iOS_SN_CoreData

Posted 2020-06-18 小小的博客

上一篇是讲怎么进行CoreData的基本操作，这一篇是讲NSFetchedResultsController得到CoreData数据怎么与tableView完美结合，和动画操作的实现。

NSFetchedResultsController的结果与tableView的结合

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [[self.queryData sections] count];
}

- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
    if ([[self.queryData sections] count] > 0) {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.queryData sections] objectAtIndex:section];
        return [sectionInfo numberOfObjects];
    } else
        return 0;
}

　　

NSFetchedResultsControllerDelegate代理方法的实现

CoreData中数据将要改变调用的方法

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
    
    // The fetch controller is about to start sending change notifications, so prepare the table view for updates.
    [self.tableView beginUpdates];
}

CoreData中行数据改变调用的方法可以在数据改变时实现某些动画

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
    
    UITableView *tableView = self.tableView;
    
    switch(type) {
            
        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationRight];
            break;
            
        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationBottom];
            break;
            
        case NSFetchedResultsChangeUpdate:
            [tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
            break;
            
        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
    }
}

CoreData中组的数据改变时调用的方法也可以实现某些动画

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
    switch(type) {
            
        case NSFetchedResultsChangeInsert:
            [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
        case NSFetchedResultsChangeMove:
            break;
        case NSFetchedResultsChangeUpdate:
            break;
        case NSFetchedResultsChangeDelete:
            [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
    }
}

CoreData中的数据已经改变时调用的方法

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
    self.dataList = self.queryData.fetchedObjects.mutableCopy;
    NSLog(@"%@",self.dataList);
    [self.tableView endUpdates];
}

　　

本文GitHub地址https://github.com/zhangkiwi/iOS_SN_CoreData