标签：fan imp xpath com 完全 ios ber 不执行 下拉
最近项目测试出一个隐藏已久的bug，经过多番测试，发现在iOS9下自定义的一个UICollectionViewCell只走一次awakeFromNib。
具体情况是，项目中有一个控制器用到了自定义的UICollectionView，有四组数据，然而有三组自定义的UICollectionViewCell布局和子控件是一样的，所以只注册了两种类型的cell
#import <UIKit/UIKit.h> @interface YimaiDoctorGroupMoreTopicCollectionView : UICollectionView + (instancetype)collectionViewWithObject:(id)object; @end
#define kCollectionviewHeight 96.0 #define kCommonIdentifier @"YimaiDoctorGroupMoreTopicCommonCollectionCell" #define kMyIdentifier @"YimaiDoctorGroupMoreTopicMyCollectionCell" #import "YimaiDoctorGroupMoreTopicCollectionView.h" @implementation YimaiDoctorGroupMoreTopicCollectionView static NSString const *commonIdentifier = @"YimaiDoctorGroupMoreTopicCommonCollectionCell"; static NSString const *myIdentifier = @"YimaiDoctorGroupMoreTopicMyCollectionCell"; + (instancetype)collectionViewWithObject:(id)object { //流水布局 UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init]; layout.scrollDirection = UICollectionViewScrollDirectionHorizontal; CGFloat itemHeight = kScreenH - kCollectionviewHeight - kNavigtaionHeight; layout.itemSize = CGSizeMake(kScreenW, itemHeight); layout.minimumLineSpacing = 0; layout.minimumInteritemSpacing = 0; //初始化 YimaiDoctorGroupMoreTopicCollectionView *collection = [[YimaiDoctorGroupMoreTopicCollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout]; //注册 [collection registerNib:[UINib nibWithNibName:kCommonIdentifier bundle:nil] forCellWithReuseIdentifier:kCommonIdentifier]; [collection registerNib:[UINib nibWithNibName:kMyIdentifier bundle:nil] forCellWithReuseIdentifier:kMyIdentifier]; //分页 collection.pagingEnabled = YES; //数据源，代理 collection.delegate = object; collection.dataSource = object; // collection.backgroundColor = [UIColor clearColor]; return collection; } @end
在所属控制器的数据源方法中，初始化和赋值
#pragma mark - UICollectionViewDelegate - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section { return 4; } - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { static NSString *identifier; if (indexPath.item < 3) { identifier = @"YimaiDoctorGroupMoreTopicCommonCollectionCell"; YimaiDoctorGroupMoreTopicCommonCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath]; cell.type = [NSString stringWithFormat:@"%ld",indexPath.item + 1]; FLOG(@"cell ======== %@", cell); return cell; }else{ identifier = @"YimaiDoctorGroupMoreTopicMyCollectionCell"; YimaiDoctorGroupMoreTopicMyCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath]; cell.type = (int)indexPath.item + 1; return cell; } }
每个自定义的UICollectionViewCell里面添加了UITableView作为子控件，并且能上拉加载，下拉刷新，所以有一些初始化
#pragma mark - life cycle - (void)awakeFromNib { [super awakeFromNib]; //设置tableview [self setTableViewAttributes]; self.page = 1; }
当前控制器里顶部还加了资格按钮，用来点击可以实现UICollectionView的滑动
上面是核心源码，看似很正确的实现，最后却验证在iOS9下“不能滑动”，即看似下面这句话不执行
[self.collectionView setContentOffset:CGPointMake(index * kScreenW, 0) animated:NO];
最后通过各种系统版本机型的调试，验证了，上面的这句setContentOffset没有问题，有问题的是，iOS9上YimaiDoctorGroupMoreTopicCommonCollectionCell的awakeFromNib方法只执行了一次，而在其他的手机版本下走了三次，所以导致当初注册的两种类型的cell，这里三种看似相同的cell现在都是完全一样了，数据都一样。类似于是用的同一个地址，而不是我们认为的，三种长得一样的cell都拥有自己独立的地址，所以才导致看着是没滑动，具体为什么还在不同的系统版本上有这种情况，查了资料也没什么头绪，有了解的伙伴们还请多多指点！！最后只附上解决方法：三种看似相同的cell不复用了，于是有了下面重用标识符的修改
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { static NSString *identifier; if (indexPath.item < 3) { identifier = [NSString stringWithFormat:@"%@-%ld",@"YimaiDoctorGroupMoreTopicCommonCollectionCell", indexPath.item]; YimaiDoctorGroupMoreTopicCommonCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath]; cell.type = [NSString stringWithFormat:@"%ld",indexPath.item + 1]; FLOG(@"cell ======== %@", cell); return cell; }else{ identifier = @"YimaiDoctorGroupMoreTopicMyCollectionCell"; YimaiDoctorGroupMoreTopicMyCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath]; cell.type = (int)indexPath.item + 1; return cell; } }
+ (instancetype)collectionViewWithObject:(id)object { //流水布局 UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init]; layout.scrollDirection = UICollectionViewScrollDirectionHorizontal; CGFloat itemHeight = kScreenH - kCollectionviewHeight - kNavigtaionHeight; layout.itemSize = CGSizeMake(kScreenW, itemHeight); layout.minimumLineSpacing = 0; layout.minimumInteritemSpacing = 0; //初始化 YimaiDoctorGroupMoreTopicCollectionView *collection = [[YimaiDoctorGroupMoreTopicCollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout]; //注册 //解决ios9下 自定义的一个UICollectionViewCell只走一次awakeFromNib for (int i = 0; i < 3; i++) { [collection registerNib:[UINib nibWithNibName:kCommonIdentifier bundle:nil] forCellWithReuseIdentifier:[NSString stringWithFormat:@"%@-%d", @"YimaiDoctorGroupMoreTopicCommonCollectionCell", i]]; } // [collection registerNib:[UINib nibWithNibName:kCommonIdentifier bundle:nil] forCellWithReuseIdentifier:kCommonIdentifier]; [collection registerNib:[UINib nibWithNibName:kMyIdentifier bundle:nil] forCellWithReuseIdentifier:kMyIdentifier]; //分页 collection.pagingEnabled = YES; //数据源，代理 collection.delegate = object; collection.dataSource = object; // collection.backgroundColor = [UIColor clearColor]; return collection; }
iOS9下UICollectionViewCell的awakeFromNib问题
标签：fan imp xpath com 完全 ios ber 不执行 下拉
原文地址：https://www.cnblogs.com/jingxin1992/p/9013298.html
