Brightness Screen Filter

Question

Does anyone have an idea how to implement an Brightness Screen Filter like the one here:

http://www.appbrain.com/app/screen-filter/com.haxor

I need a starting point and I can't figure out how to do it.

Answer 1

Just make a transparent full screen activity that lets touches pass through. To make touches pass through use the following Window flags before setting the contentView:

@Override
public void onCreate(Bundle savedInstanceState)
{
  super.onCreate(savedInstanceState);
  Window window = getWindow();

  // Let touches go through to apps/activities underneath.
  window.addFlags(FLAG_NOT_TOUCHABLE);

  // Now set up content view
  setContentView(R.layout.main);
}

For your main.xml layout file just use a full screen LinearLayout with a transparent background:

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/background"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="#33000000">
</LinearLayout>

Then to adjust the "brightness" just change the value of the background colour from your code somewhere:

findViewById(R.id.background).setBackgroundColor(0x66000000);

Answer 2

• 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. layoutParams.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 3

Of course you can't use this is production code, but if you are playing around .. try this Undocumented hack

It uses :

private void setBrightness(int brightness) {
try {
  IHardwareService hardware = IHardwareService.Stub.asInterface(
   ServiceManager.getService("hardware"));
  if (hardware != null) {
    hardware.setScreenBacklight(brightness);
  }
 } catch (RemoteException doe) {          
  }        
 }

Remember that it uses this permission :

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

Answer 4

You ca try this also:

protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.max_bright);



        WindowManager.LayoutParams lp = getWindow().getAttributes();

        lp.screenBrightness = 100 / 100.0f;

        getWindow().setAttributes(lp);

    }