Cell from nib for UITableView preload - ios

Question

At first I had this code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
DropDownTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"DropDownTableViewCell"];
if (!cell) {
NSArray *topLevelObjects =
[[NSBundle mainBundle] loadNibNamed:#"DropDownView"
owner:self
options:nil];
for (DropDownTableViewCell *object in topLevelObjects) {
if ([object class] == [DropDownTableViewCell class]) {
cell = object;
break;
}
}
NSAssert(cell, #"Cell must not be nil");
}
cell.nameLabel.text = [self.dataSource buttonDownPicker:self stringForRowAtIndexPath:indexPath];
return cell;
}
At first moment when I show tableView and tableView cell's starts loading from nib I have UI freezing for a few seconds (caused by loading from nib for EVERY displayed cell). This can be solved by loading cell from nib earlier:
- (void)awakeFromNib {
DropDownTableViewCell *cell = [[[NSBundle mainBundle] loadNibNamed:#"DropDownView" owner:self options:nil] objectAtIndex:0];
}
But this way looks "hacky". Is there more appropriate solution?
Edit according to given answers:
I've tried to use registerNib forCellIdentifier but it didn't LOAD nib, it just BINDING nib with identifier and at first time when tableView appears all cells causing load nib to memory

Answer 1

This is not "hacky" at all. For loading cells from a nib what you usually do is load the nib and then register the cell for reusable identifier of your choosing. For instance in one of my projects I have a view controller with a table view. In the view did load I call:
[[NSBundle mainBundle] loadNibNamed:#"ChannelListCell" owner:self options:nil];
[self.channelListTableView registerNib:[UINib nibWithNibName:#"ChannelListCell" bundle:nil] forCellReuseIdentifier:#"channelListCell"];
Then in the cell for row at index path:
cell = [tableView dequeueReusableCellWithIdentifier:#"channelListCell" forIndexPath:indexPath];
In your case the dequeued cell is always nil since you did not register it.

Answer 2

Try like this.....
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UINib *nib = [UINib nibWithNibName:#"" bundle:nil];
[self.tblview registerNib:nib forCellReuseIdentifier:#"DropDownTableViewCell"];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
DropDownTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"DropDownTableViewCell"];
return cell;
}

Answer 3

You can register your class first like bellow in your viewDidLoad. It make faster and better
[self.tableViewObject registerClass: [DropDownTableViewCell class]forCellReuseIdentifier:#"DropDownTableViewCellIdentifier"];
And please add following method in your DropDownTableViewCell.m file
-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:#"DropDownTableViewCell" owner:self options:nil];
// Grab a pointer to the first object (presumably the custom cell, as that's all the XIB should contain).
self = [topLevelObjects objectAtIndex:0];
return self;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier=#"DropDownTableViewCellIdentifier";
DropDownTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: CellIdentifier];
//Access all cell properties here.
return cell.
}
Please refer https://stackoverflow.com/a/30954273/914111 for better knowledge.