UICollectionView Cell Spacing based on device scre

问题:

I have implemented a UICollectionView, the cell size is w90 h90. When i run it on iPhone 6 i get the proper spacing between cell but when i do it on iPhone 5s i get more spacing between cell. My question is how do i change cell size based on the device screen size, suppose if the cell size was w80 h80 i get proper results on iPhone 5s too. what I'm presently doing is

 override func viewWillAppear(animated: Bool) {

        var scale = UIScreen.mainScreen().scale as CGFloat
        println("Scale :\(scale)")

        var cellSize = (self.collectionViewLayout as UICollectionViewFlowLayout).itemSize
        println("Cell size :\(cellSize)")

        imageSize = CGSizeMake(cellSize.width * scale , cellSize.height * scale)
        println("Image size : \(imageSize)")

    }

// sizeForItemAtIndexPath

  func collectionView(collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
   {

        return imageSize!

   }

Result on iPhone 6 :

Result on iPhone 5s

Objective-C / Swift both fine for solution. Thanks.

回答1:

Step 1: Implement UICollectionViewDelegateFlowLayout(if not done).

Step 2: Use delegate method of UICollectionViewDelegateFlowLayout.

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
return CGSizeMake((UIScreen.mainScreen().bounds.width-15)/4,120); //use height whatever you wants.
}

Step 3: Go to XIB or StoryBoard where you have your CollectionView.

Step 4: In XIB or StoryBoard where you have your CollectionView click on CollectionView.

Step 5: Go to InterfaceBuilder, then in second last tab (ie: Size Inspector) set Min Spacing

For Cells = 5

For Lines = 5

That it.

Note:

• This solution is for if you wants to make spacing between cell = 5.
• If your spacing is different then 5, then you need to change value 15 in delegate method.
• Ex: Spacing between cell = 10, then change delegate 15 to 10x3 = 30

return CGSizeMake((UIScreen.mainScreen().bounds.width-30)/4,120);

• And set Min Spacing

For Cells = 10

For Lines = 10

and vice versa.

Swift 3 Version

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let width = UIScreen.main.bounds.width
    return CGSize(width: (width - 10)/3, height: (width - 10)/3) // width & height are the same to make a square cell
}

回答2:

For a slightly more flexible answer

Allows you to adjust number of columns and spacing, expanding on Zaid Pathan's answer

// MARK: UICollectionViewDelegateFlowLayout delegate method
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
    let cellSpacing = CGFloat(2) //Define the space between each cell
    let leftRightMargin = CGFloat(20) //If defined in Interface Builder for "Section Insets"
    let numColumns = CGFloat(3) //The total number of columns you want

    let totalCellSpace = cellSpacing * (numColumns - 1)
    let screenWidth = UIScreen.mainScreen().bounds.width
    let width = (screenWidth - leftRightMargin - totalCellSpace) / numColumns
    let height = CGFloat(110) //whatever height you want

    return CGSizeMake(width, height);
}

回答3:

I wanted 3 item in a section in Both IPad and iPhone. I worked out using the following code. Hope it helps!

1 ) Implement UICollectionViewDelegateFlowLayout delegate


2 )  var device = UIDevice.currentDevice().model

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
    {
        if (device == "iPad" || device == "iPad Simulator")
        {
            return CGSizeMake((UIScreen.mainScreen().bounds.width-15)/3,230)
        }
        return CGSizeMake((UIScreen.mainScreen().bounds.width-10)/3,120)
    }

回答4:

Objective-c example:

use this function

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
     return CGSizeMake(Your desired width, Your desired height);    
    // example: return CGSizeMake(self.view.frame.size.width-20, 100.f);
}

回答5:

To expand on Tim's answer, there is a small caveat relating to partial point widths: Rounding of partial point widths might cause the width to be wider than will allow the number of desired columns. One way to work around this is to truncate the width using trunc():

 return CGSizeMake(trunc(width), height)