PowerManager powerManager = (PowerManager)getSystemService(POWER_SERVICE);
if (powerManager != null) {
? ? ? ? ?wakeLock = powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, "WakeLock");
?　　　　?wakeLock.acquire(); ?//開啟屏幕常亮
?　　　　//wakeLock.release(); ?//釋放wakeLock,注意此方法可能出現異常.具體可看源碼
?}

mediaPlayer.setScreenOnWhilePlaying(true);

/**
? * Control whether we should use the attached SurfaceHolder to keep the
? * screen on while video playback is occurring. ?This is the preferred
? * method over {@link #setWakeMode} where possible, since it doesn't
? * require that the application have permission for low-level wake lock
? * access.
? *
? * @param screenOn Supply true to keep the screen on, false to allow it
? * to turn off.
? */
?public void setScreenOnWhilePlaying(boolean screenOn) {
? ? ?if (mScreenOnWhilePlaying != screenOn) {
? ? ? ? ?if (screenOn && mSurfaceHolder == null) {
? ? ? ? ? ? ?Log.w(TAG, "setScreenOnWhilePlaying(true) is ineffective without a SurfaceHolder");
? ? ? ? ?}
? ? ? ? ?mScreenOnWhilePlaying = screenOn;
? ? ? ? ?updateSurfaceScreenOn();
? ? ?}
?}
　　......

?private void updateSurfaceScreenOn() {
? ? ?if (mSurfaceHolder != null) {　　　　　　??
? ? ? ? ?mSurfaceHolder.setKeepScreenOn(mScreenOnWhilePlaying && mStayAwake); ??
? ? ?}
?}

/**
* 是否開啟屏幕常亮
?*/
private var enableKeepScreenOn = false

/**
?* activity 生命周期監聽器
?*/
private var mActivityLifecycleCallbacks = object : Application.ActivityLifecycleCallbacks {
? ? override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) {
? ? ? ? //在activity創建的時候設置屏幕保持常亮
? ? ? ? if (enableKeepScreenOn) {
? ? ? ? ? ? activity.window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
? ? ? ? }
? ? }

? ? override fun onActivityStarted(activity: Activity) {
? ? }

? ? override fun onActivityResumed(activity: Activity) {
? ? }

? ? override fun onActivityPaused(activity: Activity) {
? ? }

? ? override fun onActivityStopped(activity: Activity) {
? ? }

? ? override fun onActivitySaveInstanceState(activity: Activity, outState: Bundle) {
? ? }

? ? override fun onActivityDestroyed(activity: Activity) {
? ? }

}

/**
?* 設置保持屏幕常亮狀態
?*/
fun setKeepScreenOn(enable: Boolean) {
?? ?enableKeepScreenOn = enable
}