第二十一讲.UICollectionView(集合视图)以及瀑布流效果, 通知中心(NSNotificationCenter).
一.集合视图(UICollectionView)
1.集合视图的概念
2.如何创建
3.集合视图的布局UICollectionViewFlowLayout
4.自定义cell和 布局协议UICollectionViewDelegateFlowLayout
使用时cell一般选择自定义,而在布局时候要使用代理.
UICollectionView的基本使用示例代码分析:
#import "ViewController.h"
#import "CollectionReusableView.h"
@interface ViewController ()<UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout>
@property(nonatomic,strong)UICollectionView *collectionView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self loadCollectionView];
//注册方法创建UICollectionView
[self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"CELL"];
}
-(void)loadCollectionView
{
//布局类 控制每一个item的样式
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
flowLayout.itemSize = CGSizeMake(100, 100);
//改变上下行的大小(默认是10)
flowLayout.minimumLineSpacing = 20;
//设置两个item中间的大小(默认为10)
flowLayout.minimumInteritemSpacing = 37.5;
//控制举例屏幕的距离 上 左 下 右
//flowLayout.sectionInset = UIEdgeInsetsMake(100, 100, 100, 0);
//横向滑动
//flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
self.collectionView = [[UICollectionView alloc]initWithFrame:self.view.frame collectionViewLayout:flowLayout];
//背景色
self.collectionView.backgroundColor = [UIColor whiteColor];
self.collectionView.delegate = self;
self.collectionView.dataSource = self;
[self.view addSubview:self.collectionView];
//注册haeder和footer方法
//给collectionView 注册一个headerView
[self.collectionView registerClass:[CollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"Header"];
//给collectionView 注册一个footerView
[self.collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"Footer"];
}
//返回header和footer 设置header和footer
-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
UICollectionReusableView *header = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"Header" forIndexPath:indexPath];
return header;
} else{
UICollectionReusableView *footer = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"Footer" forIndexPath:indexPath];
return footer;
}
}
//设置collectionView的Footer和header的大小-------UICollectionViewDelegateFlowLayout代理方法----------
//设置collectionView的Footer的大小
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section
{
return CGSizeMake(100, 100);
}
//设置collectionView的header大小
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
{
return CGSizeMake(100, 100);
}
//创建UICollectionView时,需要实现的两个代理方法-----------------------------------
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 100;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
//UICollectionViewCell 没有本身携带的控件,就是一个空白的
//所以在项目中一般都自定义一个UICollectionViewCell
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL" forIndexPath:indexPath];
//设置背景颜色
cell.backgroundColor = [UIColor redColor];
return cell;
}
二.通知中心(NSNotificationCenter)
示例代码:
NetWorkHandle.h
#import <Foundation/Foundation.h>
#import "Model.h"
typedef void(^MyBlock)(id object);
@interface NetWorkHandle : NSObject
+ (NetWorkHandle *)sharedDataBaseHandle;
-(NSInteger)numberOfDataArray;
-(Model *)modelAtIndexWithDataArray:(NSInteger)index;
@end
NetWorkHandle.m文件
#import "NetWorkHandle.h"
@interface NetWorkHandle ()
@property (nonatomic, strong) NSMutableArray *dataArray;
@end
@implementation NetWorkHandle
//单例类实现方法
+ (NetWorkHandle *)sharedDataBaseHandle
{
static NetWorkHandle *dataBaseHandle = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
if(dataBaseHandle == nil){
dataBaseHandle = [[NetWorkHandle alloc] init];
//在单例类中调用解析方法
[dataBaseHandle loadPostSnychronization];
}
});
return dataBaseHandle;
}
//post数据解析
- (void)loadPostSnychronization
{
self.dataArray = [NSMutableArray array];
NSString *str = @"http://project.lanou3g.com/teacher/yihuiyun/lanouproject/activitylist.php";
NSURL *url = [NSURL URLWithString:str];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
if(data != nil){
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
NSArray *arr = dic[@"events"];
for(NSDictionary *dic1 in arr){
Model *model = [[Model alloc] init];
[model setValuesForKeysWithDictionary:dic1];
[self.dataArray addObject:model];
}
//name代表通知的名字,所有注册这个名字的接受通知者,都会接受到这个通知 object 是个双保险 通知中心(广播机制) 发送通知
[[NSNotificationCenter defaultCenter] postNotificationName:@"dataBase" object:nil];
}
NSLog(@"%@",self.dataArray);
}];
}
-(NSInteger)numberOfDataArray
{
return self.dataArray.count;
}
-(Model *)modelAtIndexWithDataArray:(NSInteger)index
{
return self.dataArray[index];
}
@end
ViewController.m文件
#import "ViewController.h"
#import "NetWorkHandle.h"
#import "Model.h"
@interface ViewController ()<UITableViewDataSource,UITableViewDelegate>
@property(nonatomic,strong)UITableView *tableView;
@property(nonatomic,strong)NSMutableArray *dataArray;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self loadTableView];
}
-(void)loadTableView
{
self.tableView = [[UITableView alloc] initWithFrame:self.view.frame style:UITableViewStylePlain];
self.tableView.delegate = self;
self.tableView.dataSource = self;
[self.view addSubview: self.tableView];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"CELL"];
//去获取一个叫做dataBase的通知 如果它发出来了 就触发这个方法
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notic:) name:@"dataBase" object:nil];
}
//通知中心触发方法
-(void)notic:(NSNotificationCenter *)sender
{
NSLog(@"jgdsf");
[self.tableView reloadData];
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//这里调用的是networkhandle的方法 使用单例调用方法
return [[NetWorkHandle sharedDataBaseHandle] numberOfDataArray];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CELL" forIndexPath:indexPath];
//这里调用的是networkhandle的方法 先调用类方法 再调用对象方法
Model *model = [[NetWorkHandle sharedDataBaseHandle] modelAtIndexWithDataArray:indexPath.row];;
cell.textLabel.text = model.title;
return cell;
}
@end
SecdViewController.m文件#import "SecdViewController.h"
#import "NetWorkHandle.h"
@interface SecdViewController ()
@end
@implementation SecdViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
//去获取一个叫做dataBase的通知 如果它发出来了 就出发这个方法
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notic) name:@"dataBase" object:nil];
}
-(void)notic
{
NSLog(@"121");
}
@end
Model.h文件和Model.m文件(模型)
#import <Foundation/Foundation.h>
@interface Model : NSObject
@property(nonatomic,copy)NSString *title;
@end
#import "Model.h"
@implementation Model
-(void)setValue:(id)value forUndefinedKey:(NSString *)key
{
}
@end
