UIScrollView配合定时器自动循环滚动

@property (strong,
nonatomic) UIScrollView *scrollView;

@property (strong,
nonatomic)UIPageControl *pageControl;

//定时器

@property(strong,nonatomic)NSTimer * timer;

- (void)viewDidLoad {

[super
viewDidLoad];

_timeIndex=0;

_timer = [NSTimer
scheduledTimerWithTimeInterval:3
target:self
selector:@selector(scrollChange)
userInfo:nil
repeats:YES];
}

//定时器执行方法
-(void)scrollChange
{

_timeIndex++;

if (_timeIndex ==
5) {

// NSLog(@"_timeIndex = %ld",_timeIndex);

_timeIndex = 1;

_scrollView.contentOffset =
CGPointMake(WIDTH *
_timeIndex, 0);
}else
if(_timeIndex ==
6)
{

_timeIndex = 3;

_scrollView.contentOffset =
CGPointMake(WIDTH *
_timeIndex, 0);
}

else {

_scrollView.contentOffset =
CGPointMake(_timeIndex *WIDTH,0);
}
}

//将开始拖拽时使定时器停止
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{

NSLog(@"1");

[_timer
invalidate];

_timer = nil;
}

//拖拽结束时再开启定时器
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{

NSLog(@"@@");

_timeIndex = scrollView.contentOffset.x/WIDTH ;

NSLog(@"_timeIndex = %ld",_timeIndex);

_timer = [NSTimer
scheduledTimerWithTimeInterval:3
target:self
selector:@selector(scrollChange)
userInfo:nil
repeats:YES];
}

//scrollview发生变动时调用此方法,多次调用
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//防止同一个view上其他的scrollview同时调用此方法

if (scrollView.tag ==200) {

UIPageControl * pc = (UIPageControl *)[self.view
viewWithTag:10];

// _timeIndex++;

int currentPage =scrollView.contentOffset.x/WIDTH;

// NSLog(@"currentPage = %d",currentPage);

if (currentPage >
5) {

_scrollView.contentOffset =
CGPointMake(WIDTH *
2, 0);
}
else if (currentPage<1) {

_scrollView.contentOffset =
CGPointMake(4*WIDTH,0);
pc.currentPage =
4;
}

if (currentPage >0 && currentPage <
5) {
pc.currentPage = currentPage-1;
}else
if (currentPage ==
5)
{
pc.currentPage =
0;
}else
if (currentPage ==
6)
{
pc.currentPage =
1;
}else
if(currentPage ==
0)
{
pc.currentPage =
3;
}
}
}