Android - Turn off display without triggering sleep/lock screen - Turn on with Touchscreen

Question

I have been trying to find a way to turn off the display, and wake up from the user touching the touch screen.
The device is in an embedded environment where the device

Answer 1

You can do one thing that is Acquire Partial Wakelock and turn the Screen Off using :

PowerManager.WakeLock wl = manager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Your Tag");
wl.acquire();
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = 0;
getWindow().setAttributes(params);

Answer 2

If you have services use wake lock but if you are doing it from Activity side its better idea to use flags to acquire flag.

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); // For keeping screen on
        // You can blur screen or dim screen using following flags
        // FLAG_BLUR_BEHIND -   Blur screen
        // FLAG_DIM_BEHIND - Dim Behind

You can clear these flags like and impose other flags to dim screen or blur it. getWindow().clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

Hope this will solve your problem. Optionally Explore other flags from http://developer.android.com/reference/android/view/Window.html

There is one more Fyi.. Calling hidden API in android to turn screen off

Answer 3

Finally figured it out. Hope it helps. :)

• Get an instance of WindowManager.

  WindowManager windowManager = (WindowManager) Class.forName("android.view.WindowManagerImpl").getMethod("getDefault", new Class[0]).invoke(null, new Object[0]);

• Create a full screen layout xml(layout parameters set to fill_parent)

• Set your view as not clickable, not focusable, not long clickable, etc so that touch is passed through to your app and the app can detect it.

  view.setFocusable(false);
view.setClickable(false);
view.setKeepScreenOn(false);
view.setLongClickable(false);
view.setFocusableInTouchMode(false);

• Create a layout parameter of type android.view.WindowManager.LayoutParams. LayoutParams layoutParams = new LayoutParams();

• Set layout parameter like height, width etc

  layoutParams.height = LayoutParams.FILL_PARENT; 
  layoutParams.width = LayoutParams.FILL_PARENT;
  layoutParams.flags = 280; // You can try LayoutParams.FLAG_FULLSCREEN too
  layoutParams.format = PixelFormat.TRANSLUCENT; // You can try different formats
  layoutParams.windowAnimations = android.R.style.Animation_Toast; // You can use only animations that the system to can access
  layoutParams.type = LayoutParams.TYPE_SYSTEM_OVERLAY;
  layoutParams.gravity = Gravity.BOTTOM;
  layoutParams.x = 0;
  layoutParams.y = 0;
  layoutParams.verticalWeight = 1.0F;
  layoutParams.horizontalWeight = 1.0F;
  layoutParams.verticalMargin = 0.0F;
  layoutParams.horizontalMargin = 0.0F;
  

• Key step: You can set what percentage of brightness you need. view.setBackgroundDrawable(getBackgroundDrawable(i));

  private Drawable getBackgroundDrawable(int i) {
  int j = 255 - (int) Math.round(255D * Math.exp(4D * ((double) i / 100D) - 4D));
  return new ColorDrawable(Color.argb(j, 0, 0, 0));}
  

• Finally add view to windowManager that you created earlier.

  windowManager.addView(view, layoutParams);

Note: You need SYSTEM_ALERT_WINDOW permission to lay an overlay on the screen.

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>

Have tested this and it works. Let me know if you get stuck.

Answer 4

I don't know if that helps you but you could simply use a wake lock so your scren keeps on and display an imageview which displays a black image