UIPageControl, UIScrollView属性及UIScrollViewDelegate详解

UIPageControl, UIScrollView属性

#import "RootView.h"@implementation RootView- (instancetype)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        [self createSubviews];    }    return self;}- (void)createSubviews{    self.backgroundColor = [UIColor blackColor];    // UIPageControl    UIPageControl *pageC = [[UIPageControl alloc] initWithFrame:CGRectMake(50, 500, 200, 30)];    pageC.backgroundColor = [UIColor orangeColor];    // 需要设置个数才会生效    pageC.numberOfPages = 10;    // 赋值时 - 默认初始位置    // 读取时 - 当前所在位置    pageC.currentPage = 5;    // 未选中时点的颜色    pageC.pageIndicatorTintColor = [UIColor redColor];    // 选中时点的颜色    pageC.currentPageIndicatorTintColor = [UIColor blueColor];    [pageC addTarget:self action:@selector(pageAction:) forControlEvents:UIControlEventValueChanged];    [self addSubview:pageC];    [pageC release];    // 2, UIScrollView - 重点!!!!!!!!    UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:self.frame];#pragma 重要, 核心属性    // 横向设置19的图片位    scroll.contentSize = CGSizeMake(self.frame.size.width * 19, 0);    // 使能按页翻动    scroll.pagingEnabled = YES;//    // 关闭边缘反弹//    scroll.bounces = NO;#pragma 重要, 实用属性    // 偏移 - 当前显示的图片槽    scroll.contentOffset = CGPointMake(self.frame.size.width * 3, 0);    // 使能调到最顶端的功能    scroll.scrollsToTop = YES;    // 是否允许滑动(默认允许)    scroll.scrollEnabled = NO;    // 水平/垂直跟随条    scroll.showsHorizontalScrollIndicator = NO;    scroll.showsVerticalScrollIndicator = NO;    /****************************** 缩放部分**************************/    // 最小/最大缩放倍数    scroll.minimumZoomScale = 0.5;    scroll.maximumZoomScale = 10;    // 注意! 要实现缩放功能需要签订协议    scroll.delegate = self;    /********************************************************************/    [self addSubview:scroll];    [scroll release];    for (NSInteger i = 0; i < 19; i++) {        // 注意: 1. 先看图片序号的命名格式1 or 01; 2. 再看图片的起始序号0 or 1        NSString *fileName = [NSString stringWithFormat:@"image%ld", i + 1];        NSString *filePath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"jpg"];        UIImage *image = [UIImage imageNamed:filePath];        // 注意: imageV的x坐标        UIImageView *imageV = [[UIImageView alloc] initWithFrame:CGRectMake(self.frame.size.width * i, 0, self.frame.size.width, self.frame.size.height)];        imageV.image = image;        // for循环的最终目的 - 创建19个imageView, 分别添加到scroll的槽里        [scroll addSubview:imageV];    }    pageC = [[UIPageControl alloc] initWithFrame:CGRectMake(50, 600, self.frame.size.width - 50 * 2, 30)];    pageC.numberOfPages = 19;    // 注意, page的起点与scroll的初始偏移量一样    pageC.currentPage = scroll.contentOffset.x / self.frame.size.width;    [pageC addTarget:self action:@selector(pageAction:) forControlEvents:UIControlEventValueChanged];    [self addSubview:pageC];    [pageC release];}#pragma 重要, 一般结束状态的处理可在此方法中进行- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{    NSLog(@"结束减速时触发");    NSLog(@"%f", scrollView.contentOffset.x);}/***************************** 缩放相关方法 ***************************/// 允许哪个页面缩放- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{    return [scrollView.subviews objectAtIndex:0];}- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale{    [[scrollView.subviews objectAtIndex:0] setCenter:CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2)];}- (void)scrollViewDidZoom:(UIScrollView *)scrollView{    NSLog(@"缩放操作时触发");    // 将缩放时图片的中心点设置为屏幕的中心点    [[scrollView.subviews objectAtIndex:0] setCenter:self.center];}/********************************************************************/- (void)pageAction:(UIPageControl *)sender{}

UIScrollView中添加可用于缩放的subScrollView

#import "RootView.h"@implementation RootView- (void)dealloc{    [_scrollV release];    [super dealloc];}- (instancetype)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        [self createSubvuews];    }    return self;}- (void)createSubvuews{    self.scrollV = [[UIScrollView alloc] initWithFrame:self.frame];    self.scrollV.contentSize = CGSizeMake(self.frame.size.width *19, 0);    for (NSInteger i = 0; i < 19; i++) {        // 创建subScrollV 为了缩放        UIScrollView *subScrollV = [[UIScrollView alloc] initWithFrame:CGRectMake(self.frame.size.width * i, 0, self.frame.size.width, self.frame.size.height)];        subScrollV.minimumZoomScale = 0.5;        subScrollV.maximumZoomScale = 5;        // 缩放比例//        subScrollV.zoomScale = 1.0;        subScrollV.delegate = self;        [self.scrollV addSubview:subScrollV];        [subScrollV release];        NSString *fileName = [NSString stringWithFormat:@"image%ld", i + 1];        NSString *filePath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"jpg"];        UIImageView *imageV = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];        imageV.image = [UIImage imageWithContentsOfFile:filePath];        [subScrollV addSubview:imageV];        [imageV release];    }    // scrollV负责移动拖拽, subScrollV负责缩放    self.scrollV.delegate = self;    self.scrollV.pagingEnabled = YES;    [self addSubview:self.scrollV];    [_scrollV release];}#pragma 触摸的过程 - 开始拖拽(手指触摸) -> 结束拖拽(松开手指)-> 减速开始(回弹的过程) -> 减速结束(图片最终稳定下来)- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{    self.preIndex = scrollView.contentOffset.x / self.frame.size.width;}- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{    NSInteger curIndex = self.scrollV.contentOffset.x / self.frame.size.width;    if (self.preIndex != curIndex) {        [[self.scrollV.subviews objectAtIndex:self.preIndex] setZoomScale:1.0];    }    //    [[scrollView.subviews objectAtIndex:self.preIndex] setZoomScale:1.0];    //    NSLog(@"所在页码%f", scrollView.contentOffset.x / self.frame.size.width);}- (void)scrollViewDidZoom:(UIScrollView *)scrollView{    // 保证缩放在中心位置    [scrollView.subviews.firstObject setCenter:self.center];}// 允许哪个视图缩放- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{    // 当前的scrollView是subScrollView    return scrollView.subviews.firstObject;}@end

