How to put UITableView always in center of UIView?

Question

I would like to implement a UITableView in the center of a UIView . Initially it has only 2 or 3 rows. When user adds more rows, it would extend in vertical direction, while the whole content remains in the center, as shown as below:

Is it possible to do that with UITableView ?

Answer 1

It can be done using UIScrollView's contentOffset property .

1. Make your tableView's frame sitting in the bounds:

    tableView.frame = self.view.bounds; tableView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;

2. 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); }

3. When you call [tableView reloadData] , just call [self layoutTableView] afterwards.

Answer 2

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

Answer 3

If you don't use your headers in the tableview you can dynamically calculate the height of the cells compared to the tableviews bound height.

Kudos to https://stackoverflow.com/a/15026532/1847601

- (CGFloat) tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
    CGFloat contentHeight = 0.0;
    for (int section = 0; section < [self numberOfSectionsInTableView: tableView]; section++) {
        for (int row = 0; row < [self tableView: tableView numberOfRowsInSection: section]; row++) {
            NSIndexPath *indexPath = [NSIndexPath indexPathForRow: row inSection: section];
            contentHeight += [self tableView: tableView heightForRowAtIndexPath: indexPath];
        }
    }
    return (tableView.bounds.size.height - contentHeight)/2;
}


- (UIView *) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
        UIView *view = [[UIView alloc] initWithFrame: CGRectZero];
        view.backgroundColor = [UIColor clearColor];
        return view;
}

Answer 4

No need to have that bulky logic. Just use the following line in cellForRowAt() :

Swift:

tableView.contentInset = UIEdgeInsets(top: (tableView.bounds.height/2 - cell.bounds.height/2), left: 0, bottom: 0, right: 0)

Objective-C:

tableView.contentInset = UIEdgeInsetsMake((tableView.bounds.height/2 - cell.bounds.height/2), 0, 0, 0);

Answer 5

Swift 3

private func hightTableView() {
    yourTableView.frame = CGRect(x: 0, y: Int((Int(view.frame.height) - rowHeight * yourArrayData.count) / 2), width: widthTable, height: rowHeight * yourArrayData.count)
}

Answer 6

extension UITableView {
    func centeredContent() {
        let size = bounds.size
        let yOffset = (size.height - contentSize.height)/2
        contentInset = yOffset > 0 ? UIEdgeInsets(top: yOffset, left: 0, bottom: 0, right: 0) : .zero
    }
}

final class CenteredContentTableView: UITableView {
    override func layoutSubviews() {
        super.layoutSubviews()
        centeredContent()
    }
}