Change gravity of PopupWindow

I have a button that must show a popup window. And the popup window must be aligned with the right side of the button. That's how I do it.

button.setOnClickListener( new View.OnClickListener() {
    @Override
    public void onClick( final View view ) {
        if(popup == null) {
            final View view = getLayoutInflater().inflate(R.layout.popup, null);
            popup = new PopupWindow(view);
        }

        if(popup.isShowing()) {
            popup.dismiss();
        } else {
            popup.setInputMethodMode(PopupWindow.INPUT_METHOD_NEEDED);
            popup.setFocusable(true);
            popup.setWindowLayoutMode(ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);
            popup.showAsDropDown(button, 0, 0);
        }
    }
} );

This code works fine but the popup window is aligned with the left sid开发者_StackOverflow中文版e of the button. Is there an easy way to change gravity of PopupWindow?

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The easiest way I've found is to specify the x-offset parameter:

final View view = popup.getContentView();
view.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
popup.showAsDropDown(button, button.getWidth() - view.getMeasuredWidth(), 0);

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You can try to change it from the xml file:

android:layout_graviry="left"