How to change data of UICollectionView on button click ios? - ios

Question

I am trying to change UICollectionViewCell data on button click(in iPad)?
How to achieve this?
How to send different array count to numberOfItemsInSection on button Click?
In my viewDidLoad:
self.collectionViewImages=[[NSMutableArray alloc]initWithObjects:#"1.jpg",#"2.jpg",#"3.jpg",nil] ;
Then in CollectionViewMethods:
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView
numberOfItemsInSection:(NSInteger)section
{
return [_collectionViewImages count];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:#"Cell"
forIndexPath:indexPath];
NSString *collectionViewImageName=[self.collectionViewImages objectAtIndex:indexPath.row];
UIImageView * collectionImage = (UIImageView*)[myCell viewWithTag:11];
collectionImage.image =[UIImage imageNamed:collectionViewImageName];
return myCell;
}
Then on ButtonClick--
(As there are 4-5 buttons i am collecting tag of each button in NSInteger and using that property in numberOfItemsInSection like this,
-(void)btnTapped:(id)sender{
int tag= [(UIButton *)sender tag];
NSLog(#"Button Pressed%d",tag);
_buttonIndex=tag;
//_buttonIndex is NSInteger property
//If i add object in NSMutableArray and call reloadData my UI hangs here only.
//If I empty my NSMutableArray and add new objects in it and then call reloadData, I am getting NSRangeException.
}
And now i am using this property in numberOfItemsInSection as...
if (_buttonIndex==1){
[collectionImage setImage:[UIImage imageNamed:[_array1 objectAtIndex:indexPath.row]]];
//My _array1 has 4 objects and my collectionViewImages array has 7 objects.
}
i am getting error message as
*** Terminating app due to uncaught exception 'NSRangeException',
reason: '*** -[__NSArrayM objectAtIndex:]: index 4 beyond bounds [0 .. 3]'

Answer 1

well you keep two array with a BOOL and based on taps you relload the UicollectionView first keep two array
Declare BOOL
BOOL isChangeData;
Ex :
self.collectionViewImages=[[NSMutableArray alloc]initWithObjects:#"1.jpg",#"2.jpg",#"3.jpg",nil] ;
self.collectionViewImages1=[[NSMutableArray alloc]initWithObjects:#"4.jpg",#"5.jpg",#"6.jpg",nil] ;
isChangeData = TRUE;
First time set original Data as Datasource
-(NSInteger)collectionView:(UICollectionView *)collectionView
numberOfItemsInSection:(NSInteger)section
{
if(isChangeData){
isChangeData = false;
return [_collectionViewImages1 count];
}
else{
isChangeData = TRUE;
return [_collectionViewImages count];
}
}
in button action Make BOOL true and reload UICOllectionView
-(IBAction)changeData:(id)sender {
[self.CollectionView reloadData];
}
Hope this Works if i did any mistake pls correct me.

Answer 2

I believe you're just simply asking how to add/remove data from a UICollectionView through an IBAction. You would just add an object to your UICollectionView's datasource and reload. Here is an example of adding something:
-(IBAction)addObject:(id)sender {
[self.objectArray addObject:#"new object"];
[self.myCollectionView reloadData];
}