java.lang.Object

   ↳ android.os.PowerManager

Nested classes

interface PowerManager.OnThermalStatusChangedListener

Listener passed to PowerManager#addThermalStatusListener and PowerManager#removeThermalStatusListener to notify caller of thermal status has changed. 

class PowerManager.WakeLock

A wake lock is a mechanism to indicate that your application needs to have the device stay on. 

Constants

int ACQUIRE_CAUSES_WAKEUP

Wake lock flag: Turn the screen on when the wake lock is acquired.

String ACTION_DEVICE_IDLE_MODE_CHANGED

Intent that is broadcast when the state of isDeviceIdleMode() changes.

String ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED

Intent that is broadcast when the state of isDeviceLightIdleMode() changes.

String ACTION_POWER_SAVE_MODE_CHANGED

Intent that is broadcast when the state of isPowerSaveMode() changes.

int FULL_WAKE_LOCK

This constant was deprecated in API level 17. Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

int LOCATION_MODE_ALL_DISABLED_WHEN_SCREEN_OFF

All location providers should be disabled when battery saver is on and the device is non-interactive.

int LOCATION_MODE_FOREGROUND_ONLY

In this mode, all the location providers will be kept available, but location fixes should only be provided to foreground apps.

int LOCATION_MODE_GPS_DISABLED_WHEN_SCREEN_OFF

In this mode, the GPS based location provider should be disabled when battery saver is on and the device is non-interactive.

int LOCATION_MODE_NO_CHANGE

Either the location providers shouldn't be affected by battery saver, or battery saver is off.

int LOCATION_MODE_THROTTLE_REQUESTS_WHEN_SCREEN_OFF

In this mode, location will not be turned off, but LocationManager will throttle all requests to providers when the device is non-interactive.

int ON_AFTER_RELEASE

Wake lock flag: When this wake lock is released, poke the user activity timer so the screen stays on for a little longer.

int PARTIAL_WAKE_LOCK

Wake lock level: Ensures that the CPU is running; the screen and keyboard backlight will be allowed to go off.

int PROXIMITY_SCREEN_OFF_WAKE_LOCK

Wake lock level: Turns the screen off when the proximity sensor activates.

int RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY

Flag for WakeLock.release(int): Defer releasing a PROXIMITY_SCREEN_OFF_WAKE_LOCK wake lock until the proximity sensor indicates that an object is not in close proximity.

int SCREEN_BRIGHT_WAKE_LOCK

This constant was deprecated in API level 15. Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

int SCREEN_DIM_WAKE_LOCK

This constant was deprecated in API level 17. Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

int THERMAL_STATUS_CRITICAL

Thermal status code: Platform has done everything to reduce power.

int THERMAL_STATUS_EMERGENCY

Thermal status code: Key components in platform are shutting down due to thermal condition.

int THERMAL_STATUS_LIGHT

Thermal status code: Light throttling where UX is not impacted.

int THERMAL_STATUS_MODERATE

Thermal status code: Moderate throttling where UX is not largely impacted.

int THERMAL_STATUS_NONE

Thermal status code: Not under throttling.

int THERMAL_STATUS_SEVERE

Thermal status code: Severe throttling where UX is largely impacted.

int THERMAL_STATUS_SHUTDOWN

Thermal status code: Need shutdown immediately.

Public methods

void addThermalStatusListener(Executor executor, PowerManager.OnThermalStatusChangedListener listener)

This function adds a listener for thermal status change.

void addThermalStatusListener(PowerManager.OnThermalStatusChangedListener listener)

This function adds a listener for thermal status change, listen call back will be enqueued tasks on the main thread

Duration getBatteryDischargePrediction()

Returns the current battery life remaining estimate.

int getCurrentThermalStatus()

This function returns the current thermal status of the device.

int getLocationPowerSaveMode()

Returns how location features should behave when battery saver is on.

float getThermalHeadroom(int forecastSeconds)

Provides an estimate of how much thermal headroom the device currently has before hitting severe throttling.

boolean isBatteryDischargePredictionPersonalized()

Returns whether the current battery life remaining estimate is personalized based on device usage history or not.

boolean isDeviceIdleMode()

Returns true if the device is currently in idle mode.

boolean isDeviceLightIdleMode()

Returns true if the device is currently in light idle mode.

boolean isIgnoringBatteryOptimizations(String packageName)

Return whether the given application package name is on the device's power allowlist.

boolean isInteractive()

Returns true if the device is in an interactive state.

boolean isPowerSaveMode()

Returns true if the device is currently in power save mode.

boolean isRebootingUserspaceSupported()

Returns true if this device supports rebooting userspace.

boolean isScreenOn()

This method was deprecated in API level 20. Use isInteractive() instead.

boolean isSustainedPerformanceModeSupported()

This function checks if the device has implemented Sustained Performance Mode.

boolean isWakeLockLevelSupported(int level)

Returns true if the specified wake lock level is supported.

PowerManager.WakeLock newWakeLock(int levelAndFlags, String tag)

Creates a new wake lock with the specified level and flags.

void reboot(String reason)

Reboot the device.

void removeThermalStatusListener(PowerManager.OnThermalStatusChangedListener listener)

This function removes a listener for thermal status change

Inherited methods

From class java.lang.Object

ACQUIRE_CAUSES_WAKEUP

public static final int ACQUIRE_CAUSES_WAKEUP

Wake lock flag: Turn the screen on when the wake lock is acquired.

Normally wake locks don't actually wake the device, they just cause the screen to remain on once it's already on. Think of the video player application as the normal behavior. Notifications that pop up and want the device to be on are the exception; use this flag to be like them.

Android TV playback devices attempt to turn on the HDMI-connected TV via HDMI-CEC on any wake-up, including wake-ups triggered by wake locks.

Cannot be used with PARTIAL_WAKE_LOCK.

Constant Value: 268435456 (0x10000000)

ACTION_DEVICE_IDLE_MODE_CHANGED

public static final String ACTION_DEVICE_IDLE_MODE_CHANGED

Intent that is broadcast when the state of isDeviceIdleMode() changes. This broadcast is only sent to registered receivers.

Constant Value: "android.os.action.DEVICE_IDLE_MODE_CHANGED"

ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED

public static final String ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED

Intent that is broadcast when the state of isDeviceLightIdleMode() changes. This broadcast is only sent to registered receivers.

Constant Value: "android.os.action.LIGHT_DEVICE_IDLE_MODE_CHANGED"

ACTION_POWER_SAVE_MODE_CHANGED

public static final String ACTION_POWER_SAVE_MODE_CHANGED

Intent that is broadcast when the state of isPowerSaveMode() changes. This broadcast is only sent to registered receivers.

Constant Value: "android.os.action.POWER_SAVE_MODE_CHANGED"

FULL_WAKE_LOCK

public static final int FULL_WAKE_LOCK

This constant was deprecated in API level 17.
Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

Wake lock level: Ensures that the screen and keyboard backlight are on at full brightness.

If the user presses the power button, then the FULL_WAKE_LOCK will be implicitly released by the system, causing both the screen and the CPU to be turned off. Contrast with PARTIAL_WAKE_LOCK.

Constant Value: 26 (0x0000001a)

LOCATION_MODE_ALL_DISABLED_WHEN_SCREEN_OFF

public static final int LOCATION_MODE_ALL_DISABLED_WHEN_SCREEN_OFF

All location providers should be disabled when battery saver is on and the device is non-interactive.

Constant Value: 2 (0x00000002)

LOCATION_MODE_FOREGROUND_ONLY

public static final int LOCATION_MODE_FOREGROUND_ONLY

In this mode, all the location providers will be kept available, but location fixes should only be provided to foreground apps.

Constant Value: 3 (0x00000003)

LOCATION_MODE_GPS_DISABLED_WHEN_SCREEN_OFF

public static final int LOCATION_MODE_GPS_DISABLED_WHEN_SCREEN_OFF

In this mode, the GPS based location provider should be disabled when battery saver is on and the device is non-interactive.

Constant Value: 1 (0x00000001)

LOCATION_MODE_NO_CHANGE

public static final int LOCATION_MODE_NO_CHANGE

Either the location providers shouldn't be affected by battery saver, or battery saver is off.

Constant Value: 0 (0x00000000)

LOCATION_MODE_THROTTLE_REQUESTS_WHEN_SCREEN_OFF

public static final int LOCATION_MODE_THROTTLE_REQUESTS_WHEN_SCREEN_OFF

In this mode, location will not be turned off, but LocationManager will throttle all requests to providers when the device is non-interactive.

Constant Value: 4 (0x00000004)

ON_AFTER_RELEASE

public static final int ON_AFTER_RELEASE

Wake lock flag: When this wake lock is released, poke the user activity timer so the screen stays on for a little longer.

Will not turn the screen on if it is not already on. See ACQUIRE_CAUSES_WAKEUP if you want that.

Cannot be used with PARTIAL_WAKE_LOCK.

Constant Value: 536870912 (0x20000000)

PARTIAL_WAKE_LOCK

public static final int PARTIAL_WAKE_LOCK

Wake lock level: Ensures that the CPU is running; the screen and keyboard backlight will be allowed to go off.

If the user presses the power button, then the screen will be turned off but the CPU will be kept on until all partial wake locks have been released.

Constant Value: 1 (0x00000001)

PROXIMITY_SCREEN_OFF_WAKE_LOCK

public static final int PROXIMITY_SCREEN_OFF_WAKE_LOCK

Wake lock level: Turns the screen off when the proximity sensor activates.

If the proximity sensor detects that an object is nearby, the screen turns off immediately. Shortly after the object moves away, the screen turns on again.

A proximity wake lock does not prevent the device from falling asleep unlike FULL_WAKE_LOCK, SCREEN_BRIGHT_WAKE_LOCK and SCREEN_DIM_WAKE_LOCK. If there is no user activity and no other wake locks are held, then the device will fall asleep (and lock) as usual. However, the device will not fall asleep while the screen has been turned off by the proximity sensor because it effectively counts as ongoing user activity.

Since not all devices have proximity sensors, use isWakeLockLevelSupported(int) to determine whether this wake lock level is supported.

Cannot be used with ACQUIRE_CAUSES_WAKEUP.

Constant Value: 32 (0x00000020)

RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY

public static final int RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY

Flag for WakeLock.release(int): Defer releasing a PROXIMITY_SCREEN_OFF_WAKE_LOCK wake lock until the proximity sensor indicates that an object is not in close proximity.

Constant Value: 1 (0x00000001)

SCREEN_BRIGHT_WAKE_LOCK

public static final int SCREEN_BRIGHT_WAKE_LOCK

This constant was deprecated in API level 15.
Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

Wake lock level: Ensures that the screen is on at full brightness; the keyboard backlight will be allowed to go off.

If the user presses the power button, then the SCREEN_BRIGHT_WAKE_LOCK will be implicitly released by the system, causing both the screen and the CPU to be turned off. Contrast with PARTIAL_WAKE_LOCK.

Constant Value: 10 (0x0000000a)

SCREEN_DIM_WAKE_LOCK

public static final int SCREEN_DIM_WAKE_LOCK

This constant was deprecated in API level 17.
Most applications should use WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will be correctly managed by the platform as the user moves between applications and doesn't require a special permission.

Wake lock level: Ensures that the screen is on (but may be dimmed); the keyboard backlight will be allowed to go off.

If the user presses the power button, then the SCREEN_DIM_WAKE_LOCK will be implicitly released by the system, causing both the screen and the CPU to be turned off. Contrast with PARTIAL_WAKE_LOCK.

Constant Value: 6 (0x00000006)

THERMAL_STATUS_CRITICAL

public static final int THERMAL_STATUS_CRITICAL

Thermal status code: Platform has done everything to reduce power.

Constant Value: 4 (0x00000004)

THERMAL_STATUS_EMERGENCY

public static final int THERMAL_STATUS_EMERGENCY

Thermal status code: Key components in platform are shutting down due to thermal condition. Device functionalities will be limited.

Constant Value: 5 (0x00000005)

THERMAL_STATUS_LIGHT

public static final int THERMAL_STATUS_LIGHT

Thermal status code: Light throttling where UX is not impacted.

Constant Value: 1 (0x00000001)

THERMAL_STATUS_MODERATE

public static final int THERMAL_STATUS_MODERATE

Thermal status code: Moderate throttling where UX is not largely impacted.

Constant Value: 2 (0x00000002)

THERMAL_STATUS_NONE

public static final int THERMAL_STATUS_NONE

Thermal status code: Not under throttling.

Constant Value: 0 (0x00000000)

THERMAL_STATUS_SEVERE

public static final int THERMAL_STATUS_SEVERE

Thermal status code: Severe throttling where UX is largely impacted.

Constant Value: 3 (0x00000003)

THERMAL_STATUS_SHUTDOWN

public static final int THERMAL_STATUS_SHUTDOWN

Thermal status code: Need shutdown immediately.

