UITableView Insert More Rows While Keeping The Already Fetched Ones - iphone

Question

Below is the function that i am using to get and parse different pages of the feed.
- (void)getFeed:(NSInteger) pageNumber
{
collectedData = [[NSMutableData alloc] init];
NSString *urlStr =[NSString stringWithFormat:#"http://sitename.com/feed/?paged=%d", pageNumber];
NSURL *url = [NSURL URLWithString:urlStr];
NSURLRequest *req = [NSURLRequest requestWithURL:url];
conn = [[NSURLConnection alloc] initWithRequest:req delegate:self startImmediately:YES];
}
When user scrolls down to the bottom of tableview, i use the below function to access the second page of feed and so on by incrementing the counter:
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
float endScrolling = scrollView.contentOffset.y + scrollView.frame.size.height;
if (endScrolling >= scrollView.contentSize.height)
{
counter ++;
[self getFeed:counter];
}
}
The issue is when instead of loading it below the already fetched items, it reloads the tableview to show the new page items and old ones disappear. I want to load new page items below the existing ones to have infinite scroll. How can i do that?

Answer 1

It feels bad to answer your own question, but taking help from another forum, i was able to figure out the answer.
The tableview controller was not in sync with the mutable array, so i created another and append both arrays.
Step1: I created a property
#property (nonatomic, readonly) NSMutableArray *moreItems;
Step2: Initialised the array in ViewDidLoad before calling fetchEntries
moreItems = [[NSMutableArray alloc] init];
Step3: In connectionDidFinishLoading, i appended new array 'moreItems' to the previous array 'items'
[moreItems addObjectsFromArray:[channel items]];
Step4: Changed the data source in numberOfRowsInSection from
return [[channel items] count];
to new array
return [moreItems count];
and then in cellForRowAtIndexPath, used the new array
RSSItem *item = [moreItems objectAtIndex:[indexPath row]];

Answer 2

You should use insertRowsAtIndexPaths: withRowAnimation: method of UITableView.
One thing you must take care of is that when you use this method, number rows retuned by tableView:numberOfRowsInSection should be equal to number_of_existing_rows + number_of_newly_inserted_rows

Answer 3

After you finish retrieving the new feed for next page get the objects in an array.
Add these objects from this array to your data source array.
Now insert rows to the table as follows:
[yourTable beginUpdates];
[yourTable insertRowsAtIndexPaths:indexPathsToInsert
withRowAnimation:UITableViewRowAnimationBottom];
[yourTable endUpdates];
where "indexPathsToInsert" is array of NSIndexPath objects starting from the last row in your table and containg indexPaths for your new objects.
Hope this helps.

Answer 4

Hi,
Create a for loop, with the starting index is (number of objects in datasource) and number of objects you want to add (count),create the array of indexpaths and call insertRowsAtIndexpaths:withRowAnimation. I hope the code helps you.
NSInteger statingIndex = [self.tableViewDatasource count];
NSInteger noOfObjects = //Get the no.of objects count from getFeed method.
NSMutableArray *indexPaths = [[NSMutableArray alloc] init];
for (NSInteger index = statingIndex; index < statingIndex+noOfObjects; index++) {
[_objects addObject:]; // add the object from getFeed method.
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:index inSection:0];
[indexPaths addObject:indexPath];
[indexPath release];
}
[self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];

Answer 5

Whenever your array gets a new object added you call this
-(void)insertRowInTableView
{
int row = [YourDataSourceArray count];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:0];
NSArray *indexPaths = [NSArray arrayWithObject:indexPath];
[YourTableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationTop];
}
Here YourDataSourceArray is the array from which you are setting your tableview row count/data.
YourTableView is your tableView object name.

Answer 6

This may be because when ever you are getting your data from the webservice you are adding it in the Array you are using to populate the table, by this you will have only new data, what you have to do is you have to append the new data to the array(Make it Mutable Array and append new data) and just use the following line
[your_Table reloadData];
Hope this will help you.

Answer 7

Instead of using scrolling down to load, better use the last row of tableview as "Load More Items" and when the user selected that row, get the new feed and reload the tableview.
And also I have one doubt in your code, everytime in getfeed method, you are creating array
collectedData. I doubt you missing of appending this data to table datasource data,which can cause to show you only recent feed data in tableview. Please check