code: package it.mibiolab.clapp;
  
  import android.content.Context;
  import android.util.AttributeSet;
  import android.widget.ImageButton;
  
  public class SquareImageButton extends ImageButton {
  
      public SquareImageButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
          super(context, attrs, defStyleAttr, defStyleRes);
      }
  
      public SquareImageButton(Context context, AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
      }
  
      public SquareImageButton(Context context, AttributeSet attrs) {
          super(context, attrs);
      }
  
      public SquareImageButton(Context context) {
          super(context);
      }
  
      @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          super.onMeasure(widthMeasureSpec, heightMeasureSpec);
          int width=getMeasuredWidth();
          setMeasuredDimension(width,width);
      }
  }
  