如何使用 NSTimer 使 UICollectionView 自动滚动？

Question

如何使用 NSTimer 在水平位置自动滚动 UIcollectionView

我正在处理我的项目源代码如下：

- (void)viewDidLoad {
    [super viewDidLoad];

    self.endPoint = CGPointMake(0, self.collectionView.frame.size.width);
    self.scrollingPoint = CGPointMake(0, 0);
    self.scrollingTimer = [NSTimer scheduledTimerWithTimeInterval:0.015 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];

}

- (void)onTimer {
     self.collectionView.contentOffset = self.scrollingPoint;
    if (CGPointEqualToPoint(self.scrollingPoint, self.endPoint)) {
        [self.scrollingTimer invalidate];
    }
    self.scrollingPoint = CGPointMake(self.scrollingPoint.x+1, 0);
}

尝试使用上面的代码，但对我不起作用。

Answer 1

斯威夫特 4.2

带有 Runloop 和 Timer 块。调整 0.015 和 0.25 值以匹配您所需的速度。

    var carousalTimer: Timer?
    var newOffsetX: CGFloat = 0.0
    func startTimer() {

        carousalTimer = Timer(fire: Date(), interval: 0.015, repeats: true) { (timer) in

            let initailPoint = CGPoint(x: self.newOffsetX,y :0)

            if __CGPointEqualToPoint(initailPoint, self.collectionView.contentOffset) {

                if self.newOffsetX < self.collectionView.contentSize.width {
                    self.newOffsetX += 0.25
                }
                if self.newOffsetX > self.collectionView.contentSize.width - self.collectionView.frame.size.width {
                    self.newOffsetX = 0
                }

                self.collectionView.contentOffset = CGPoint(x: self.newOffsetX,y :0)

            } else {
                self.newOffsetX = self.collectionView.contentOffset.x
            }
        }

        RunLoop.current.add(carousalTimer!, forMode: .common)
    }

Answer 2

// Swift-3

var timr=Timer()
var w:CGFloat=0.0

override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(true)

        configAutoscrollTimer()
    }

    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidAppear(true)

        deconfigAutoscrollTimer()
    }

func configAutoscrollTimer()
    {

        timr=Timer.scheduledTimer(timeInterval: 0.03, target: self, selector: #selector(dashboard_ViewController.autoScrollView), userInfo: nil, repeats: true)
    }
    func deconfigAutoscrollTimer()
    {
        timr.invalidate()

    }
    func onTimer()
    {
        autoScrollView()
    }

    func autoScrollView()
    {

        let initailPoint = CGPoint(x: w,y :0)

        if __CGPointEqualToPoint(initailPoint, ticker.contentOffset)
        {
            if w<collection_view.contentSize.width
            {
                w += 0.5
            }
            else
            {
                w = -self.view.frame.size.width
            }

            let offsetPoint = CGPoint(x: w,y :0)

            collection_view.contentOffset=offsetPoint

        }
        else
        {
            w=collection_view.contentOffset.x
        }
    }

// 这很好用