How to put UITableView always in center of UIView?
It can be done using UIScrollView's contentOffset
property.
Make your tableView's frame sitting in the bounds:
tableView.frame = self.view.bounds; tableView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
Declare a method -layoutTableView:
- (void)layoutTableView { CGSize contentSize = tableView.contentSize; CGSize boundsSize = tableView.bounds.size; CGFloat yOffset = 0; if(contentSize.height < boundsSize.height) { yOffset = floorf((boundsSize.height - contentSize.height)/2); } tableView.contentOffset = CGPointMake(0, yOffset); }
When you call
[tableView reloadData]
, just call[self layoutTableView]
afterwards.
Another solution is to adjust the content inset of the table view since the content offset solution didn't work for me. Heres the basic idea (inserted into a custom UITableView subclass):
- (void)reloadData {
[super reloadData];
[self centerTableViewContentsIfNeeded];
}
- (void)layoutSubviews {
[super layoutSubviews];
[self centerTableViewContentsIfNeeded];
}
- (void)centerTableViewContentsIfNeeded {
CGFloat totalHeight = CGRectGetHeight(self.bounds);
CGFloat contentHeight = self.contentSize.height;
//If we have less content than our table frame then we can center
BOOL contentCanBeCentered = contentHeight < totalHeight;
if (contentCanBeCentered) {
self.contentInset = UIEdgeInsetsMake(ceil(totalHeight/2.f - contentHeight/2.f), 0, 0, 0);
} else {
self.contentInset = UIEdgeInsetsZero;
}
}
For the Swift-hearted here's a Playground:
import UIKit
import Foundation
import XCPlayground
class CenteredTable: UITableView {
override func reloadData() {
super.reloadData()
centerTableContentsIfNeeded()
}
override func layoutSubviews() {
super.layoutSubviews()
centerTableContentsIfNeeded()
}
func centerTableContentsIfNeeded() {
let totalHeight = CGRectGetHeight(bounds)
let contentHeight = contentSize.height
let contentCanBeCentered = contentHeight < totalHeight
if (contentCanBeCentered) {
contentInset = UIEdgeInsets(top: ceil(totalHeight/2 - contentHeight/2), left: 0, bottom: 0, right: 0);
} else {
contentInset = UIEdgeInsetsZero;
}
}
}
class DataSource: NSObject, UITableViewDataSource {
let items = ["Mr", "Anderson", "Welcome", "Back", "We", "Missed", "You"]
func registerReusableViewsWithTable(tableView: UITableView) {
tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! UITableViewCell
cell.textLabel?.text = items[indexPath.row]
cell.textLabel?.textAlignment = .Center
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
}
let dataSource = DataSource()
let table = CenteredTable(frame: CGRectMake(0, 0, 300, 800), style: UITableViewStyle.Plain)
table.tableFooterView = UIView(frame: CGRectZero)
let container = UIView(frame: table.frame)
container.addSubview(table)
dataSource.registerReusableViewsWithTable(table)
table.dataSource = dataSource
table.reloadData()
XCPShowView("table", container)
container