iOS开发中视图的下拉放大和上拉模糊的效果实现

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我是靠谱客的博主呆萌流沙，最近开发中收集的这篇文章主要介绍iOS开发中视图的下拉放大和上拉模糊的效果实现，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

把"秘密"的Cell效果整体视图都放到scrollView中,基本是和secret app 一模一样的效果了.
代码如下:(模糊效果的类就不写了,大家可以搜"UIImage+ImageEffects",还要导入Accelerate.framework)
1.MTSecretAppEffect.h

复制代码代码如下:

#import <Foundation/Foundation.h>

@interface MTSecretAppEffect : NSObject

/**
* 创建整体的scrollView,把headScrollView和tableView全部加载在上面,靠它来上下滑动,其余的滑动全部禁止
*
* @return mainScrollView
*/
- (UIScrollView *)createMainScrollView;

/**
* 创建headScrollView
*
* @return headScrollView
*/
- (UIScrollView *)createHeadScrollView;

/**
* 创建头部的模糊view
*
* @param scrollview headScrollView
*
* @return blurImageView
*/
- (UIImageView *)createBlurImageViewOfView:(UIScrollView *)scrollview;

/**
* 在- (void)scrollViewDidScroll:(UIScrollView *)scrollView 中调用的方法
*
* @param scrollView
* @param mainScrollView
* @param tableView
* @param headScrollView
* @param blurImageView
*/
- (void)scrollDidScrollView:(UIScrollView *)scrollView withMainScrollView:(UIScrollView *)mainScrollView withTableView:(UITableView *)tableView withHeadScrollView:(UIScrollView *)headScrollView withBlurImageView:(UIImageView *)blurImageView;
@end

2.MTSecretAppEffect.m

复制代码代码如下:

#import "MTSecretAppEffect.h"
#import "UIImage+ImageEffects.h"
#import <QuartzCore/QuartzCore.h>

#define HEADER_HEIGHT 200.0f
#define HEADER_INIT_FRAME CGRectMake(0, 0, 320, HEADER_HEIGHT)

const CGFloat kBarHeight = 50.0f;
const CGFloat kBackgroundParallexFactor = 0.5f;
const CGFloat kBlurFadeInFactor = 0.015f;

@implementation MTSecretAppEffect

// 欠缺:调用者设置代理
- (UIScrollView *)createMainScrollView{

    // 和Self.view同大小的底部ScrollView
    UIScrollView *mainScrollView = [[UIScrollView alloc] initWithFrame:[UIApplication sharedApplication].keyWindow.frame];
    mainScrollView.bounces = YES;
    mainScrollView.alwaysBounceVertical = YES;
    mainScrollView.contentSize = CGSizeZero;
    mainScrollView.showsVerticalScrollIndicator = YES;
    mainScrollView.scrollIndicatorInsets = UIEdgeInsetsMake(50.0f, 0, 0, 0);

    return mainScrollView;

}

- (UIScrollView *)createHeadScrollView{

    UIScrollView *headScrollView = [[UIScrollView alloc] initWithFrame:HEADER_INIT_FRAME];
    headScrollView.scrollEnabled = NO;
    headScrollView.contentSize = CGSizeMake(320, 1000);

    return headScrollView;
}

- (UIImageView *)createBlurImageViewOfView:(UIScrollView *)scrollview{

    UIGraphicsBeginImageContextWithOptions(scrollview.bounds.size, scrollview.opaque, 0.0);
    [scrollview.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageView *blurImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, HEADER_HEIGHT)];
    blurImageView.image = [img applyBlurWithRadius:12 tintColor:[UIColor colorWithWhite:0.8 alpha:0.4] saturationDeltaFactor:1.8 maskImage:nil];
    blurImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    blurImageView.alpha = 0;
    blurImageView.backgroundColor = [UIColor clearColor];

    return blurImageView;
}

- (void)scrollDidScrollView:(UIScrollView *)scrollView withMainScrollView:(UIScrollView *)mainScrollView withTableView:(UITableView *)tableView withHeadScrollView:(UIScrollView *)headScrollView withBlurImageView:(UIImageView *)blurImageView{

