轮播

-(void)scrollviewff{
   
    self.scrollview=[[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 200)];
   
     _scrollview.backgroundColor =[UIColor redColor];
   
    [self.view addSubview:_scrollview];
    _scrollview.contentSize=CGSizeMake(self.view.frame.size.width *4, 0);
   
    NSArray *imageArray= @[@"welcome1", @"welcome2",@"welcome3",@"welcome4"];
   
    for (int i=0; i<imageArray.count; i++) {
       
        UIImageView * imageView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:imageArray[i]]];
        imageView.frame =CGRectMake(i*_scrollview.frame.size.width, 0, _scrollview.frame.size.width, _scrollview.frame.size.height);
        //imageView.image=[UIImage imageNamed:imageArray[i]];
        [_scrollview addSubview:imageView];
    }
    _scrollview.pagingEnabled = YES;
    _scrollview.delegate=self;
 self.pagecontrol =[[UIPageControl alloc]initWithFrame:CGRectMake(_scrollview.center.x, 170, 60, 20)];
   self.pagecontrol.numberOfPages=imageArray.count;
self.pagecontrol.currentPageIndicatorTintColor=[UIColor redColor];
 self.pagecontrol.pageIndicatorTintColor=[UIColor blackColor];
    //关闭分见用户
   //self.pagecontrol.userInteractionEnabled =NO;
  
     [self.view addSubview:self.pagecontrol];
 
    [self addTime];
}
-(void)addTime{
    self.time = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(pagecontroldd) userInfo:nil repeats:YES];
    [[NSRunLoop mainRunLoop] addTimer:self.time forMode:NSRunLoopCommonModes];
   
   
}
-(void)removetime{
    [self.time invalidate];
    self.time=nil;
   
}
-(void)pagecontroldd{
    NSInteger currenpage =self.pagecontrol.currentPage;
    currenpage ++;
    if (currenpage==4) {
          currenpage =0;
    }
    CGFloat with =self.scrollview.frame.size.width;
    CGPoint offset= CGPointMake(currenpage*with, 0.f);
    [UIView animateWithDuration:.2f animations:^{
        self.scrollview.contentOffset=offset;
    }];
    NSLog(@"dsadfas");
   
}
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
   
    [self removetime];
   
}
-(void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{
   
    [self addTime];
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
  
    CGPoint point =scrollView.contentOffset;
    NSInteger integer =round(point.x/scrollView.frame.size.width);
   self.pagecontrol.currentPage =integer;