简述UICollectionView 使用

 

 

1、介绍

　　UICollectionView类负责管理数据的有序集合以及以自定义布局的模式来呈现这些数据，它提供了一些经常使用的表格（table）功能，此外还增长了许多单栏布局。UICollectionView支持能够用于实现多列网格、 平铺的布局、 圆形的布局和更多的自定义布局，甚至你能够动态地改变它的布局。

当将一个集合视图添加到您的用户界面，您的应用程序的主要工做是管理与该集合视图关联的数据。集合视图的数据源对象，是一个对象，符合 UICollectionViewDataSource 协议，提供由您的应用程序数据集合中视图分红单个的item，而后能够分为节为演示文稿中获取其数据。item是您想要呈现的数据的最小单位。例如，在照片的应用程序，item多是一个单一的图像。集合视图使用一个cell来呈现item，这是您的数据源配置，并提供 UICollectionViewCell 类的一个实例。

除了将它嵌入在您的用户界面，您可使用 UICollectionView 对象的方法以确保item的可视化表示匹配您的数据源对象中的顺序。所以，每当您添加、 删除或从新排列您的集合中的数据，您可使用此类的方法来插入、 删除和从新排列相应cell的状态。您还使用集合视图对象来管理所选的item。

 

 2、使用

 

　　1.咱们要使用UICollectionView得实现UICollectionViewDataSource, UICollectionViewDelegate,UICollectionViewDelegateFlowLayout这三个协议。UICollectionViewDataSource是它的数据源，UICollectionViewDelegate是它的呈现样式，UICollectionViewDelegateFlowLayout是它的布局模式

 

　　2.初始化，在初始化以前咱们须要常见布局实例

UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];

 

UICollectionView *colView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:layout];

 

　　3.注册UICollectionView使用的cell类型。

【必须先注册，不然会报异常

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'could not dequeue a view of kind: UICollectionElementKindCell with identifier myCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'

】

[colView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"myCell"];

　　4.设置代理　

    colView.delegate = self;
    colView.dataSource = self;

 

 

　　5.实现协议

UICollectionViewDataSource

//配置UICollectionView的每一个section的item数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [[self loadData] count];
}

 

//配置section数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

 

//呈现数据
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellID = @"myCell";
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellID forIndexPath:indexPath];
    cell.backgroundColor = [UIColor redColor];
    return cell;
}

 

UICollectionViewDelegateFlowLayout

//配置每一个item的size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(100, 60);
}

//配置item的边距
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    return UIEdgeInsetsMake(20, 20, 0, 20);
}

 

 效果

咱们明晰地能够看到，它已经进行自动布局，为了更能说明问题，咱们如今将

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(200, 60);
}

 

 

return CGSizeMake(60, 60);

 

UICollectionViewDelegate

//点击item时触发
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    NSLog(@"您点击了item:%@", [[self loadData] objectAtIndex:indexPath.row]);
    [collectionView cellForItemAtIndexPath:indexPath].backgroundColor = [UIColor redColor];
    
}

//当前ite是否能够点击
- (BOOL) collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(nonnull NSIndexPath *)indexPath
{
    if (indexPath.row % 2)
    {
        return YES;
    }
    
    return NO;
}

 

 

咱们也能够经过设置UICollectionViewCell的selectedBackgroundView属性来改变cell选中时的背景视图。

咱们还能够设置哪些cell点击时不高亮，点击时cell的样式和点击后cell的样式

- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.backgroundColor = [UIColor redColor];
}

- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.backgroundColor = [UIColor grayColor];
}

 

 

 

 

 

 

 

 

 

 

 

