内存 过度释放

 //找回密码

    ///////////////////////////////////////////////////////

    //用类方法初始化，要用self. 否则过度是否

    self.findPassword = [UIButton buttonWithType:UIButtonTypeSystem];

    _findPassword.frame = CGRectMake(220, 350, 60, 30);

    [_findPassword setTitle:@"找回密码" forState:UIControlStateNormal];

    [self addSubview:_findPassword];