    CGFloat y = 0.0f;
    CGRect rect = HEADER_INIT_FRAME;
    if (scrollView.contentOffset.y < 0.0f) {
        // 下拉变大效果
        y = fabs(MIN(0.0f, mainScrollView.contentOffset.y));
        headScrollView.frame = CGRectMake(CGRectGetMinX(rect) - y / 2.0f, CGRectGetMinY(rect) - y, CGRectGetWidth(rect) + y, CGRectGetHeight(rect) + y);

    }
    else {

        y = mainScrollView.contentOffset.y;
        blurImageView.alpha = MIN(1 , y * kBlurFadeInFactor);
        CGFloat backgroundScrollViewLimit = headScrollView.frame.size.height - kBarHeight;

        if (y > backgroundScrollViewLimit) {
            headScrollView.frame = (CGRect) {.origin = {0, y - headScrollView.frame.size.height + kBarHeight}, .size = {320, HEADER_HEIGHT}};
            tableView.frame = (CGRect){.origin = {0, CGRectGetMinY(headScrollView.frame) + CGRectGetHeight(headScrollView.frame)}, .size = tableView.frame.size };
            tableView.contentOffset = CGPointMake (0, y - backgroundScrollViewLimit);
            CGFloat contentOffsetY = -backgroundScrollViewLimit * kBackgroundParallexFactor;
            [headScrollView setContentOffset:(CGPoint){0,contentOffsetY} animated:NO];
        }
        else {
            headScrollView.frame = rect;
            tableView.frame = (CGRect){.origin = {0, CGRectGetMinY(rect) + CGRectGetHeight(rect)}, .size = tableView.frame.size };
            [tableView setContentOffset:(CGPoint){0,0} animated:NO];
            [headScrollView setContentOffset:CGPointMake(0, -y * kBackgroundParallexFactor)animated:NO];
        }
    }

}

@end

3.main.m

复制代码代码如下:

#import "RootViewController.h"  

#import "CommentCell.h"  

#import "MTSecretAppEffect.h"  

#define HEADER_HEIGHT 200.0f  

@interface RootViewController () <UIScrollViewDelegate, UITableViewDataSource, UITableViewDelegate>  

@property (nonatomic,strong) MTSecretAppEffect *secretEffect;     // secretApp 效果对象  

@property (nonatomic,strong) UIScrollView *mainScrollView;        // 与view相同大小的scrollView  

@property (nonatomic,strong) UIScrollView *headScrollView;        //  

@property (nonatomic,strong) UIImageView  *blurImageView;         //  

@property (nonatomic,strong) UITableView *tableView;              //  

@end  

@implementation RootViewController  

- (void)viewDidLoad  

{  

    [super viewDidLoad];  

    // 0.创建SecretApp effect 效果对象  

    self.secretEffect = [[MTSecretAppEffect alloc] init];  

    // 1.主底部scrollView  

    self.mainScrollView = [self.secretEffect createMainScrollView];  

    self.mainScrollView.delegate = self;  

    self.view = self.mainScrollView;  

    // 2.head背景View  

    self.headScrollView = [self.secretEffect createHeadScrollView];  

    // 3.背景图片视图  

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, HEADER_HEIGHT)];  

    imageView.image = [UIImage imageNamed:@"secret.png"];  

    imageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;  

    [self.headScrollView  addSubview:imageView];  

    // 4.模糊视图  

    _blurImageView = [self.secretEffect createBlurImageViewOfView:self.headScrollView];  

    [self.headScrollView addSubview:_blurImageView];  

    // 5.tableView  

    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, HEADER_HEIGHT, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame) - 50 ) style:UITableViewStylePlain];  

    self.tableView.scrollEnabled = NO;  

    self.tableView.delegate = self;  

    self.tableView.dataSource = self;  

    self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];  

    self.tableView.separatorColor = [UIColor clearColor];  

    // 6.添加视图  

    [self.view addSubview:self.headScrollView];  

    [self.view addSubview:self.tableView];  

    // 7.设置一下  

    self.mainScrollView.contentSize = CGSizeMake(320, self.tableView.contentSize.height + CGRectGetHeight(self.headScrollView.frame));  

}  

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {  

    // 8.调用方法  

    [self.secretEffect scrollDidScrollView:scrollView withMainScrollView:self.mainScrollView withTableView:self.tableView withHeadScrollView:self.headScrollView withBlurImageView:self.blurImageView];  

