Release a wake lock

This page describes how to release a wake lock held by your app. It's important to release a wake lock as soon as your app is finished using it to avoid draining the battery.

Release an active wake lock

To release an active wake lock, call its release() method. Doing so releases your claim to the CPU.

For example, the following code acquires a wake lock, does some work, then releases the wake lock:

Kotlin

@Throws(MyException::class)
fun doSomethingAndRelease() {
    wakeLock.apply {
        try {
            acquire(WAKELOCK_TIMEOUT)
            doTheWork()
        } finally {
            release()
        }
    }
}
WakeLockSnippetsKotlin.kt

Java

void doSomethingAndRelease() throws MyException {
    try {
        wakeLock.acquire(WAKELOCK_TIMEOUT);
        doTheWork();
    } finally {
        wakeLock.release();
    }
}
WakeLockSnippetsJava.java

Make sure to release wake locks as soon as they are no longer needed. For example, if you use a wake lock to allow a background task to finish, make sure to release the lock as soon as the task finishes.

Key points about this code

  • In this example, the method doTheWork() might throw an exception. For this reason, the code releases the wake lock in the finally block, to make sure the wake lock is released whether or not an exception is thrown. It's very important to make sure every wake lock you set is released, so you need to check every possible code path to make sure the wake lock isn't left active on any of them.

  • It's best to acquire the wake lock with WakeLock.acquire(long timeout), which automatically releases the wake lock after the specified timeout period. However, you should still release the wake lock explicitly when you no longer need it, so you don't hold the wake lock for longer than necessary.

See also