方形布局SquareLayout

public class SquareLayout extends RelativeLayout {
    public SquareLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

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

    public SquareLayout(Context context) {
        super(context);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(getDefaultSize(0, widthMeasureSpec),
                getDefaultSize(0, heightMeasureSpec));
        int childWidthSize = getMeasuredWidth();
        int childHeightSize = getMeasuredHeight();
        // 高度和宽度一样
        heightMeasureSpec = widthMeasureSpec = MeasureSpec.makeMeasureSpec(
                childWidthSize, MeasureSpec.EXACTLY);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }
}