Square ImageView implementation for Android.

example.xml

<com.example.SquareImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/example"
    android:scaleMode="centerCrop" />

SquareImageView.java

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ImageView;
 
public class SquareImageView extends ImageView {
 
    // Inherited constructors
 
    public SquareImageView(Context context) {
        super(context);
    }
 
    public SquareImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
 
    public SquareImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
     
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
     
        // If one of the measures is match_parent, use that one to determine the size.
        // If not, use the default implementation of onMeasure.
        if(widthMode == MeasureSpec.EXACTLY && heightMode != MeasureSpec.EXACTLY) {
            setMeasuredDimension(widthSize, widthSize);
        } else if(heightMode == MeasureSpec.EXACTLY && widthMode != MeasureSpec.EXACTLY) {
            setMeasuredDimension(heightSize, heightSize);
        } else {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    }

}