How to hide the line between items in UICollectionView - ios

Question

I'm writing my calendar using UICollectionView.
i don't know why this line come out
this is my code for create UICollectionView
#import "MonthTableView.h"
#import "MonthTableCollectionViewCell.h"
#implementation MonthTableView
static NSString *sCELLIDENTIFIER = #"cellidentifier";
#pragma mark - View Lifecycle
-(MonthTableView *)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
_arr_Week = #[#"日",#"一",#"二",#"三",#"四",#"五",#"六",];
[self initSubView];
}
return self;
}
-(void)initSubView
{
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc]init];
flowLayout.minimumInteritemSpacing = 0;
flowLayout.minimumLineSpacing = 0;
UICollectionView *col_Month = [[UICollectionView alloc]initWithFrame:CGRectMake(5, 5, self.frame.size.width - 10, self.frame.size.height - 10) collectionViewLayout:flowLayout];
col_Month.dataSource = self;
col_Month.delegate = self;
[self addSubview:col_Month];
[col_Month registerClass:[MonthTableCollectionViewCell class] forCellWithReuseIdentifier:sCELLIDENTIFIER];
}
#pragma mark - UICollectionView Delegate
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 2;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
if (section == 0) {
return 7;
}
else {
return 5*7;
}
}
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
CGFloat width = collectionView.frame.size.width / 7;
return CGSizeMake(width, width);
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
MonthTableCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:sCELLIDENTIFIER forIndexPath:indexPath];
//Debug
if (indexPath.section == 0) {
cell.backgroundColor = [UIColor colorWithRed:239/255.0 green:239/255.0 blue:239/255.0 alpha:1];
[cell.btn_Day setTitle:[NSString stringWithFormat:#"%#",_arr_Week[indexPath.row]] forState:UIControlStateNormal];
}
else
{
cell.btn_Day.backgroundColor = [UIColor whiteColor];
[cell.btn_Day setTitle:[NSString stringWithFormat:#"%ld",indexPath.row] forState:UIControlStateNormal];
}
return cell;
}
#end
And here is my Custom cell
#import "MonthTableCollectionViewCell.h"
#implementation MonthTableCollectionViewCell
-(MonthTableCollectionViewCell *)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self initSubViews];
}
return self;
}
-(void)initSubViews
{
_btn_Day = [UIButton buttonWithType:UIButtonTypeSystem];
_btn_Day.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);
[self addSubview:_btn_Day];
}
#end
there is nothing in .h file but declaring vars
BTW i'm using Xcode6.