Keep aspect ratio to 1:1. Not tested.

SqaureFrameLayout.java

package net.ypresto.utils.squareview;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.FrameLayout;

/**
 * FrameLayout enforces its aspect ratio to 1:1.
 * NOTE: wrap_content is not supported.
 */
public class SqaureFrameLayout extends FrameLayout {
    public SqaureFrameLayout(Context context) {
        super(context);
    }

    public SqaureFrameLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public SqaureFrameLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        boolean isWidthUnspecified = MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.UNSPECIFIED;
        boolean isHeightUnspecified = MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED;
        if (isWidthUnspecified && isHeightUnspecified) {
            // Unsupported
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
            return;
        }

        int width = isWidthUnspecified ? Integer.MAX_VALUE : MeasureSpec.getSize(widthMeasureSpec);
        int height = isHeightUnspecified ? Integer.MAX_VALUE : MeasureSpec.getSize(heightMeasureSpec);
        int measureSpec = MeasureSpec.makeMeasureSpec(Math.min(width, height), MeasureSpec.EXACTLY);
        super.onMeasure(measureSpec, measureSpec);
    }
}