本文实例为大家分享了iOS tableView实现头部拉伸改变，导航条渐变色的具体代码，供大家参考，具体内容如下
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
#import "TableViewController.h"
static NSString *ident = @"cell";
#define RGBA(r,g,b,a) [UIColor colorWithRed:r/255.0f green:g/255.0f blue:b/255.0f alpha:a]
#define RGB(r,g,b) RGBA(r,g,b,1.0f)
#define ZhuTiColor RGB(76,16,198)
#define ZhuTiColorAlpha(alpha) RGBA(76, 16, 198, alpha)
// 判断是否是iPhone X
#define iPhoneX ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(1125, 2436), [[UIScreen mainScreen] currentMode].size) : NO)
// 状态栏高度
#define STATUS_BAR_HEIGHT (iPhoneX ? 44.f : 20.f)
// 导航栏高度
#define NAVIGATION_BAR_HEIGHT (iPhoneX ? 88.f : 64.f)
// tabBar高度
#define TAB_BAR_HEIGHT (iPhoneX ? (49.f + 34.f) : 49.f)
// home indicator
#define HOME_INDICATOR_HEIGHT (iPhoneX ? 34.f : 0.f)
#define ScreenWidth ([UIScreen mainScreen].bounds.size.width)
#define ScreenHeight ([UIScreen mainScreen].bounds.size.height)
#define imageHight 200
@interface TableViewController ()
@property (nonatomic,strong) UIImageView *headImage;
@property (nonatomic, strong) UIView *headerBackView;
@property (nonatomic, strong) UIView *mengView;
@end
@implementation TableViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:ident];
self.view.backgroundColor = [UIColor redColor];
self.tableView.tableHeaderView = self.headerBackView;
[self.headerBackView addSubview:self.headImage];
[self.headImage addSubview:self.mengView];
[self navCleanFromAlpha:0];
}
-(void)navCleanFromAlpha:(CGFloat)alpha
{
[self.navigationController.navigationBar setBackgroundImage:[self createImageWithColor:ZhuTiColorAlpha(alpha)] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.shadowImage = [UIImage new];
}
-(UIImage*) createImageWithColor:(UIColor*) color
{
CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;
}
-(UIImageView *)headImage
{
if(!_headImage)
{
_headImage= [[UIImageView alloc]initWithFrame: self.headerBackView.bounds];
_headImage.image = [UIImage imageNamed:@"1024"];
}
return _headImage;
}
-(UIView *)mengView
{
if (!_mengView)
{
_mengView = [[UIView alloc]initWithFrame:self.headerBackView.bounds];
_mengView.backgroundColor = RGBA(1, 1, 1, 0.1);
}
return _mengView;
}
-(UIView *)headerBackView
{
if (!_headerBackView)
{
_headerBackView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, ScreenWidth, imageHight)];
[_headerBackView setBackgroundColor:[UIColor lightGrayColor]];
}
return _headerBackView;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//---------------------- 图片拉升 -------------------------
//图片高度
CGFloat imageHeight = self.headerBackView.frame.size.height;
//图片宽度
CGFloat imageWidth = ScreenWidth;
//图片上下偏移量
CGFloat imageOffsetY = scrollView.contentOffset.y;
// NSLog(@"图片上下偏移量 imageOffsetY:%f ->",imageOffsetY);
//上移
if (imageOffsetY < 0)
{
CGFloat totalOffset = imageHeight + ABS(imageOffsetY);
CGFloat f = totalOffset / imageHeight;
self.headImage.frame = CGRectMake(-(imageWidth * f - imageWidth) * 0.5, imageOffsetY, imageWidth * f, totalOffset);
self.mengView.frame = self.headImage.bounds;
}
//------------------- 导航条颜色渐变 ----------------------------
CGFloat tableViewOffsetY = [self.tableView rectForSection:0].origin.y - NAVIGATION_BAR_HEIGHT;
CGFloat contentOffsetY = scrollView.contentOffset.y;
if (contentOffsetY >= tableViewOffsetY)
{
// scrollView.contentOffset = CGPointMake(0, tableViewOffsetY); //定位
[self navCleanFromAlpha:1];
}
else
{
CGFloat alpha = scrollView.contentOffset.y/imageHight;
if (alpha >= 1) { alpha = 1; }
if (alpha <= 0) { alpha = 0; }
NSLog(@"%.2f",alpha);
[self navCleanFromAlpha:alpha];
}
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ident forIndexPath:indexPath];
// Configure the cell...
cell.textLabel.text = [NSString stringWithFormat:@"asdada = %zd",indexPath.row];
return cell;
}
|
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/saw471/article/details/80207681