button.contentHorizontalAlignment // 对齐属性
对齐类型
/*
UIControlContentHorizontalAlignmentCenter =0,*/
UIControlContentHorizontalAlignmentLeft=1,
UIControlContentHorizontalAlignmentRight=2,
UIControlContentHorizontalAlignmentFill=3,
*/
/*
UIControlContentHorizontalAlignmentCenter =0,*/
UIControlContentHorizontalAlignmentLeft=1,
UIControlContentHorizontalAlignmentRight=2,
UIControlContentHorizontalAlignmentFill=3,
*/