Question

我想在一个视图控制器中放置多个uicollectionview我已成功将它放在故事板中，并且我的代码在.m文件中如下所示。

 -(UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:    (NSIndexPath *)indexPath;
 {  

if (_collectionview.tag==2) {


Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];


 [cell.image setImageWithURL:[NSURL URLWithString:@"http://192.168.0.104:808/Images/Image1.jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];


return cell;

}

if(_collectionview.tag==1)
{
    Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:jerryCellID forIndexPath:indexPath];


    [cell.image1 setImageWithURL:[NSURL URLWithString:@"http://img1.wikia.nocookie.net/__cb20121123214954/tomandjerry/images/a/a8/Jerry_(3).jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.catlabel.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
    return cell;
}
else
{
Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
    [cell.image setImageWithURL:[NSURL URLWithString:@"https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT4RNUL18GXdQt2h9Ay4e7eHwm1lgC1BiRKrZY72Apt7b9cTViR7Q"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
return cell;
} }

以上代码正在运行，但它仅适用于一个集合视图我使用断点调试它，因此它进入第一个return语句。所以代码的另一部分甚至没有运行。所以如何解决这个问题。提前谢谢你：）

Answer 1

确保两个集合视图都设置了正确的委托和数据源。

使用NSLog查找问题所在或缺少哪个部分。

 -(UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:        (NSIndexPath *)indexPath;
{  
    NSLog(@"%d collection view is asking cell",cv.tag);
    if (_collectionview.tag==2) {
        Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
        [cell.image setImageWithURL:[NSURL URLWithString:@"http://192.168.0.104:808/Images/Image1.jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
        return cell;
    }

    if(_collectionview.tag==1)
    {
        Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:jerryCellID forIndexPath:indexPath];
        [cell.image1 setImageWithURL:[NSURL URLWithString:@"http://img1.wikia.nocookie.net/__cb20121123214954/tomandjerry/images/a/a8/Jerry_(3).jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.catlabel.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
        return cell;
    }else{
        Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
        [cell.image setImageWithURL:[NSURL URLWithString:@"https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT4RNUL18GXdQt2h9Ay4e7eHwm1lgC1BiRKrZY72Apt7b9cTViR7Q"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
        return cell;
    } 
}

Answer 2

您需要始终检查在委托或数据源中获取的collectionView实例。因此，在您的情况下，使用cv.tag代替使用属性。 _collectionView是一个属性（也许是IBOutlet），它总是引用您的集合视图中的一个（希望如此）。

为了使代码更加干净，我建议使用单独的类作为集合视图的委托/数据源。因此，在视图控制器中，将集合视图委托给该单独的类而不是self。维护起来会更容易。

Answer 3

尝试以下代码：

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;
{  
    Cell *cell;

    if (collectionView.tag==2) 
    {
        cell = [collectionView dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
        [cell.image setImageWithURL:[NSURL URLWithString:@"http://192.168.0.104:808/Images/Image1.jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
    }
    if(collectionView.tag==1)
    {
        cell = [collectionView dequeueReusableCellWithReuseIdentifier:jerryCellID forIndexPath:indexPath];
        [cell.image1 setImageWithURL:[NSURL URLWithString:@"http://img1.wikia.nocookie.net/__cb20121123214954/tomandjerry/images/a/a8/Jerry_(3).jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.catlabel.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
    }
    else
    {
        cell = [collectionView dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
        [cell.image setImageWithURL:[NSURL URLWithString:@"https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT4RNUL18GXdQt2h9Ay4e7eHwm1lgC1BiRKrZY72Apt7b9cTViR7Q"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
        cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
     } 

    return cell;
}

此代码适用于您。

Answer 4

问题是您正在使用"_collectionView"，这可能是一些全局UICollectionView属性，但此委托方法返回类型为UICollectionView的"cv"。

使用cv代替_collectionView。以下代码工作完美!!

-(UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:    (NSIndexPath *)indexPath;
 {  

if (cv.tag==2) {


Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];


 [cell.image setImageWithURL:[NSURL URLWithString:@"http://192.168.0.104:808/Images/Image1.jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];


return cell;

}

if(cv.tag==1)
{
    Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:jerryCellID forIndexPath:indexPath];


    [cell.image1 setImageWithURL:[NSURL URLWithString:@"http://img1.wikia.nocookie.net/__cb20121123214954/tomandjerry/images/a/a8/Jerry_(3).jpg"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.catlabel.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
    return cell;
}
else
{
Cell *cell = [cv dequeueReusableCellWithReuseIdentifier:kCellID forIndexPath:indexPath];
    [cell.image setImageWithURL:[NSURL URLWithString:@"https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT4RNUL18GXdQt2h9Ay4e7eHwm1lgC1BiRKrZY72Apt7b9cTViR7Q"]placeholderImage:[UIImage imageNamed:@"0.jpg"]];
    cell.label.text = [[recipes valueForKey:@"name"]objectAtIndex:0];
return cell;
} }

iPad中的单个视图控制器中有多个UICOLLECTIONView

4 个答案: