[out]	user_data	The user data passed from the callback registration function

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Enumeration Type Documentation

enum device_callback_e

Enumeration for the device state callback.

Since :

2.3

Enumerator:

DEVICE_CALLBACK_BATTERY_CAPACITY	Called when a battery charge percentage is changed
DEVICE_CALLBACK_BATTERY_LEVEL	Called when a battery level is changed
DEVICE_CALLBACK_BATTERY_CHARGING	Called when battery charging state is changed
DEVICE_CALLBACK_DISPLAY_STATE	Called when a display state is changed
DEVICE_CALLBACK_FLASH_BRIGHTNESS	Called when a flash brightness is changed (Since Tizen )

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Function Documentation

int device_add_callback	(	device_callback_e	type,
		device_changed_cb	callback,
		void *	user_data
	)

Adds a callback to the observing device state.

Since :

2.3

Parameters:

[in]	type	The device type to monitor
[in]	callback	The callback function to add
[in]	user_data	The user data to be passed to the callback function

Returns:

0 on success, otherwise a negative error value

Return values:

DEVICE_ERROR_NONE	Successful
DEVICE_ERROR_INVALID_PARAMETER	Invalid parameter
DEVICE_ERROR_ALREADY_IN_PROGRESS	Operation already
DEVICE_ERROR_OPERATION_FAILED	Operation failed

int device_remove_callback	(	device_callback_e	type,
		device_changed_cb	callback
	)

Removes a device callback function.

Since :

2.3

Parameters:

[in]	type	The device type to monitor
[in]	callback	The callback function to remove

Returns:

0 on success, otherwise a negative error value

Return values:

DEVICE_ERROR_NONE	Successful
DEVICE_ERROR_INVALID_PARAMETER	Invalid parameter
DEVICE_ERROR_OPERATION_FAILED	Operation failed