Passing data between viewcontroller through property - ios

Question

I have a dictionary on Viewcontroller A .I am passing it on viewcontroller B.On ViewController A it shows data on the dictionary of viewcontroller B.But ,In Viewcontroller it doesnt show any data in it?
ViewController A:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
TableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
if (cell== nil) {
cell = [[TableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
}
if(_List.count>0) {
[cell setupCell:[_List objectAtIndex:indexPath.row]];
ViewControllerB *vc=[[ViewController alloc]init];
vc.userIdInfo=[_List objectAtIndex:indexPath.row];
}
return cell;
}
ViewController B:
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"_userIdInfo %#",userIdInfo);
if([userIdInfo valueForKey:#"UserID"]) {
[self fetchDataFromServer:getdetail];
}
}
This NSLog(#"_userIdInfo %#",userIdInfo) prints null. while vc.userIdInfo prints dictionary
{
Count = 3;
UserID = "6gdab241-j176-1121-lde2-as8d21f62231";
UserName = "abc#gmail.com";
}

Answer 1

In objective C, cellForRowAtIndexPath methods is used for showing the data.
As per code, you are intiallising the ViewController B in cellForRowAtIndexPath.
it will allocate ViewController B multiple time which lead to memory consumptions.
I would suggest you to initialise in ViewDidLoad of ViewController A.
For Passing the data from A to B, you need to Use didSelectRowAtIndexPath method of UITableViewDelegate.
Example:
ViewController A:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
TableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
if (cell== nil) {
cell = [[TableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
}
if(_List.count>0) {
//Use to show data
cell.textLabel.text = [NSString stringWithFormate:#"%#",[_List objectAtIndex:indexPath.row]]];
// [cell setupCell:[_List objectAtIndex:indexPath.row]];
// ViewControllerB *vc=[[ViewController alloc]init];
// vc.userIdInfo=[_List objectAtIndex:indexPath.row];
}
return cell;
}
ViweController B
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// 1st Type
ViewControllerB *vc=[[ViewController alloc]init];
vc.userIdInfo=[_List objectAtIndex:indexPath.row];
[self.navigartionController pushViewController:aVC animated:YES];
}

Answer 2

You need to do ViewController B initialization in DID select method like below.
Don't initialize it in cellForRowAtIndexPath.
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// 1st Type
ViewControllerB *vc=[[ViewController alloc]init];
vc.userIdInfo=[_List objectAtIndex:indexPath.row];
[self.navigartionController pushViewController:aVC animated:YES];
//2nd Type
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
ViewControllerB *aVC = [storyboard instantiateViewControllerWithIdentifier:#"ViewController"];
aVC.userInfo = <set your data>;
[self.navigartionController pushViewController:aVC animated:YES];
}
Hope this will helps.

Answer 3

The code
ViewControllerB *vc=[[ViewController alloc]init];
vc.userIdInfo=[_List objectAtIndex:indexPath.row];
only creates ViewController; it doesn't present it anywhere. moreover, the instance vc will be deallocated right after you leave the scope of
if(_List.count>0){}
your method
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"_userIdInfo %#",userIdInfo);
if([userIdInfo valueForKey:#"UserID"])
{
[self fetchDataFromServer:getdetail];
}
}
will never be called, because your view will never load.
I assume, that what you really want is to present your vc instance with navigationController instance, or from current viewController
[self.navigationController presentViewController: vc animated: YES completion: nil];