PopWindow Android 7.0 位置显示不准确解决办法

popWindow 在Android7.0上的显示位置不管怎么设置都在屏幕的顶部，这是7.0的bug，已在7.1修复，但是7.0还是需要我们自己解决的，方法如下：

      @Override
    public void showAsDropDown(View anchorView, int xoff, int yoff) {
        if (Build.VERSION.SDK_INT == Build.VERSION_CODES.N) {
            int[] a = new int[2];
            anchorView.getLocationInWindow(a);
            showAtLocation(anchorView, Gravity.NO_GRAVITY, xoff, a[1] + anchorView.getHeight() + yoff);
        } else {
            super.showAsDropDown(anchorView, xoff, yoff);
        }
    }

     @Override
    public void showAsDropDown(View anchorView) {
        if (Build.VERSION.SDK_INT == Build.VERSION_CODES.N) {
            int[] a = new int[2];
            anchorView.getLocationInWindow(a);
            showAtLocation(anchorView, Gravity.NO_GRAVITY, 0, a[1] + anchorView.getHeight() + 0);
        } else {
            super.showAsDropDown(anchorView);
        }
    }