滚动视图及缩放

作者: ThEAll | 来源:发表于2015-12-03 17:45 被阅读269次

import "AppDelegate.h"

import "RootViewController.h"

import "ZoomViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];

RootViewController *rootVC = [[RootViewController alloc]init];
[self.window setRootViewController:rootVC];

ZoomViewController *zoomVC = [[ZoomViewController alloc]init];
[self.window setRootViewController:zoomVC];

return YES;
}

import "RootViewController.h"

@interface RootViewController ()<UIScrollViewDelegate>

@end

@implementation RootViewController

(void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor orangeColor];

// 创建滚动视图当我们显示的内容超过一屏时，就需要用到滚动视图
UIScrollView scroolView = [[UIScrollView alloc]initWithFrame:self.view.frame];
scroolView.tag = 1000;
scroolView.backgroundColor = [UIColor whiteColor];
// 设置滚动区域
[scroolView setContentSize:CGSizeMake(CGRectGetWidth(self.view.frame)3, CGRectGetHeight(self.view.frame))];
// 为scroll添加子视图(设置为4屏)
// NSArray *colorArr = [NSArray arrayWithObjects:[UIColor redColor],[UIColor blueColor],[UIColor whiteColor],[UIColor greenColor], nil];
NSArray *imageArr = [NSArray arrayWithObjects:@"0.png",@"1.png",@"2.png", nil];
for (int i = 0; i < 3; i++) {
```
  UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(CGRectGetWidth(self.view.frame)*i, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame))];
  imageView.image = [UIImage imageNamed:imageArr[i]];
  imageView.userInteractionEnabled = YES;
  [scroolView addSubview:imageView];

  UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(CGRectGetWidth(self.view.frame)*i, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame))];
  label.text = [NSString stringWithFormat:@"这是第%d个视图",i];
  label.backgroundColor = colorArr[i];
  label.textAlignment = NSTextAlignmentCenter;
  label.font = [UIFont systemFontOfSize:60];
  [scroolView addSubview:label];
```
}
[self.view addSubview:scroolView];
// 设置分页效果(默认值为NO)
scroolView.pagingEnabled = YES;
// 设置横向滚动条是否显示（默认值为YES）
scroolView.showsHorizontalScrollIndicator = YES;

// 设置边界是否有反弹效果(默认值为YES)
scroolView.bounces = NO;
// 设置代理
scroolView.delegate = self;

// 初始化UIPageControl
UIPageControl *pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(0, CGRectGetHeight(self.view.frame)-40, CGRectGetWidth(self.view.frame), 40)];
pageControl.tag = 1001;

pageControl.pageIndicatorTintColor = [UIColor blackColor];
pageControl.currentPageIndicatorTintColor = [UIColor yellowColor];
// 设置页数
[pageControl setNumberOfPages:3];
// 设置当前所在页
pageControl.currentPage = 1;
// 添加触发事件
[pageControl addTarget:self action:@selector(pageAction:) forControlEvents:UIControlEventValueChanged];
[pageControl setBackgroundColor:[UIColor grayColor]];
[self.view addSubview:pageControl];

}

//pageControl的回调方法
-(void)pageAction:(UIPageControl)sender{
// 根据当前的页数，使得scrollView也滑动到对应的子视图通过设置scrollView的contentOffset来实现（改变contentOffset实际上就是改变scrollView的bounds）
// 得到当前的页数
int page = (int)sender.currentPage;
// 根据当前页数来计算偏移量
// 得到scrollView
UIScrollView scrollView = (UIScrollView)[self.view viewWithTag:1000];
// 设置scrollView的偏移量当前的页数乘以屏幕宽度
[scrollView setContentOffset:CGPointMake(pageCGRectGetWidth(self.view.frame), 0) animated:YES];
}

pragma mark --- 滚动视图的代理方法

// 开始拖拽（手指触碰到屏幕，并且移动）
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
NSLog(@"-------%s",func);
}

