[Android NDK] Wake lock
Posted: Thu Sep 04, 2014 12:48 pm
Wake locking the device is kinda fundamental in any game where you don't tap the display all the time. The NDK way is, as usual, quite painful and I hope my last incursion into JNI (seriously... next time, I'll just have some java code i'll be calling from the c++ side). Anyway, here it is in all it's glory
Code: Select all
// constructing the lock
JNIEnv* jni = 0;
Context->App->activity->vm->AttachCurrentThread(&jni, NULL);
if (jni)
{
jclass classNativeActivity = jni->FindClass("android/app/NativeActivity");
jclass classPowerManager = jni->FindClass("android/os/PowerManager");
if (classPowerManager)
{
jmethodID idNativeActivity_getAppContext = jni->GetMethodID(classNativeActivity, "getApplicationContext", "()Landroid/content/Context;");
jobject AppContext = jni->CallObjectMethod(Context->App->activity->clazz, idNativeActivity_getAppContext);
if (AppContext)
{
jmethodID idNativeActivity_getSystemService = jni->GetMethodID(classNativeActivity, "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;");
jstring POWER_SERVICE = jni->NewStringUTF("power");
jobject PowerManager = jni->CallObjectMethod(AppContext, idNativeActivity_getSystemService, POWER_SERVICE);
if (PowerManager)
{
jmethodID idPowerManager_newWakeLock = jni->GetMethodID(classPowerManager, "newWakeLock", "(ILjava/lang/String;)Landroid/os/PowerManager$WakeLock;");
int SCREEN_BRIGHT_WAKE_LOCK = 0x0000000a;
long int ON_AFTER_RELEASE = 0x20000000;
jstring jWakeLockTag = jni->NewStringUTF("com.entity.Polygame.MY_BRIGHT_SCREEN_LOCK_LOL");
WakeLock = jni->CallObjectMethod(PowerManager, idPowerManager_newWakeLock, SCREEN_BRIGHT_WAKE_LOCK | ON_AFTER_RELEASE, jWakeLockTag);
debugLog("constructed wake lock");
jni->DeleteLocalRef(jWakeLockTag);
}
jni->DeleteLocalRef(POWER_SERVICE);
}
}
Context->App->activity->vm->DetachCurrentThread();
}
// acquire / release (the lock is in "released" state when first constructed)
JNIEnv* jni = 0;
Context->App->activity->vm->AttachCurrentThread(&jni, NULL);
if (jni)
{
jclass wakeLock = jni->FindClass("android/os/PowerManager$WakeLock");
if (locked) to acquire the lock
{
jmethodID idWakeLock_acquire = jni->GetMethodID(wakeLock, "acquire", "()V");
jni->CallVoidMethod(WakeLock, idWakeLock_acquire);
debugLog("acquired wake lock");
}
else // release the lock
{
jmethodID idWakeLock_release = jni->GetMethodID(wakeLock, "release", "()V");
jni->CallVoidMethod(WakeLock, idWakeLock_release);
debugLog("released wake lock");
}
Context->App->activity->vm->DetachCurrentThread();
Active = locked;
}