Use of ios UICollectionView

Use of ios UICollectionView

There are two methods to use UICollectionView: one is to inherit UICollectionViewController, which will bring a UICollectionView; the other is to place a view in a common UIViewController.

I prefer the second type. The second method is used to briefly introduce the use of UICollectionView.

1. UIViewController implements delegation. The Code is as follows:

@ Interface YourViewController: UIViewController

2. Declare UICollectionView. The Code is as follows:

@ Property (nonatomic, retain) UICollectionView * myCollectionView;

3. initialize UICollectionView. The Code is as follows:

-(Void) viewDidLoad
{
[Super viewDidLoad];
[Self initConllectionView];
}
-(Void) initConllectionView {
CircleLayout * layout = [[CircleLayout alloc] init];
MyCollectionView = [[UICollectionView alloc] initWithFrame: self. view. bounds collectionViewLayout: layout];
[MyCollectionView registerClass: [UICollectionViewCell class] forCellWithReuseIdentifier: @ "cell"];
MyCollectionView. backgroundColor = [UIColor whiteColor];
MyCollectionView. delegate = self;
MyCollectionView. dataSource = self;
[Self. view addSubview: myCollectionView];
[Layout release];
}

The CircleLayout inherits from UICollectionViewLayout, which is used to display the layout of UICollectionView and some attributes.

4. Implement-(UICollectionViewCell *) collectionView :( UICollectionView *) collectionView cellForItemAtIndexPath :( NSIndexPath *) indexPath;

-(UICollectionViewCell *) collectionView :( UICollectionView *) collectionView cellForItemAtIndexPath :( NSIndexPath *) indexPath {
UICollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier: CELL_STR forIndexPath: indexPath];
For (UIView * view in cell. contentView. subviews ){
If (view ){
[View removeFromSuperview];
}
}
UIImageView * imgView = [[UIImageView alloc] initWithFrame: CGRectMake (0, 0, ITEM_WIDTH, ITEM_WIDTH)];
If (indexPath. row> 4 ){
ImgView. image = [UIImage imageNamed: @ "apple.png"];
} Else {
ImgView. image = [UIImage imageNamed: @ "applec.png"];
}
[Cell. contentView addSubview: imgView];
[ImgView release];
Return cell;
}

5. cell Size

-(CGSize) collectionView :( UICollectionView *) collectionView layout :( UICollectionViewLayout *) collectionViewLayout sizeForItemAtIndexPath :( NSIndexPath *) indexPath {
Return CGSizeMake (130,130 );
}

 

CircleLayout code:

CircleLayout. h

# Import
# Import
@ Interface CircleLayout: UICollectionViewLayout
@ Property (nonatomic, assign) CGPoint center;
@ Property (nonatomic, assign) CGFloat radius;
@ Property (nonatomic, assign) NSInteger cellCount;
@ End

 

CircleLayout. m

 

# Define ITEM_SIZE 130
# Import "CircleLayout. h"

@ Implementation CircleLayout
@ Synthesize cellCount, center, radius;
-(Void) prepareLayout {
[Super prepareLayout];
CGSize size = self. collectionView. frame. size;
CellCount = [self. collectionView numberOfItemsInSection: 0];
Center = CGPointMake (size. width/2, size. height/2 );
Radius = minute (size. width, size. height)/2.5;
}
-(CGSize) collectionViewContentSize {
Return [self collectionView]. frame. size;
}
-(UICollectionViewLayoutAttributes *) layoutAttributesForItemAtIndexPath :( NSIndexPath *) path
{
UICollectionViewLayoutAttributes * attributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath: path];
Attributes. size = CGSizeMake (ITEM_SIZE, ITEM_SIZE );
Attributes. center = CGPointMake (center. x + radius * cosf (2 * path. item * M_PI/cellCount ),

Center. y + radius * sinf (2 * path. item * M_PI/cellCount ));
Return attributes;
}
-(NSArray *) layoutAttributesForElementsInRect :( CGRect) rect {
NSMutableArray * attributes = [NSMutableArray array];
For (NSInteger I = 0; I <self. cellCount; I ++ ){
NSIndexPath * indexPath = [NSIndexPath indexPathForItem: I inSection: 0];
[Attributes addObject: [self layoutAttributesForItemAtIndexPath: indexPath];
}
Return attributes;
}
-(UICollectionViewLayoutAttributes *) initialLayoutAttributesForInsertedItemAtIndexPath :( NSIndexPath *) itemIndexPath {
UICollectionViewLayoutAttributes * attributes = [self layoutAttributesForItemAtIndexPath: itemIndexPath];
Attributes. alpha = 0.0;
Attributes. center = CGPointMake (center. x, center. y );
Return attributes;
}
-(UICollectionViewLayoutAttributes *) finalLayoutAttributesForDeletedItemAtIndexPath :( NSIndexPath *) itemIndexPath
{
UICollectionViewLayoutAttributes * attributes = [self layoutAttributesForItemAtIndexPath: itemIndexPath];
Attributes. alpha = 0.0;
Attributes. center = CGPointMake (center. x, center. y );
Attributes. transform3D = CATransform3DMakeScale (0.1, 0.1, 1.0 );
Return attributes;
}
@ End