////  ViewController.m//  CDTableViewHeaderDemo////  Created by Alex on 15/8/21.//  Copyright (c) 2015年 Alex. All rights reserved.//#define KScreen_Width [UIScreen mainScreen].bounds.size.width#define KScreen_Height [UIScreen mainScreen].bounds.size.height#import "ViewController.h"const CGFloat BackGroupHeight = 200;const CGFloat HeadImageHeight= 80;@interface ViewController ()
     
      {        UITableView *demoTableView;        UIImageView *imageBG;    UIView *BGView;        UIImageView *headImageView;    UILabel *nameLabel;    UILabel *titleLabel;        UIButton *leftBtn;    UIButton *rightBtn;}@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    self.automaticallyAdjustsScrollViewInsets=NO;    [self.navigationController.navigationBar setShadowImage:[[UIImage alloc] init]];               [self setupUI];}-(void)setupUI{    demoTableView=[[UITableView alloc]init];    demoTableView.delegate=self;    demoTableView.dataSource=self;    [demoTableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];    demoTableView.frame=[UIScreen mainScreen].bounds;    demoTableView.contentInset=UIEdgeInsetsMake(BackGroupHeight, 0, 0, 0);        [self.view addSubview:demoTableView];        //    imageBG=[[UIImageView alloc]init];    imageBG.frame=CGRectMake(0, -BackGroupHeight, KScreen_Width, BackGroupHeight);    imageBG.image=[UIImage imageNamed:@"BGimage.jpg"];        [demoTableView addSubview:imageBG];//    demoTableView.tableHeaderView = imageBG;    //    BGView=[[UIView alloc]init];    BGView.backgroundColor=[UIColor clearColor];    BGView.frame=CGRectMake(0, -BackGroupHeight, KScreen_Width, BackGroupHeight);        [demoTableView addSubview:BGView];        //    headImageView=[[UIImageView alloc]init];    headImageView.image=[UIImage imageNamed:@"myheadimage.jpg"];    headImageView.frame=CGRectMake((KScreen_Width-HeadImageHeight)/2, 50, HeadImageHeight, HeadImageHeight);                 [BGView addSubview:headImageView];        //        nameLabel=[[UILabel alloc]init];    nameLabel.text=@"Alex";    nameLabel.textAlignment=NSTextAlignmentCenter;    nameLabel.frame=CGRectMake((KScreen_Width-HeadImageHeight)/2, CGRectGetMaxY(headImageView.frame), HeadImageHeight, 20);    nameLabel.backgroundColor=[UIColor whiteColor];    [BGView addSubview:nameLabel];            titleLabel=[[UILabel alloc]initWithFrame:CGRectMake(0, 0, 100, 30)];    titleLabel.textColor=[UIColor whiteColor];    titleLabel.text=@"title";       titleLabel.textAlignment=NSTextAlignmentCenter;        self.navigationItem.titleView=titleLabel;     titleLabel.alpha=0;        leftBtn=[[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 30)];    [leftBtn setTitle:@"left" forState:UIControlStateNormal];    [leftBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];    [leftBtn addTarget:self action:@selector(leftBtnAction) forControlEvents:UIControlEventTouchUpInside];        UIBarButtonItem *leftItem=[[UIBarButtonItem alloc]initWithCustomView:leftBtn];    self.navigationItem.leftBarButtonItem=leftItem;        rightBtn=[[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 30)];    [rightBtn setTitle:@"right" forState:UIControlStateNormal];    [rightBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];    [rightBtn addTarget:self action:@selector(rightBtnAction) forControlEvents:UIControlEventTouchUpInside];            UIBarButtonItem *rightItem=[[UIBarButtonItem alloc]initWithCustomView:rightBtn];    self.navigationItem.rightBarButtonItem=rightItem;    }-(void)leftBtnAction{    NSLog(@"leftClick");}-(void)rightBtnAction{    NSLog(@"rightClick");}#pragma mark - tableViewDelegate&DataSource-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{    return 30;}-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{    UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:@"cell" forIndexPath:indexPath];        if (cell==nil) {        cell=[[UITableViewCell alloc]init];    }        return cell;}-(void)scrollViewDidScroll:(UIScrollView *)scrollView{    CGFloat yOffset  = scrollView.contentOffset.y;    CGFloat xOffset = (yOffset + BackGroupHeight)/2;    NSLog(@"%f",yOffset);    if (yOffset < -BackGroupHeight) {                CGRect rect = imageBG.frame;        rect.origin.y = yOffset;        rect.size.height =  -yOffset ;        rect.origin.x = xOffset;        rect.size.width = KScreen_Width + fabs(xOffset)*2;                imageBG.frame = rect;    }            CGFloat alpha = (yOffset+BackGroupHeight)/BackGroupHeight;    [self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];    titleLabel.alpha=alpha;    alpha=fabs(alpha);    alpha=fabs(1-alpha);       alpha=alpha<0.2? 0:alpha-0.2;            BGView.alpha=alpha;}- (UIImage *)imageWithColor:(UIColor *)color{    // 描述矩形    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);        // 开启位图上下文    UIGraphicsBeginImageContext(rect.size);    // 获取位图上下文    CGContextRef context = UIGraphicsGetCurrentContext();    // 使用color演示填充上下文    CGContextSetFillColorWithColor(context, [color CGColor]);    // 渲染上下文    CGContextFillRect(context, rect);    // 从上下文中获取图片    UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();    // 结束上下文    UIGraphicsEndImageContext();        return theImage;}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end