Constant Value: 6 (0x00000006)

addThermalStatusListener

public void addThermalStatusListener (Executor executor, 
                PowerManager.OnThermalStatusChangedListener listener)

This function adds a listener for thermal status change.

addThermalStatusListener

public void addThermalStatusListener (PowerManager.OnThermalStatusChangedListener listener)

This function adds a listener for thermal status change, listen call back will be enqueued tasks on the main thread

getBatteryDischargePrediction

public Duration getBatteryDischargePrediction ()

Returns the current battery life remaining estimate.

getCurrentThermalStatus

public int getCurrentThermalStatus ()

This function returns the current thermal status of the device.

getLocationPowerSaveMode

public int getLocationPowerSaveMode ()

Returns how location features should behave when battery saver is on. When battery saver is off, this will always return LOCATION_MODE_NO_CHANGE.

This API is normally only useful for components that provide location features.

getThermalHeadroom

public float getThermalHeadroom (int forecastSeconds)

Provides an estimate of how much thermal headroom the device currently has before hitting severe throttling.

Note that this only attempts to track the headroom of slow-moving sensors, such as the skin temperature sensor. This means that there is no benefit to calling this function more frequently than about once per second, and attempts to call significantly more frequently may result in the function returning NaN.

In addition, in order to be able to provide an accurate forecast, the system does not attempt to forecast until it has multiple temperature samples from which to extrapolate. This should only take a few seconds from the time of the first call, but during this time, no forecasting will occur, and the current headroom will be returned regardless of the value of forecastSeconds.

The value returned is a non-negative float that represents how much of the thermal envelope is in use (or is forecasted to be in use). A value of 1.0 indicates that the device is (or will be) throttled at THERMAL_STATUS_SEVERE. Such throttling can affect the CPU, GPU, and other subsystems. Values may exceed 1.0, but there is no implied mapping to specific thermal status levels beyond that point. This means that values greater than 1.0 may correspond to THERMAL_STATUS_SEVERE, but may also represent heavier throttling.

A value of 0.0 corresponds to a fixed distance from 1.0, but does not correspond to any particular thermal status or temperature. Values on (0.0, 1.0] may be expected to scale linearly with temperature, though temperature changes over time are typically not linear. Negative values will be clamped to 0.0 before returning.

isBatteryDischargePredictionPersonalized

public boolean isBatteryDischargePredictionPersonalized ()

Returns whether the current battery life remaining estimate is personalized based on device usage history or not. This value does not take a device's powered or charging state into account.

isDeviceIdleMode

public boolean isDeviceIdleMode ()

Returns true if the device is currently in idle mode. This happens when a device has been sitting unused and unmoving for a sufficiently long period of time, so that it decides to go into a lower power-use state. This may involve things like turning off network access to apps. You can monitor for changes to this state with ACTION_DEVICE_IDLE_MODE_CHANGED.

isDeviceLightIdleMode

public boolean isDeviceLightIdleMode ()

Returns true if the device is currently in light idle mode. This happens when a device has had its screen off for a short time, switching it into a batching mode where we execute jobs, syncs, networking on a batching schedule. You can monitor for changes to this state with ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED.

isIgnoringBatteryOptimizations

public boolean isIgnoringBatteryOptimizations (String packageName)

Return whether the given application package name is on the device's power allowlist. Apps can be placed on the allowlist through the settings UI invoked by Settings.ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS.

Being on the power allowlist means that the system will not apply most power saving features to the app. Guardrails for extreme cases may still be applied.

isInteractive

public boolean isInteractive ()

Returns true if the device is in an interactive state.

When this method returns true, the device is awake and ready to interact with the user (although this is not a guarantee that the user is actively interacting with the device just this moment). The main screen is usually turned on while in this state. Certain features, such as the proximity sensor, may temporarily turn off the screen while still leaving the device in an interactive state. Note in particular that the device is still considered to be interactive while dreaming (since dreams can be interactive) but not when it is dozing or asleep.

When this method returns false, the device is dozing or asleep and must be awoken before it will become ready to interact with the user again. The main screen is usually turned off while in this state. Certain features, such as "ambient mode" may cause the main screen to remain on (albeit in a low power state) to display system-provided content while the device dozes.

The system will send a screen on or screen off broadcast whenever the interactive state of the device changes. For historical reasons, the names of these broadcasts refer to the power state of the screen but they are actually sent in response to changes in the overall interactive state of the device, as described by this method.