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自用 Demo-选择器

  1 @interface IncTagViewController ()<UICollectionViewDelegate,UICollectionViewDataSource>
 2 
 3 @end
 4 
 5 @implementation IncTagViewController{  6     
 7     UICollectionView *tagCollectionView;  8     UILabel *tagNameLabel;  9     
 10     
 11     NSMutableArray *selectArr;  12     
 13     NSMutableArray *tagArr;  14     
 15 }  16 
 17 -(void)viewWillAppear:(BOOL)animated{  18     
 19     self.tabBarController.tabBar.hidden = YES;  20 }  21 
 22 
 23 - (void)viewDidLoad {  24  [super viewDidLoad];  25     // Do any additional setup after loading the view.
 26     self.view.backgroundColor = Color(237, 237, 237);  27     [self createNavWtihBg:@"daohang" andLeftBtnName:@"返回" andRightBtnName:@"保存" andTitle:@"感兴趣的行业"];  28     
 29  [self createData];  30    
 31  [self createLayout];  32     
 33 }  34 
 35 
 36 -(void)createData{  37     
 38     
 39     tagArr = [NSMutableArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5",@"6",@"78",@"8",@"9",@"5",@"4",@"2",@"143",@"156",@"131",@"5",@"544",@"64",@"8",@"484",@"5",@"15",@"6",@"548",@"4",@"435",@"15",@"49",@"84",@"654",@"8",@"647",@"65",@"4", nil];  40     
 41 
 42     
 43      selectArr = [[NSMutableArray alloc] initWithCapacity:0];  44     // @"0" 字符串0表示该行是未选中状态  45     // @"1" 字符串1表示该行是选中状态
 46     for (int i = 0; i < tagArr.count; i ++) {  47         //真是数据时，在这里匹配判断是是否相同变成@”1“
 48         [selectArr addObject:@"0"];  49  }  50     
 51     
 52 }  53 
 54 -(void)createLayout{  55     UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];  56     tagCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT-64) collectionViewLayout:layout];  57     [tagCollectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"CollectionViewCell"];  58     tagCollectionView.backgroundColor = [UIColor clearColor];  59     tagCollectionView.dataSource = self;  60     tagCollectionView.delegate = self;  61  [self.view addSubview:tagCollectionView];  62     
 63 }  64 
 65 //配置UICollectionView的每一个section的item数
 66 - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{  67     return tagArr.count;  68 }  69 
 70 
 71 
 72 //配置每一个item的size
 73 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{  74     return CGSizeMake((SCREEN_WIDTH-50)/4, 34);  75 }  76 
 77 //配置item的边距
 78 - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{  79     return UIEdgeInsetsMake(20, 10, 0, 10);  80 }  81 
 82 
 83 //呈现数据
 84 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{  85     
 86         
 87     UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CollectionViewCell" forIndexPath:indexPath];  88     cell.backgroundColor = [UIColor whiteColor];  89     tagNameLabel = [TXFactory createLabelWithFrame:CGRectMake(0, 0, (SCREEN_WIDTH-50)/4, 34) Font:14.f Text:tagArr[indexPath.row] bgColor:[UIColor clearColor] textColor:[UIColor lightGrayColor]];  90     tagNameLabel.textAlignment = 1;  91     tagNameLabel.tag = indexPath.row+100;  92 
 93     //根据状态来展现
 94     if ([selectArr[indexPath.row] isEqualToString:@"0"]) {  95         tagNameLabel.textColor = [UIColor lightGrayColor];  96     }else{  97        tagNameLabel.textColor = [UIColor orangeColor];  98  }  99 
100  [cell.contentView addSubview:tagNameLabel]; 101     
102     return cell; 103 } 104 
105 //点击item时触发
106 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ 107     NSLog(@"您点击了item:%ld", (long)indexPath.row); 108     
109     NSString *stateStr = selectArr[indexPath.row]; 110     NSString *changeStateStr; 111     //连续点击的时候，两种状态进行切换
112     if ([stateStr isEqualToString:@"0"]) { 113         
114         
115      UILabel *find_label = (UILabel *)[self.view viewWithTag:indexPath.row+100]; find_label.textColor = [UIColor orangeColor]; 116         
117         changeStateStr = @"1"; 118         
119     } else { 120     UILabel *find_label = (UILabel *)[self.view viewWithTag:indexPath.row+100]; find_label.textColor = [UIColor lightGrayColor]; 121         
122         changeStateStr = @"0"; 123  } 124     
125     
126  [selectArr replaceObjectAtIndex:indexPath.row withObject:changeStateStr]; 127 
128     
129     
130 }