导航栏全透明下拉放大图片
@interface ViewController () <UITableViewDataSource, UITableViewDelegate>
@property (nonatomic, strong) UITableView *table;
@property (nonatomic, strong) UIImageView *image;
@property (nonatomic, assign) CGFloat offset;
@end
@implementation ViewController
static NSString *const reuseId = @"cell";
#pragma mark ~~~~~~~~~~ 页面加载 ~~~~~~~~~~
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
self.image = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height / 3)];
self.image.image = [UIImage imageNamed:@"image"];
[self.view addSubview:self.image];
self.table = [[UITableView alloc] initWithFrame:CGRectMake(0, XPF_TopHeight, self.view.frame.size.width, self.view.frame.size.height - XPF_TopHeight) style:UITableViewStylePlain];
self.table.dataSource = self;
self.table.delegate = self;
self.table.backgroundColor = [UIColor clearColor];
self.table.contentInset = UIEdgeInsetsMake(self.view.frame.size.height/3 - XPF_TopHeight, 0, 0, 0);
[self.view addSubview: self.table];
self.offset = self.table.contentOffset.y;
[self.table registerClass:[UITableViewCell class] forCellReuseIdentifier:reuseId];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
//去掉透明后导航栏下边的黑边
[self.navigationController.navigationBar setShadowImage:[[UIImage alloc] init]];
[self.navigationController.navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
}
#pragma mark ~~~~~~~~~~ TableViewDataSource ~~~~~~~~~~
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:reuseId];
cell.textLabel.text = [NSString stringWithFormat:@"第%zdrow",indexPath.row];
return cell;
}
#pragma mark ~~~~~~~~~~ ScrollViewDelegate ~~~~~~~~~~
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat y = scrollView.contentOffset.y;
XPFLog(@"%f---%f",y,self.offset);
CGRect frame = self.image.frame;
if (y > self.offset) {
XPFLog(@"向上");
self.title = @"";
frame.origin.y = self.offset-y;
if (y>=0) {
frame.origin.y = self.offset;
self.title = @"标题";
}
self.image.frame = frame;
}
// tableView设置偏移时不能立马获取他的偏移量，所以一开始获取的offset值为0
else if (self.offset == 0) return;
else {
XPFLog(@"向下");
CGFloat x = self.offset - y;
frame = CGRectMake(-x/2, -x/2, self.view.frame.size.width + x, self.view.frame.size.height/3+x);
self.image.frame = frame;
}
}