UIScrollViewDelegate中的各种方法

//scrollView滚动时，就调用该方法。任何offset值改变都调用该方法。即滚动过程中，调用多次 - (void)scrollViewDidScroll:(UIScrollView *)scrollView{    NSLog(@"scrollViewDidScroll");    CGPoint point=scrollView.contentOffset;    NSLog(@"%f,%f",point.x,point.y);    // 从中可以读取contentOffset属性以确定其滚动到的位置。    // 注意：当ContentSize属性小于Frame时，将不会出发滚动}

// 当scrollView缩放时，调用该方法。在缩放过程中，回多次调用- (void)scrollViewDidZoom:(UIScrollView *)scrollView{    NSLog(@"scrollViewDidScroll");    float value=scrollView.zoomScale;    NSLog(@"%f",value);}

// 当开始滚动视图时，执行该方法。一次有效滑动（开始滑动，滑动一小段距离，只要手指不松开，只算一次滑动），只执行一次。- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{    NSLog(@"scrollViewWillBeginDragging");}

// 滑动scrollView，并且手指离开时执行。一次有效滑动，只执行一次。// 当pagingEnabled属性为YES时，不调用，该方法- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{    NSLog(@"scrollViewWillEndDragging");}

// 滑动视图，当手指离开屏幕那一霎那，调用该方法。一次有效滑动，只执行一次。// decelerate,指代，当我们手指离开那一瞬后，视图是否还将继续向前滚动（一段距离），经过测试，decelerate=YES- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{    NSLog(@"scrollViewDidEndDragging");    if (decelerate) {        NSLog(@"decelerate");    }else{         NSLog(@"no decelerate");    }    CGPoint point=scrollView.contentOffset;    NSLog(@"%f,%f",point.x,point.y);}

// 滑动减速时调用该方法。- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{    NSLog(@"scrollViewWillBeginDecelerating");    // 该方法在scrollViewDidEndDragging方法之后。}

// 滚动视图减速完成，滚动将停止时，调用该方法。一次有效滑动，只执行一次。- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{    NSLog(@"scrollViewDidEndDecelerating");    [_scrollView setContentOffset:CGPointMake(0, 500) animated:YES];}

// 当滚动视图动画完成后，调用该方法，如果没有动画，那么该方法将不被调用- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{    NSLog(@"scrollViewDidEndScrollingAnimation");    // 有效的动画方法为：    //    - (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated 方法    //    - (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated 方法}

// 返回将要缩放的UIView对象。要执行多次- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{    NSLog(@"viewForZoomingInScrollView");    return  self.imgView;}

// 当将要开始缩放时，执行该方法。一次有效缩放，就只执行一次。- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view{    NSLog(@"scrollViewWillBeginZooming");}

// 当缩放结束后，并且缩放大小回到minimumZoomScale与maximumZoomScale之间后（我们也许会超出缩放范围），调用该方法。- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale{    NSLog(@"scrollViewDidEndZooming");}

// 指示当用户点击状态栏后，滚动视图是否能够滚动到顶部。需要设置滚动视图的属性：_scrollView.scrollsToTop=YES;- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{    return YES;}

// 当滚动视图滚动到最顶端后，执行该方法- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{    NSLog(@"scrollViewDidScrollToTop");}

判断uiscrollview是向上滚动还是向下滚动

int _lastPosition;    //A variable define in headfile  - (void)scrollViewDidScroll:(UIScrollView *)scrollView{      int currentPostion = scrollView.contentOffset.y;      if (currentPostion - _lastPosition > 25) {          _lastPosition = currentPostion;          NSLog(@"ScrollUp now");      }      else if (_lastPosition - currentPostion > 25)      {          _lastPosition = currentPostion;          NSLog(@"ScrollDown now");      }  }// 25 可以是任意数字，可根据自己的需要来设定。

// 升级版：到达顶部或底部时不会反弹- (void)scrollViewDidScroll:(UIScrollView *)scrollView{    int currentPostion = scrollView.contentOffset.y;    if (currentPostion - _lastPosition > 20  && currentPostion > 0) {        //这个地方加上 currentPostion > 0 即可）        _lastPosition = currentPostion;        NSLog(@"ScrollUp now");    }    else if ((_lastPosition - currentPostion > 20) && (currentPostion  <= scrollView.contentSize.height-scrollView.bounds.size.height-20) ){        _lastPosition = currentPostion;        NSLog(@"ScrollDown now");    }}