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PONSFetchedResultsController, grouped UITableView, HeaderInSection and NSSortDescriptor
 

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  1. PONSFetchedResultsController, grouped UITableView, HeaderInSection and NSSortDescriptor
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    <p>I have a NSFetchRequest with NSSortDesctriptors attached to a NSFetchedResultController providing data (see table example) for a UITableView which is in grouped mode and displays section headers. </p> <p>I have some problems getting my head around proper sorting to display sections.</p> <p><strong>Data:</strong> </p> <pre><code>+---+----------+------------+----------+ |id | subTitle | groupTitle | distance | +---+----------+------------+----------+ |1 | A | T1 | 1.1 | +---+----------+------------+----------+ |2 | B | T1 | 1.2 | +---+----------+------------+----------+ |3 | C | T1 | 3.0 | +---+----------+------------+----------+ |4 | D | T2 | 1.3 | +---+----------+------------+----------+ |5 | E | T2 | 1.4 | +---+----------+------------+----------+ |6 | F | T3 | 1.5 | +---+----------+------------+----------+ </code></pre> <p><strong>What I have:</strong></p> <p><code>NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"groupTitle" ascending:YES];</code></p> <pre><code>--T1 ------A ------B ------C --T2 ------D ------E --T3 ------F </code></pre> <p><strong>What I want: (sort by distance but group by groupTitle for each following items in same group)</strong></p> <p><code>NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"distance" ascending:YES];</code></p> <pre><code>--T1 ------A ------B --T2 ------D ------E --T3 ------F --T1 ------C </code></pre> <p><strong>How could I achieve this behavior?</strong> probably with the viewForHeaderInSection method? What if the section to be grouped is not in the first hierarchy of the <code>[self.fetchedResultsController sections]</code>?</p> <pre><code>//custom header - (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section { id&lt;NSFetchedResultsSectionInfo&gt; sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section]; SomeObject *cellEntity = (SomeObject *)[[sectionInfo objects] objectAtIndex:0]; //cellEntity.groupTitle is the title return aView; } </code></pre>
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    1. USuser1266222
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      1. PONSFetchedResultsController, grouped UITableView, HeaderInSection and NSSortDescriptor
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      1. VTUpMod
    1. COyou can add a core data entity attribute programmaticly wich represents the sorting that you actually need, but this can't be a solution for larger data sets.
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      1. PONSFetchedResultsController, grouped UITableView, HeaderInSection and NSSortDescriptor
      1. USuser1266222
 

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Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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