reloadRowsAtIndexPaths cannot reload index path as expected - ios

Question

I add a image as avatar at indexPath [0,0], and use detailLabel display nickname at indexPath [0,1].
When use reloadRowsAtIndexPaths indexPath the indexPath [0,1] get a image...
I find when invoke reloadRowsAtIndexPaths the dequeue cell return nil.
Maybe the [0,0] cell be reuse at [0,1], I don't know why so that.
The code is:
- (void)viewDidLoad {
[super viewDidLoad];
_titles = #[#"Avator", #"Nickname"];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kDelayTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
_avator = [UIImage imageNamed:#"cat"];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kDelayTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
_nickName = #"Smallfly";
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:1 inSection:0];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];
});
});
}
#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return _titles.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *const cellIdenfier = #"cellIdentifier";
// Why reloadRowsAtIndexPaths [0,0] returned cell is nil?
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdenfier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdenfier];
}
if (indexPath.row == 0) {
[self configureCell:cell indexPath:indexPath];
} else {
NSString *nickName = _nickName ?: #"nickname";
cell.detailTextLabel.text = nickName;
}
cell.textLabel.text = _titles[indexPath.row];
return cell;
}
- (void)configureCell:(UITableViewCell *)cell indexPath:(NSIndexPath *)indexPath {
for (UIView *sv in cell.contentView.subviews) {
if ([sv isKindOfClass:[UIImageView class]]) {
[sv removeFromSuperview];
}
}
UIImage *avator = _avator ?: [UIImage imageNamed:#"user_profile_avatar"];
UIImageView *avatorImageView = [[UIImageView alloc] initWithImage:avator];
...
[cell.contentView addSubview:avatorImageView];
}

Answer 1

reloadRowsAtIndexPaths is a void method.
dequeueReusableCell always returns a cell (remove UITableViewCell alloc)
Objective-C
- (void)reloadRowsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths
withRowAnimation:(UITableViewRowAnimation)animation
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:#"reuseIdentifier"
forIndexPath:indexPath];
// Configure the cell...
return cell;
}
Swift 3
open func reloadRows(at indexPaths: [IndexPath],
with animation: UITableViewRowAnimation)
override func tableView(_ tableView: UITableView,
cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell =
tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier",
for: indexPath)
// Configure the cell...
return cell
}
You may want to look at a more recent tutorial or sample code.