Reload the model for UITableViewController before [tableview reloadData]

Question

This is my first attempt at developing an iPhone, and I have UITableViewControllerone that will show the data returned from the web service.

In my AppDelegate, I have a timer set, which is called every few seconds and reloads the model. I keep the same link to the object and just update its contents, so I have the same object on any UITableViewControllerthat is currently displayed.

When the data is updated in AppDelegate, I call:

[[(UITableViewController *)[self.navigationController topViewController] tableView] reloadData];

The model is based on a collection of objects file. Each object filehas some properties and flags.

This works well if the current one UITableViewControlleris a simple single-partition table that maps each cell to a sequential index in an array files.

But I have one of UITableViewControllerwhich shows this information fileand, depending on the flag of the object file, will display 2 or 3 sections. I put this logic here:

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    if ([[_file status] intValue] & DOWNLOADING) {
        kIndexTransferSpeed = 1;
        kIndexSettings = 2;
        return 3;
    } else {
        kIndexSettings = 1;
        kIndexTransferSpeed = -1;
        return 2;   
    }
}

So, on this controller, my -tableView:cellForRowAtIndexPath:is just a big statement ifthat will display a property from an object _file, depending on indexPath.

The problem with this approach is that when this table reloads on the device, I really see that it reloads. Section headings flash for a moment, and cells require a little attention. Specifically, if I scroll the table while it reloads.

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, " " , - tableView:cellForRowAtIndexPath:, AppDelegate [tableView reloadData]. " " , , , , .

Answer 1

reloadData , , , , .. , , , .

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, :

- (void)beginUpdates;   // allow multiple insert/delete of rows and sections to be animated simultaneously. Nestable
- (void)endUpdates;     // only call insert/delete/reload calls inside an update block.  otherwise things like row count, etc. may be invalid.

- (void)insertSections:(NSIndexSet *)sections withRowAnimation:(UITableViewRowAnimation)animation;
- (void)deleteSections:(NSIndexSet *)sections withRowAnimation:(UITableViewRowAnimation)animation;
- (void)reloadSections:(NSIndexSet *)sections withRowAnimation:(UITableViewRowAnimation)animation;

- (void)insertRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation;
- (void)deleteRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation;
- (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation;

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