iOS开篇——UI之UIScrollView

//创建一个全屏大小的scrollerView
    UIScrollView * scrollerView = [[UIScrollView alloc]initWithFrame:self.view.bounds] ;
    //添加到self.view上
    [self.view addSubview:scrollerView];
    
    //创建一个图片
    UIImage * image1 = [UIImage imageNamed:@"1"];
    
    //设置scrollerView的移动范围 ********
    //如果不设置 默认是scrollerView的本身大小移动范围
    //如果子视图大小没超过scrollerView的自身大小 则不会移动
    scrollerView.contentSize = CGSizeMake(image1.size.width, image1.size.height);
    
    //设置子视图的偏移量 **********
//    [scrollerView setContentOffset:CGPointMake(200, 200)animated:YES];
    //不带动画
//    scrollerView.contentOffset = CGPointMake(200, 200) ;
    
    //设置scrollerView子视图距离它本身的位置
//    scrollerView.contentInset = UIEdgeInsetsMake(10, 10, 30, 30) ;
    //是否反弹 默认YES可以超出边界   设置为NO不可超出边界 且不可反弹
    scrollerView.bounces = YES;
    
    //设置垂直和水平 滚动条是否出现
    scrollerView.showsHorizontalScrollIndicator = YES;
    scrollerView.showsVerticalScrollIndicator = YES;
    
    //设置缩放比例大小
    scrollerView.minimumZoomScale = 0.5;
    scrollerView.maximumZoomScale = 2;
    
    //设置滚动条与scrollerView边界的最小距离
    scrollerView.scrollIndicatorInsets = UIEdgeInsetsMake(10, 10, 10, 10);
    //设置滚动条样式
    scrollerView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
    /*
     typedef NS_ENUM(NSInteger, UIScrollViewIndicatorStyle) {
     UIScrollViewIndicatorStyleDefault,     // black with white border. good against any background
     UIScrollViewIndicatorStyleBlack,       // black only. smaller. good against a white background
     UIScrollViewIndicatorStyleWhite        // white only. smaller. good against a black background
     };
     */
    
    //设置代理
    scrollerView.delegate = self;
    
    //往scrollerView上添加图片
    [scrollerView addSubview: [[UIImageView alloc]initWithImage:image1]];
    
    //设置拖动惯性 数字越大 停下来越慢
    scrollerView.decelerationRate = 1;

UIScrollViewDelegate 代理方法

#pragma mark - delegate方法

//scrollView正在滚动
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
//    NSLog(@"正在滚动");
}

//将要开始手指拖动
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    NSLog(@"将要开始拖动");
}

//将要停止手指拖动
//第一个参数为它本身   第二个参数为加速度(惯性)  第三个参数为要停到的位置 停止拖动时已经计算好
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
    
    NSLog(@"将要停止拖动");
    
}
//已经结束手指拖动
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    NSLog(@"已经停止拖动");
}


//将要开始惯性滑动
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    NSLog(@"将要开始惯性滑动");
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    NSLog(@"已经结束惯性滑动");
    
    //设置偏移量为(0,0)点
//    [scrollView setContentOffset:CGPointZero animated:YES];
}

//已经结束位移动画
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{
    NSLog(@"已经结束位移动画");
}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
    NSLog(@"发生了缩放");
    
}
- (nullable UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
    //返回值为要缩放的视图
    return scrollView.subviews[0];
}
    //将要开始缩放
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view {

    NSLog(@"将要开始缩放");
}
//已经结束缩放
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view atScale:(CGFloat)scale{
    NSLog(@"已经结束缩放");
}

//能否按顶部返回顶端
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{
    return YES;
}
//已经跳到顶端
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{
    NSLog(@"已经回到顶端");
}