Back pressed events with system alert window

Question

I need to dismiss system alert window on back pressed and home button event.I have tried with onKeyEvent but in vain. As we can't capture the back pressed event in a service, how to achieve this?

Answer 1

Since it's a service that hosting an overlay window, It's a bit tricky solution but it is possible.

You should handle these 2 cases separately (overriding home button press, and back button press).

---

1. Overriding home button press:

Create this HomeWatcher class which contains a BroadcastReceiver that will notify when home button was pressed. Register this receiver only when your window comes up.

Android: associate a method to home button of smartphone

Inside your service onCreate method use this:

HomeWatcher mHomeWatcher = new HomeWatcher(this);
mHomeWatcher.setOnHomePressedListener(new OnHomePressedListener() {
    @Override
    public void onHomePressed() {
        yourWindow.hide()  //means: windowManager.removeView(view);
    }
    @Override
    public void onHomeLongPressed() {
    }
});
mHomeWatcher.startWatch();

---

2. Overriding back button press:

The idea is creating an empty layout as a data member of your window class, and attach your view to it (even if its an inflated XML layout).

For example, this is gonna be your window class:

public class MyWindow
{
    private WindowManager windowManager;
    private WindowManager.LayoutParams params;
    private View view;

    // Add this empty layout:
    private MyLayout myLayout;

    public MyWindow()
    {
        windowManager = (WindowManager) context.getSystemService(context.WINDOW_SERVICE);
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.your_original_window_layout, null);

        // Add your original view to the new empty layout:
        myLayout = new MyLayout(this);
        myLayout.addView(view, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
    }

    // And show this layout instead of your original view:
    public void show()
    {
        windowManager.addView(myLayout, params);
    }

    public void hide()
    {
        windowManager.removeView(myLayout);
    }
}

And now create the MyLayout class to override the back button press:

public class MyLayout extends LinearLayout
{
    private MyWindow myWindow;

    public MyLayout(MyWindow myWindow)
    {
        super(myWindow.context);

        this.myWindow = myWindow;
    }


    @Override public boolean dispatchKeyEvent(KeyEvent event)
    {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK)
        {
            if (event.getAction() == KeyEvent.ACTION_DOWN  &&  event.getRepeatCount() == 0)
            {
                getKeyDispatcherState().startTracking(event, this);
                return true;

            }

            else if (event.getAction() == KeyEvent.ACTION_UP)
            {
                getKeyDispatcherState().handleUpEvent(event);

                if (event.isTracking() && !event.isCanceled())
                {
                    // dismiss your window:
                    myWindow.hide();

                    return true;
                }
            }
        }

        return super.dispatchKeyEvent(event);
    }
}

I know it's a bit complicated as I said since it's a system alert window hosted by a service, BUT it's working. I have the same issue as well and it has been solved exactly like that. Good luck.