}  

#pragma mark - 隐藏状态栏  

- (BOOL)prefersStatusBarHidden {  

    return YES;  

}  

#pragma mark - UITableView dataSource  

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {  

    return 1;  

}  

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {  

    return 20;  

}  

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {  

    return 40;  

}  

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {  

    CommentCell *cell = [tableView dequeueReusableCellWithIdentifier:[NSString stringWithFormat:@"Cell %ld", indexPath.row]];  

    if (!cell) {  

        cell = [[CommentCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:[NSString stringWithFormat:@"Cell %ld", indexPath.row]];  

    }  

    cell.textLabel.text = [NSString stringWithFormat:@"section = %ld row = %ld",indexPath.section,indexPath.row];  

    return cell;  

}  

- (void)didReceiveMemoryWarning  

{  

    [super didReceiveMemoryWarning];  

    // Dispose of any resources that can be recreated.  

}  

@end

效果图:
PPPPPPPPPPPPPPPPPPPPPP1
它主要效果:下拉头部视图放大,上拉视图模糊而且到一定位置固定不动,其他Cell可以继续上移.
封装的主要效果类:MTHeadEffect.m(.h文件省略,很简单的)

复制代码代码如下:

#import "MTHeadEffect.h"
#import <QuartzCore/QuartzCore.h>
#import <Accelerate/Accelerate.h>

// 屏幕的物理宽度
#define ScreenWidth [UIScreen mainScreen].bounds.size.width
#define HeadViewH 40

CGFloat const kImageOriginHight = 200.f;

@implementation MTHeadEffect

+ (void)viewDidScroll:(UIScrollView *)tableView withHeadView:(UIImageView *)headView withBlur:(CGFloat)blur{

    NSLog(@"y = %f",tableView.contentOffset.y);
    if (tableView.contentOffset.y > kImageOriginHight - HeadViewH) {

        headView.frame = CGRectMake(0, -(kImageOriginHight - HeadViewH), ScreenWidth, kImageOriginHight);
        [[UIApplication sharedApplication].keyWindow addSubview:headView];

    }else if ((tableView.contentOffset.y < kImageOriginHight - HeadViewH) && tableView.contentOffset.y > 0){

        blur = (tableView.contentOffset.y) / 500.0 + 0.45;
        headView.image = [[UIImage imageNamed:@"2"] boxblurImageWithBlur:blur];
        headView.frame = CGRectMake(0, 0, ScreenWidth, kImageOriginHight);
        [tableView addSubview:headView];

    }else if (tableView.contentOffset.y <= 0){

        // 放大效果---x,y坐标的增量和宽度,高度的增量保持一致
        CGFloat offset = -tableView.contentOffset.y;
        headView.frame = CGRectMake(-offset,-offset, ScreenWidth+ offset * 2, kImageOriginHight + offset);
        headView.image = [[UIImage imageNamed:@"2"] boxblurImageWithBlur:0.01];
    }

}

@end

@implementation UIImage (BlurEffect)

// 为高斯模糊效果封装的一个类目
-(UIImage *)boxblurImageWithBlur:(CGFloat)blur {

    NSData *imageData = UIImageJPEGRepresentation(self, 1); // convert to jpeg
    UIImage* destImage = [UIImage imageWithData:imageData];


    if (blur < 0.f || blur > 1.f) {
        blur = 0.5f;
    }
    int boxSize = (int)(blur * 40);
    boxSize = boxSize - (boxSize % 2) + 1;

    CGImageRef img = destImage.CGImage;

    vImage_Buffer inBuffer, outBuffer;

    vImage_Error error;

    voidvoid *pixelBuffer;


    //create vImage_Buffer with data from CGImageRef

    CGDataProviderRef inProvider = CGImageGetDataProvider(img);
    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);


    inBuffer.width = CGImageGetWidth(img);
    inBuffer.height = CGImageGetHeight(img);
    inBuffer.rowBytes = CGImageGetBytesPerRow(img);

    inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);

    //create vImage_Buffer for output

    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

    if(pixelBuffer == NULL)
        NSLog(@"No pixelbuffer");

    outBuffer.data = pixelBuffer;
    outBuffer.width = CGImageGetWidth(img);
    outBuffer.height = CGImageGetHeight(img);
    outBuffer.rowBytes = CGImageGetBytesPerRow(img);

    // Create a third buffer for intermediate processing
    voidvoid *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
    vImage_Buffer outBuffer2;
    outBuffer2.data = pixelBuffer2;
    outBuffer2.width = CGImageGetWidth(img);
    outBuffer2.height = CGImageGetHeight(img);
    outBuffer2.rowBytes = CGImageGetBytesPerRow(img);

    //perform convolution
    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    if (error) {
        NSLog(@"error from convolution %ld", error);
    }
    error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    if (error) {
        NSLog(@"error from convolution %ld", error);
    }
    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    if (error) {
        NSLog(@"error from convolution %ld", error);
    }

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef ctx = CGBitmapContextCreate(outBuffer.data,
                                             outBuffer.width,
                                             outBuffer.height,
                                             8,
                                             outBuffer.rowBytes,
                                             colorSpace,
                                             (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

    //clean up
    CGContextRelease(ctx);
    CGColorSpaceRelease(colorSpace);

    free(pixelBuffer);
    free(pixelBuffer2);
    CFRelease(inBitmapData);

    CGImageRelease(imageRef);

    return returnImage;
}

@end

@main.m

复制代码代码如下:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    // tableView
    self.testTableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, 320, 568) style:UITableViewStylePlain];
    self.testTableView.delegate = self;
    self.testTableView.dataSource = self;
    [self.view addSubview:_testTableView];

    /**
     * 隐藏状态栏效果
     * 1.系统提供了2种动画,一种是偏移,一种是渐隐
     * 2.在plist文件中将”View controller-based status bar appearance” 设置为 “No”
     */
    [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];

    // headView不作为tableHeadView,而是覆盖在第一个Cell上
    self.headView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 200)];
    self.headView.image = [[UIImage imageNamed:@"2"] boxblurImageWithBlur:0.01];
    self.headView.contentMode = UIViewContentModeScaleAspectFill; // 图片展示全高度
    self.headView.clipsToBounds = YES;
    [self.testTableView addSubview:self.headView];

}

#pragma mark - scroll delegate 头部视图效果方法
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{

    [MTHeadEffect viewDidScroll:scrollView withHeadView:self.headView withBlur:0.01];
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{

    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{

    return 25;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{

    if (indexPath.row == 0) {
        return 200;
    }
    return 40;

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

    static NSString *cellIdentf = @"cell";
    UITableViewCell *cell = [tableView dequeueReusableHeaderFooterViewWithIdentifier:cellIdentf];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentf];
    }
    cell.textLabel.text = [NSString stringWithFormat:@"section = %ld row = %ld",indexPath.section,indexPath.row];
    return cell;

}

效果图:额,不会制作gif动图,所以不太好演示,反正关键代码已经给出,大家可以自己去尝试.
第三方FXBlurView做法的关键代码:

复制代码代码如下:

- (void)createBlurView{

    self.blurView = [[FXBlurView alloc] initWithFrame:CGRectMake(0, 0, ScreenWidth, kOriginHight)];
    self.blurView.tintColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:1];
    self.blurView.blurRadius = 1.0;
    self.blurView.dynamic = YES;
    self.blurView.alpha = 0.0;
    self.blurView.contentMode = UIViewContentModeBottom;

}

#pragma mark - scroll delegate 头部视图效果方法
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{

    if (scrollView.contentOffset.y > 0) {

        self.blurView.alpha = 1.0;
        self.blurView.blurRadius = scrollView.contentOffset.y / 4.0;
    }
    if (scrollView.contentOffset.y == 0) {
        self.blurView.alpha = 0.0;
    }
    if (scrollView.contentOffset.y < 0) {

        CGFloat offset = - scrollView.contentOffset.y;
        self.blurView.alpha = 0.0;
        NSArray *indexPathArray = [self.testTableView indexPathsForVisibleRows];
        HMTBlurTableViewCell *blurCell = (HMTBlurTableViewCell *)[self.testTableView cellForRowAtIndexPath:[indexPathArray objectAtIndex:0]];
        blurCell.blurImageView.frame = CGRectMake(-offset, -offset, ScreenWidth + offset * 2, kOriginHight + offset);

    }
}