本文實例為大家分享了iOS實現圖片自動切換的具體代碼,供大家參考,具體內容如下
#import "ViewController.h"#define ImageViewCount 5 @interface ViewController ()<UIScrollViewDelegate> @property (weak, nonatomic) IBOutlet UIScrollView *imageScrollView;@property (weak, nonatomic) IBOutlet UIPageControl *imageViewPageControl;@property (strong, nonatomic) NSTimer *timer;@end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; [self addImageView2ScrollView]; self.imageScrollView.contentSize = CGSizeMake(self.imageScrollView.frame.size.width * ImageViewCount, 0); self.imageScrollView.delegate = self; self.imageScrollView.pagingEnabled = YES;//UIScrollView支持拖動分頁 self.imageViewPageControl.numberOfPages = ImageViewCount; [self addScrollTimer];} - (void)rotatePic{ int currentPageIndex = self.imageViewPageControl.currentPage; if(++currentPageIndex == 5){ currentPageIndex = 0; } CGFloat offsetX = currentPageIndex * self.imageScrollView.frame.size.width; [UIView animateWithDuration:1 animations:^{ self.imageScrollView.contentOffset = CGPointMake(offsetX, 0); }];} /**添加圖片到imageScrollView*/- (void)addImageView2ScrollView{ CGFloat imageWidth = self.imageScrollView.frame.size.width; CGFloat imageHeight = self.imageScrollView.frame.size.height; for(int i = 0;i <= ImageViewCount;i++){ UIImageView *imageInScroll = [[UIImageView alloc] init]; imageInScroll.frame = CGRectMake(i * imageWidth, 0, imageWidth, imageHeight); imageInScroll.image = [UIImage imageNamed:[NSString stringWithFormat:@"img_%02d",i + 1]]; [self.imageScrollView addSubview:imageInScroll]; }} // 正滾動時執行- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ CGFloat offX = self.imageScrollView.contentOffset.x;//(0,0)距離content內部左上頂點的x軸長度 NSLog(@"~~~~~~~%f ^^^^^^%f", offX, self.imageScrollView.frame.size.width); int currentPageIndex = (offX + .5f * self.imageScrollView.frame.size.width) / self.imageScrollView.frame.size.width; self.imageViewPageControl.currentPage = currentPageIndex;} - (void)addScrollTimer{ self.timer = [NSTimer timerWithTimeInterval:2 target:self selector:@selector(rotatePic) userInfo:nil repeats:YES]; [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];} - (void)removeScrollTimer{ [self.timer invalidate];//釋放定時器 self.timer = nil;} // 開始準備滾動時執行 移除定時滾動操作- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{ NSLog(@"~~~scrollViewWillBeginDragging"); [self removeScrollTimer];} // 結束滾動后執行 添加定時滾動操作- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ NSLog(@"~~~scrollViewDidEndDragging"); [self addScrollTimer];}@end對UIScrollView的運用,以上代碼中有詳細注釋,需注意2點:
1.注意設置contentSize屬性。其中contentSize表示scroll內容尺寸大小
2.注意設置代理UIScrollViewDelegate,才可調用其中的方法
對于定時器NSTimer的運用需注意
1.在線程的loop中添加定時器
2.注意使用完成回收NSTimer
以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支持武林網。
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