点击 UIBarButtonItem 时从 indexPath 获取 UICollectionViewCell

Question

我创建了一个带有导航栏和 UiCollectionView 的视图控制器。 UI 集合视图包含自定义 UICollectionViewCell。导航栏包含两个 UIBarButton 项目，一个在左角 - 准备转到上一页，另一个项目在右角 - 安排删除 UI CollectionView 中的单元格，如图所示在下图中：

Main Screen

现在我想在点击右上角的 UIBarButtonItem 时删除选定的 UICollectionViewCell。

这是我的 cellForItemAtIndexPath 方法的样子：

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(nonnull NSIndexPath *)indexPath{
self.GlobalIndexPath = indexPath;
MessagesCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"messagesCell" forIndexPath:indexPath];
cell.MessageHeading.text = [self.Message_Heading objectAtIndex:indexPath.row];
cell.MessageSubject.text = [self.Message_Subject objectAtIndex:indexPath.row];
cell.MessageContent.text = [self.Message_Details objectAtIndex:indexPath.row];
[cell.Checkbox setHidden:YES];
[cell.Checkbox setChecked:NO];
}

我尝试了一种解决方案，例如将 Indexpath 声明为全局变量并在按钮事件中使用它，如下所示：

@property (strong,nonatomic) NSIndexPath *GlobalIndexPath;
some other code .......

//When Bin Icon(UIBarButtonItem) Clicked
- (IBAction)DeleteMessages:(id)sender {

[self.view makeToast:@"You clicked delete button !"];

NSIndexPath *indexPath = [self.MessageCollectionView.indexPathsForVisibleItems objectAtIndex:0] ;
BOOL created = YES;
// how to get desired selected cell here to delete
MessagesCollectionViewCell *cell = [self.MessageCollectionView cellForItemAtIndexPath:self.GlobalIndexPath];
if([cell.Checkbox isHidden])
{
    [cell setHidden:YES];
}
else{
    [cell.Checkbox setChecked:NO];
    [cell.Checkbox setHidden:YES];
}
}

没用。

为了显示选中的 UICollectionViewCell，我正在使用@Chris Chris Vasselli's solution

请帮我解决这个问题。提前致谢。

Answer 1

有几个步骤。首先确定选择的indexPath，但是不要假设方法是运行.....

时有选择

// in your button method
NSArray *selection = [self.MessageCollectionView indexPathsForSelectedItems];
if (selection.count) {
    NSIndexPath *indexPath = selection[0];
    [self removeItemAtIndexPath:indexPath];
}

还有两个步骤可以从集合视图中删除项目：从数据源中删除它们，并告诉视图它已更改。

- (void)removeItemAtIndexPath:(NSIndexPath *)indexPath {
    // if your arrays are mutable...
    [self.Message_Heading removeObjectAtIndex:indexPath.row];

    // OR, if the arrays are immutable
    NSMutableArray *tempMsgHeading = [self.Message_Heading mutableCopy];
    [tempMsgHeading removeObjectAtIndex:indexPath.row];
    self.Message_Heading = tempMsgHeading;
    // ...

对每个数据源数组执行上述一项或多项操作。最后一步是通知集合视图数据源已更改，它必须自行更新。有几种方法可以做到这一点。最简单的是：

    // ...
    [self.MessageCollectionView reloadData];

或者，更优雅一点：

    [self.MessageCollectionView deleteItemsAtIndexPaths:@[indexPath]];
}  // end of removeItemAtIndexPath

点击 UIBarButtonItem 时从 indexPath 获取 UICollectionViewCell

Get UICollectionViewCell from indexPath when UIBarButtonItem is tapped

objective-c

uibarbuttonitem

ios

uicollectionview

uicollectionviewcell