iOS开发中视图的下拉放大和上拉模糊的效果实现

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

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

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

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)

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

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:

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); 
 
    } 
}