怎样点击按钮打开一个xib创建的界面解决方法

#import "SwitchViewCtl.h"@implementation SwitchViewCtl-(id)init{    if (self=[super init]) {        v1 = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 400, 400)];        v2 = [[UIView alloc] initWithFrame:CGRectMake(0, 500, 400, 600)];        //先初始化两个View                [v1 setBackgroundColor:[UIColor cyanColor]];        UIButton *bt = [[UIButton alloc] initWithFrame:CGRectMake(100, 250, 100, 50)];        [bt setImage:[UIImage imageNamed:@"114.png"] forState:UIControlStateNormal];        bt.titleLabel.text = @"显 示";        [bt addTarget:self action:@selector(openView) forControlEvents:UIControlEventTouchDown];        [v1 addSubview:bt];        [self.view addSubview:v1];//加载一个    }    return self;}-(void)openView{    v1.hidden=YES;//可以先隐藏之，也可以设置Frame覆盖掉，当然还可以，从主ViewCtl中删除 [v1 removeFromSuperview];        [v2 setBackgroundColor:[UIColor blueColor]];    [self.view addSubview:v2];//加载另一个    [self.view setNeedsDisplay];//这里是刷新啦}