使用runtime自定义的NavigationController
这是现在的许多项目中常见的下拉隐藏nav和nav的颜色渐
变
前提: 需要在stroyboard中给控制器嵌入一个导航控制
- 这里为大家讲一下自定义的NavigationController
- 首先, 在ViewController.h中创建一个自定义的UITableView
#import "ViewController.h"
#import "UINavigationController+Extension.h"
#import "ZJTestViewController.h"
static NSString *const ID = @"cell";
@interface ViewController () <UITableViewDelegate, UITableViewDataSource>
@property (nonatomic, strong) UITableView *tableView;
@end
@implementation ViewController
-(UITableView *)tableView {
if (!_tableView) {
_tableView = [[UITableView alloc] initWithFrame:self.view.bounds];
_tableView.delegate = self;
_tableView.dataSource = self;
[self.view addSubview:_tableView];
}
return _tableView;
}
- (void)viewDidLoad {
[super viewDidLoad];
/** 调用自定义navigationBar */
[self.navigationController.navigationBar setColor:[UIColor redColor] andAlpha:0.0 andScrollView:self.tableView];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 100;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:ID];
}
NSString *string = [NSString stringWithFormat:@"%ld", indexPath.row];
cell.textLabel.text = string;
return cell;
}
// 在这个方法中可以调用push到下一个控制器的方法
- (IBAction)didClickItemButton:(UIBarButtonItem *)sender {
ZJTestViewController *test = [[ZJTestViewController alloc] init];
[self.navigationController pushViewController:test animated:YES];
}
@end
- 然后为navigationBar创建一个分类
- 在分类的.h方法中封装自定义的navigationBar
#import <UIKit/UIKit.h>
@interface UINavigationBar (Extension)
/**
* 封装自定义navigationBar方法
*
* @param color 需要的颜色
* @param alpha 透明度
* @param scrollView 需要滚动的控件
*/
- (void)setColor:(UIColor *)color andAlpha:(CGFloat)alpha andScrollView:(UIScrollView *)scrollView;
@end
- 在.m方法中需要创建所需要的控件和为分类添加属性
#import "UINavigationController+Extension.h"
#import <objc/runtime.h>
static NSString *const customNavkey = @"";
@interface UINavigationBar () <UIScrollViewDelegate>
@property (nonatomic, strong) UIView *alphaView;
@property (nonatomic, strong) UIScrollView *scrollView;
@property (nonatomic, strong) UIColor *navBarColor;
@end
@implementation UINavigationBar (Extension)
-(UIView *)alphaView {
// 这是一个获取值的方法
return objc_getAssociatedObject(self, @selector(alphaView));
}
-(void)setAlphaView:(UIView *)alphaView {
// 这是一个赋值的方法
objc_setAssociatedObject(self, @selector(alphaView), alphaView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
-(UIScrollView *)scrollView {
return objc_getAssociatedObject(self, @selector(scrollView));
}
-(void)setScrollView:(UIScrollView *)scrollView {
/
* 使用runtime创建分类属性
*
* @param self 给哪个对象设置属性
@Selector 这里可以使用_cmd 也可以自定义Key 和使用下面这种方式
* @param scrollView 给属性设置的值
*/
objc_setAssociatedObject(self, @selector(scrollView), scrollView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (UIColor *)navBarColor {
return objc_getAssociatedObject(self, @selector(navBarColor));
}
- (void)setNavBarColor:(UIColor *)navBarColor {
objc_setAssociatedObject(self, @selector(navBarColor), navBarColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (void)setColor:(UIColor *)color andAlpha:(CGFloat)alpha andScrollView:(UIScrollView *)scrollView {
self.navBarColor = color;
self.scrollView = scrollView;
self.scrollView.delegate = self;
if (self.alphaView) {
self.alphaView.alpha = alpha;
}else {
UIImage *image = [UIImage new];
[self setBackgroundImage:image forBarMetrics:UIBarMetricsDefault];
UIView *alphaView = [[UIView alloc] initWithFrame:CGRectMake(0, -20, [UIScreen mainScreen].bounds.size.width, 64)];
alphaView.alpha = alpha;
alphaView.backgroundColor = color;
[self setAlphaView:alphaView];
[self insertSubview:alphaView atIndex:0];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat offsetY = scrollView.contentOffset.y;
CGFloat alpha = offsetY / 380;
// [self setColor:self.navBarColor andAlpha:alpha andScrollView:scrollView];
if (offsetY <= 380) {
// self.navBarView.alpha = alpha;
// self.alphaView.backgroundColor = [UIColor colorWithRed:255.0/255 green:51.0/255 blue:51.0/255 alpha:alpha];
self.alphaView.alpha = alpha;
}else {
self.alphaView.alpha = 0.8;
// self.alphaView.backgroundColor = [UIColor colorWithRed:255.0/255 green:51.0/255 blue:51.0/255 alpha:0.8];
}
NSLog(@"%lf", offsetY);
if (offsetY < 0) {
self.transform = CGAffineTransformMakeTranslation(0, offsetY);
}
}
