How to reload and animate just one UITableView cel

问题:

how can I reload and animate just one cell/row ? Right now i download some files. Everytime a file finished downloading, i call it's finished delegate and call [tableview reload]. But then the whole table reloads. And how can i animate the table, so that it doesn't blink in. For example a fade effect or so.

greets Max

回答1:

Use the following UITableView instance method:

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

You have to specify an NSArray of NSIndexPaths that you want to reload. If you just want to reload. If you only want to reload one cell, then you can supply an NSArray that only holds one NSIndexPath. For example:

NSIndexPath* rowToReload = [NSIndexPath indexPathForRow:3 inSection:0];
NSArray* rowsToReload = [NSArray arrayWithObjects:rowToReload, nil];
[myUITableView reloadRowsAtIndexPaths:rowsToReload withRowAnimation:UITableViewRowAnimationNone];

You can see the UITableViewRowAnimation enum for all the possible ways of animating the row refresh. If you don't want any animation then you can use the value UITableViewRowAnimationNone, as in the example.

Reloading specific rows has a greater advantage than simply getting the animation effect that you'd like. You also get a huge performance boost because only the cells that you really need to be reloaded are have their data refreshed, repositioned and redrawn. Depending on the complexity of your cells, there can be quite an overhead each time you refresh a cell, so narrowing down the amount of refreshes you make is a necessary optimization that you should use wherever possible.

回答2:

If you only need to update the text in the tableview cell..

UITableViewCell *cell = [_myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]];

cell.textLabel.text = [NSString stringWithFormat:@"%i", (int)_targetMaxDistanceSlider.value];

回答3:

Apple Document done it with new syntax

[tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationNone];

回答4:

To reload particular cells in a tableView at given indexPaths, you need to create an array of indexPaths and then call function reloadRowsAtIndexPaths on the tableView.

Here is the example:

Swift:

let indexPathsToReload = [indexPath1, indexPath2, indexPath3]
tableView.reloadRowsAtIndexPaths(indexPathsToReload, withRowAnimation: .None)

Objective C:

NSArray *indexPaths = @[indexPath1, indexPath2, indexPath3];
[self.tableView reloadRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationNone];

or

NSArray *indexPaths = [NSArray arraywithobject:@"indexPath1", @"indexPath2", @"indexPath3",nil];
[self.tableView reloadRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationNone];

回答5:

Swift

You can use

let selectedIndexPath = IndexPath(item:0 , section: 0)
self.tableView.reloadRows(at: [selectedIndexPath], with: .none)

in order to reload a specific cell.