// 已经开始滚动（只要scrollView是滚动状态就会调用次方法）
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
// 滚动视图上面的子视图可以移动，不是子视图改变自身的frame值，而是通过更改滚动视图（也就是子视图的父视图）的bounds的origin（也就是x,y）来更改子视图在父视图（滚动视图）上显示的位置
// scrollView的偏移量
CGPoint offSet = scrollView.contentOffset;
NSLog(@"_____%f",offSet.x);
// 得到scrollView的bounds的x点
float x = scrollView.bounds.origin.x;
NSLog(@"bounds********%f",x);
NSLog(@"--------%s",func);
}

// 停止拖拽当手指（触摸对象）离开，正在滚动的视图减速
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
NSLog(@"_____%s",func);
}

// 视图真正静止（视图不动了）
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
// 根据scrollView的偏移量来计算当前的页数
int page = (int)scrollView.contentOffset.x/CGRectGetWidth(self.view.frame);
// 得到pageControl
UIPageControl pageControl = (UIPageControl)[self.view viewWithTag:1001];
// 设置当前的页数
pageControl.currentPage = page;

NSLog(@"%s",__func__);

}

(void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

/*

pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/

@end

import "ZoomViewController.h"

@interface ZoomViewController ()<UIScrollViewDelegate>

@end

@implementation ZoomViewController

(void)viewDidLoad {
[super viewDidLoad];

// 初始化scrollView
UIScrollView *scrollView = [[UIScrollView alloc]initWithFrame:self.view.frame];
[scrollView setBackgroundColor:[UIColor orangeColor]];
// 设置scrollView代理
scrollView.delegate = self;
// 设置缩放比例
// 设置可缩小到的最小比例
scrollView.minimumZoomScale = 0.5;
// 设置可放大到的最大比例
scrollView.maximumZoomScale = 2.0;

[self.view addSubview:scrollView];
// 添加图片，使得添加的图片宽高成比例
UIImage myImage = [UIImage imageNamed:@"3.png"];
// 得到图片的原始宽高
float imageWidth = myImage.size.width;
float imageHeight = myImage.size.height;
// 这里规定imageView的宽为200，根据此宽度，得到等比例的高度
float imageViewWidth = 200;
float imageViewHeight = 200(imageHeight/imageWidth);
// 初始化UIImageView
UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, imageViewWidth, imageViewHeight)];
imageView.tag = 1000;
// 为imageView设置图片
imageView.image = myImage;
// 让imageView居中
imageView.center = self.view.center;
[scrollView addSubview:imageView];

}

pragma mark --- 滚动视图与缩放有关的代理方法

// 指定scrollView的某一个子视图为可缩放视图，前提条件是此视图已经添加到scrollView上面
-(UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView{
UIImageView imageView = (UIImageView)[scrollView viewWithTag:1000];
return imageView;
}

// 开始缩放第二个参数view：是指我们将要缩放的视图（这里就是imageView）
-(void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view{
NSLog(@"%@",view);
}

// 正在缩放只要正在缩放就会执行此方法，所以此方法在放缩过程中会多次调用
-(void)scrollViewDidZoom:(UIScrollView *)scrollView{

//  在缩放过程中，为了使得该子视图一直在屏幕中间位置，所以我们需要在它缩放过程中一直调整他的center
//  得到scrollView的子视图
UIImageView *imageView = (UIImageView*)[scrollView viewWithTag:1000];
//  打印imageView的frame。分析为什么它的位置会改变
NSLog(@"frame___%@",NSStringFromCGRect(imageView.frame));

//  设置imageView的center，使得它的位置一直在屏幕中间
imageView.center =self.view.center;

//  打印contentSize  分析为什么缩放之后会滑动
NSLog(@"contentSize------%@",NSStringFromCGSize(scrollView.contentSize));

}

// 缩放结束
// 第二个参数：当前正在缩放的视图
// 第三个参数：当前正在缩放视图的缩放比例
-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale{
// 缩放完成之后恢复原大小，这里使用的是2D方式变换函数中与捏合有关的函数
// view.transform = CGAffineTransformMakeScale(1, 1);
}

(void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

/*

pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@end

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滚动视图及缩放

import "AppDelegate.h"

import "RootViewController.h"

import "ZoomViewController.h"

import "RootViewController.h"

pragma mark --- 滚动视图的代理方法

pragma mark - Navigation

@end

import "ZoomViewController.h"

pragma mark --- 滚动视图与缩放有关的代理方法

pragma mark - Navigation

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