Services may use the non-interactive state as a hint to conserve power since the user is not present.

isPowerSaveMode

public boolean isPowerSaveMode ()

Returns true if the device is currently in power save mode. When in this mode, applications should reduce their functionality in order to conserve battery as much as possible. You can monitor for changes to this state with ACTION_POWER_SAVE_MODE_CHANGED.

isRebootingUserspaceSupported

public boolean isRebootingUserspaceSupported ()

Returns true if this device supports rebooting userspace.

isScreenOn

public boolean isScreenOn ()

This method was deprecated in API level 20.
Use isInteractive() instead.

Returns true if the device is in an interactive state.

For historical reasons, the name of this method refers to the power state of the screen but it actually describes the overall interactive state of the device. This method has been replaced by isInteractive().

The value returned by this method only indicates whether the device is in an interactive state which may have nothing to do with the screen being on or off. To determine the actual state of the screen, use Display.getState().

isSustainedPerformanceModeSupported

public boolean isSustainedPerformanceModeSupported ()

This function checks if the device has implemented Sustained Performance Mode. This needs to be checked only once and is constant for a particular device/release.

Sustained Performance Mode is intended to provide a consistent level of performance for prolonged amount of time.

Applications should check if the device supports this mode, before using Window.setSustainedPerformanceMode(boolean).

isWakeLockLevelSupported

public boolean isWakeLockLevelSupported (int level)

Returns true if the specified wake lock level is supported.

newWakeLock

public PowerManager.WakeLock newWakeLock (int levelAndFlags, 
                String tag)

Creates a new wake lock with the specified level and flags.

The levelAndFlags parameter specifies a wake lock level and optional flags combined using the logical OR operator.

The wake lock levels are: PARTIAL_WAKE_LOCK, FULL_WAKE_LOCK, SCREEN_DIM_WAKE_LOCK and SCREEN_BRIGHT_WAKE_LOCK. Exactly one wake lock level must be specified as part of the levelAndFlags parameter.

The wake lock flags are: ACQUIRE_CAUSES_WAKEUP and ON_AFTER_RELEASE. Multiple flags can be combined as part of the levelAndFlags parameters.

Call acquire() on the object to acquire the wake lock, and release() when you are done.

PowerManager pm = mContext.getSystemService(PowerManager.class);
 PowerManager.WakeLock wl = pm.newWakeLock(
                                      PowerManager.SCREEN_DIM_WAKE_LOCK
                                      | PowerManager.ON_AFTER_RELEASE,
                                      TAG);
 wl.acquire();
 // ... do work...
 wl.release();
 

Although a wake lock can be created without special permissions, the Manifest.permission.WAKE_LOCK permission is required to actually acquire or release the wake lock that is returned.

If using this to keep the screen on, you should strongly consider using WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON instead. This window flag will be correctly managed by the platform as the user moves between applications and doesn't require a special permission. Additionally using the flag will keep only the appropriate screen on in a multi-display scenario while using a wake lock will keep every screen powered on.

Recommended naming conventions for tags to make debugging easier:

• use a unique prefix delimited by a colon for your app/library (e.g. gmail:mytag) to make it easier to understand where the wake locks comes from. This namespace will also avoid collision for tags inside your app coming from different libraries which will make debugging easier.
• use constants (e.g. do not include timestamps in the tag) to make it easier for tools to aggregate similar wake locks. When collecting debugging data, the platform only monitors a finite number of tags, using constants will help tools to provide better debugging data.
• avoid using Class#getName() or similar method since this class name can be transformed by java optimizer and obfuscator tools.
• avoid wrapping the tag or a prefix to avoid collision with wake lock tags from the platform (e.g. *alarm*).
• never include personally identifiable information for privacy reasons.

reboot

public void reboot (String reason)

Reboot the device. Will not return if the reboot is successful.

Requires the Manifest.permission.REBOOT permission.

If the reason string contains ",quiescent", then the screen stays off during reboot and is not turned on again until the user triggers the device to wake up (for example, by pressing the power key). This behavior applies to Android TV devices launched on Android 11 (API level 30) or higher.

Requires Manifest.permission.REBOOT

removeThermalStatusListener

public void removeThermalStatusListener (PowerManager.OnThermalStatusChangedListener listener)

This function removes a listener for thermal status change