Expand/collapse section in UITableView in iOS

Question

Could somebody tell me the way to perform UITableView expandable/collapsible animations in sections of UITableView as below?

or

Answer 1

// -------------------------------------------------------------------------------
//  tableView:viewForHeaderInSection:
// -------------------------------------------------------------------------------
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {

    UIView *mView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 20, 20)];
    [mView setBackgroundColor:[UIColor greenColor]];

    UIImageView *logoView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 5, 20, 20)];
    [logoView setImage:[UIImage imageNamed:@"carat.png"]];
    [mView addSubview:logoView];

    UIButton *bt = [UIButton buttonWithType:UIButtonTypeCustom];
    [bt setFrame:CGRectMake(0, 0, 150, 30)];
    [bt setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    [bt setTag:section];
    [bt.titleLabel setFont:[UIFont systemFontOfSize:20]];
    [bt.titleLabel setTextAlignment:NSTextAlignmentCenter];
    [bt.titleLabel setTextColor:[UIColor blackColor]];
    [bt setTitle: @"More Info" forState: UIControlStateNormal];
    [bt addTarget:self action:@selector(addCell:) forControlEvents:UIControlEventTouchUpInside];
    [mView addSubview:bt];
    return mView;

}

#pragma mark - Suppose you want to hide/show section 2... then
#pragma mark  add or remove the section on toggle the section header for more info

- (void)addCell:(UIButton *)bt{

    // If section of more information
    if(bt.tag == 2) {

        // Initially more info is close, if more info is open
        if(ifOpen) {
            DLog(@"close More info");

            // Set height of section
            heightOfSection = 0.0f;

            // Reset the parameter that more info is closed now
            ifOpen = NO;
        }else {
            // Set height of section
            heightOfSection = 45.0f;
            // Reset the parameter that more info is closed now
            DLog(@"open more info again");
            ifOpen = YES;
        }
        //[self.tableView reloadData];
        [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:2] withRowAnimation:UITableViewRowAnimationFade];
    }

}// end addCell
#pragma mark -
#pragma mark  What will be the height of the section, