CODEWITHSUNDEEP
iosuitableview
Reinhard Männer
Reinhard Männer

Reputation: 15217

UITableView shows sometimes a separating line between the cells, on the iPhone, not on the iPad

I have a tableView with dynamic tableViewCells, and the separator property is set to none.
Each cell has 3 subviews, called here backgroundViews, of the cell height, placed with equal width side by side. They present a background color.
Each of these backgroundViews has an imageView as ist own subview. The imageView has the same size as its backgroundView.
The tableViewCell and its subviews are layed out by autolayout, i.e. the imageViews have margins of 0 to their backgroundView, and the 3 backgroundViews have margins of 0 to the tableViewCell top and bottom, the left backgroundView has a margin of 0 to the left edge of the cell, the right backgroundView has a margin of 0 to the right cell edge, and all 3 backgroundViews have equal widths.

enter image description here

In the simplest case, the image property of the imageViews is nil, so that the colored background of the backgroundViews is visible.
When I run the app on an iPad (simulator or device), everything looks fine.
When I run it on an iPhone (simulator or device), there are sometimes little separating lines between some of the cells, maybe 1 point high (in the screenshot below after the 2nd and the 5th cell).
enter image description here This separating line is not related to the backgroundViews, since these have a background color, and the separating line is white. It is neither related to the tableViewCell, nor the contentView, since both have a clear background color. It is neither related to the tableView itself, since its background color is set to black.
I have no idea where this separating line comes from, nor why it shows up only on the iPhone, and not of the iPad. Any suggestion how I could get rid of these annoying lines is welcome.

Upvotes: 1

Views: 82

Answers (2)

caffeinum
caffeinum

Reputation: 431

Accepted answer didn't work for me. However, setting clipsToBounds property on cells helped

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier( ... )
    ...
    cell.clipsToBounds = true
}

Upvotes: 0

Reinhard Männer
Reinhard Männer

Reputation: 15217

The problem was the following:
I divided the tableViewCell width by 3, and set the tableView's rowHeight property to the same value, to get 3 squares side by side.
On the iPad, the row height was 768/3 = 256, an integer value.
On the iPhone, the row height was 320/3 = 106.66666666666667, a fractional value. Thus, the row height could not be mapped 1:1 to the screen points.
When I rounded the row height by 

self.tableView.rowHeight = ceil(fieldWidth);

the problem disappeared.

Upvotes: 1

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