【移動應(yīng)用開發(fā)技術(shù)】IOS中UICollectionView中Decoration View的使用

【移動應(yīng)用開發(fā)技術(shù)】IOS中UICollectionView中DecorationView的使用

DecorationView是UICollectionView的裝飾視圖。蘋果官方給的案例都沒涉及到這個視圖的使用。沒有具體的細節(jié)。我今天用UICollectionView做了一個簡易的書架。主要是DecorationView的使用方法。效果如下：基本的UICollectionView使用方法請自己查詢。#import"CVViewController.h"#import"CVCell.h"#import"CVLayout.h"@interfaceCVViewController()@end@implementationCVViewController-(void)viewDidLoad{

[superviewDidLoad];

[self.collregisterClass:[CVCellclass]forCellWithReuseIdentifier:@"cell"];

CVLayout*layout=[[CVLayoutalloc]init];

[self.collsetCollectionViewLayout:layout];}-(void)didReceiveMemoryWarning{

[superdidReceiveMemoryWarning];}-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView*)collectionView{

return3;}-(NSInteger)collectionView:(UICollectionView*)collectionViewnumberOfItemsInSection:(NSInteger)section{

return3;}-(UICollectionViewCell*)collectionView:(UICollectionView*)collectionViewcellForItemAtIndexPath:(NSIndexPath*)indexPath{UICollectionViewCell*cell=[collectionViewdequeueReusableCellWithReuseIdentifier:@"cell"forIndexPath:indexPath];returncell;}@end其中CVCell是我自定義的一個UICollectionViewCell其中CVLayout是我自定義的一個UICollectionViewLayout接下來主要看一下自定義的layout#import"CVLayout.h"#import"CVDEView.h"@implementationCVLayout-(void)prepareLayout{

[superprepareLayout];

[self

registerClass:[CVDEView

class]forDecorationViewOfKind:@"CDV"];//注冊DecorationView}-(CGSize)collectionViewContentSize{

return

self.collectionView.frame.size;}-(UICollectionViewLayoutAttributes*)layoutAttributesForItemAtIndexPath:(NSIndexPath*)path{

UICollectionViewLayoutAttributes*attributes=

[UICollectionViewLayoutAttributeslayoutAttributesForCellWithIndexPath:path];

attributes.size=CGSizeMake(215/3.0,303/3.0);

attributes.center=CGPointMake(80*(path.item+1),62.5+125*path.section);

returnattributes;}//DecorationView的布局。-(UICollectionViewLayoutAttributes*)layoutAttributesForDecorationViewOfKind:(NSString*)decorationViewKindatIndexPath:(NSIndexPath*)indexPath{UICollectionViewLayoutAttributes*att=[UICollectionViewLayoutAttributeslayoutAttributesForDecorationViewOfKind:decorationViewKindwithIndexPath:indexPath];

att.frame=CGRectMake(0,(125*indexPath.section)/2.0,320,125);

att.zIndex=-1;returnatt;}-(NSArray*)layoutAttributesForElementsInRect:(CGRect)rect{NSMutableArray*attributes=[NSMutableArrayarray];//把DecorationView的布局加入可見區(qū)域布局。for(inty=0;y<3;y++){NSIndexPath*indexPath=[NSIndexPathindexPathForItem:3inSection:y];

[attributesaddObject:[selflayoutAttributesForDecorationViewOfKind:@"CDV"atIndexPath:indexPath]];

}for(NSIntegeri=0;i<3;i++){for(NSIntegert=0;t<3;t++){NSIndexPath*indexPath=[NSIndexPathindexPathForItem:tinSection:i];

[attributesaddObject:[selflayoutAttributesForItemAtIndexPath:indexPath]];

}

}returnattributes;}下面是最后的DecorationView的設(shè)計。首先要繼承UICollectionReusableView然后@implementationCVDEView-(id)initWithFrame:(CGRect)frame{self=[superinitWithFrame:frame];if(self){UIImageView*p_w_picpathView=[[UIImageViewalloc]initWithFrame:fram