以编程方式创建UICollectionView

Question

我正在寻找一个指南或教程,它将向我展示如何仅使用代码设置一个简单的UICollectionView.

我正在浏览苹果网站上的文档,我也使用参考手册.

但我真的可以从一个简单的指南中受益,它可以告诉我如何设置UICollectionView而不必使用Storyboard或XIB/NIB文件 - 但不幸的是,当我搜索时,我能找到的只是具有故事板的教程.

Answer 1

头文件: -

@interface ViewController : UIViewController<UICollectionViewDataSource,UICollectionViewDelegateFlowLayout>
{
    UICollectionView *_collectionView;
}

实施档案: -

- (void)viewDidLoad
{
     [super viewDidLoad];
     self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

     UICollectionViewFlowLayout *layout=[[UICollectionViewFlowLayout alloc] init];
    _collectionView=[[UICollectionView alloc] initWithFrame:self.view.frame collectionViewLayout:layout];
    [_collectionView setDataSource:self];
    [_collectionView setDelegate:self];

    [_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"cellIdentifier"];
    [_collectionView setBackgroundColor:[UIColor redColor]];

    [self.view addSubview:_collectionView];


    // Do any additional setup after loading the view, typically from a nib.
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 15;
}

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];

    cell.backgroundColor=[UIColor greenColor];
    return cell;
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(50, 50);
}

输出---

Answer 2

对于swift4用户: -

class TwoViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: flowLayout)
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "collectionCell")
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.backgroundColor = UIColor.cyan
        self.view.addSubview(collectionView)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 20
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
       var cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionCell", for: indexPath as IndexPath)

       cell.backgroundColor = UIColor.green
       return cell
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
        return CGSize(width: 50, height: 50)
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
    }
}

Answer 3

对于Swift 2.0

而不是实现绘制以下方法所需的方法CollectionViewCells:

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
    {
        return CGSizeMake(50, 50);
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets
    {
        return UIEdgeInsetsMake(5, 5, 5, 5); //top,left,bottom,right
    }

使用 UICollectionViewFlowLayout

func createCollectionView() {
    let flowLayout = UICollectionViewFlowLayout()

    // Now setup the flowLayout required for drawing the cells
    let space = 5.0 as CGFloat

    // Set view cell size
    flowLayout.itemSize = CGSizeMake(50, 50)

    // Set left and right margins
    flowLayout.minimumInteritemSpacing = space

    // Set top and bottom margins
    flowLayout.minimumLineSpacing = space

    // Finally create the CollectionView
    let collectionView = UICollectionView(frame: CGRectMake(10, 10, 300, 400), collectionViewLayout: flowLayout)

    // Then setup delegates, background color etc.
    collectionView?.dataSource = self
    collectionView?.delegate = self
    collectionView?.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "cellID")
    collectionView?.backgroundColor = UIColor.whiteColor()
    self.view.addSubview(collectionView!)
}

然后UICollectionViewDataSource根据需要实现方法:

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 20;
    }
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    var cell:UICollectionViewCell=collectionView.dequeueReusableCellWithReuseIdentifier("collectionCell", forIndexPath: indexPath) as UICollectionViewCell;
    cell.backgroundColor = UIColor.greenColor();
    return cell;
}
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

Answer 4

斯威夫特3

class TwoViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let flowLayout = UICollectionViewFlowLayout()

        let collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: flowLayout)
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "collectionCell")
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.backgroundColor = UIColor.cyan

        self.view.addSubview(collectionView)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
    {
        return 20
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
    {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionCell", for: indexPath as IndexPath)

        cell.backgroundColor = UIColor.green
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
    {
        return CGSize(width: 50, height: 50)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets
    {
        return UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
    }

}

Answer 5

1. 建立@ Warewolf的答案,下一步是创建自己的自定义单元格.

   去File -> New -> File -> User Interface -> Empty -> Call这个笔尖"customNib".

2. 在你customNib拖动一个UICollectionViewCell in.给它重用单元格标识符@"Cell".

3. File -> New -> File -> Cocoa Touch Class -> Class"CustomCollectionViewCell"如果命名为子类UICollectionViewCell.

4. 返回自定义笔尖,单击单元格并创建此自定义类"CustomCollectionViewCell".

5. 转到你的viewDidLoad viewcontroller而不是

   [_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"cellIdentifier"];

   有

   UINib *nib = [UINib nibWithNibName:@"customNib" bundle:nil]; [_collectionView registerNib:nib forCellWithReuseIdentifier:@"Cell"];

6. 另外,更改(到您的新单元格标识符)

   UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];

Answer 6

您可以在uicollection视图中处理自定义单元格，请参见以下代码。

- (void)viewDidLoad
{
  UINib *nib2 = [UINib nibWithNibName:@"YourCustomCell" bundle:nil];
    [CollectionVW registerNib:nib2 forCellWithReuseIdentifier:@"YourCustomCell"];


    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    [flowLayout setItemSize:CGSizeMake(200, 230)];
    flowLayout.minimumInteritemSpacing = 0;
    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
    [CollectionVW setCollectionViewLayout:flowLayout];

    [CollectionVW reloadData];
}

#pragma mark - COLLECTIONVIEW
#pragma mark Collection View CODE

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return Array.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"YourCustomCell";
    YourCustomCell *cell = (YourCustomCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

    cell.MainIMG.image=[UIImage imageNamed:[Array objectAtIndex:indexPath.row]];


    return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
}

#pragma mark Collection view layout things
// Layout: Set cell size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CGSize mElementSize;
    mElementSize=CGSizeMake(kScreenWidth/3.4, 150);
    return mElementSize;
}


- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
    return 5.0;
}

// Layout: Set Edges
- (UIEdgeInsets)collectionView: (UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    if (isIphone5 || isiPhone4)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }
    else if (isIphone6)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }
    else if (isIphone6P)
    {
        return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
    }

    return UIEdgeInsetsMake(15,15,5,15);  // top, left, bottom, right
}