You'd need to create a custom ImageView and override onMeasure to make the view always square.
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
SQUARE_DIMENSION = this.getMeasuredHeight(); // whatever height you want here
this.setMeasuredDimension(SQUARE_DIMENSION, SQUARE_DIMENSION);
}