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 is a tablet and the user does not have access to anything except the touch screen (no buttons at all).
It is connected to power so the battery won't be a problem, but when I detect no activity I want to turn off the screen so it isn't staring them in the face all day and doesn't reduce the life the LCD backlight.
I maintain a wakelock permanently and decide when to sleep myself.
The problem is that when I turn off the screen using :
WindowManager.LayoutParams params = getWindow().getAttributes(); params.screenBrightness = 0; getWindow().setAttributes(params);
The activity gets paused and stopped. And the unit does not respond to a touch to wake it up. You need to press the power button. At that point the "slide to unlock" shows up.
I want to turn off the display, and then stay running so I can detect a touch screen event and turn the display back on.
I also tried turning the display to a brightness of 0.1, which works on some devices, but the device I need it to work on, only "dims" the display.
I also tried this:
// First Remove my FULL wakelock //then aquire a partial wake lock (which should turn off the display) PowerManager.WakeLock wl = manager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Your Tag"); wl.acquire();
however this method does not turn off the display.
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.
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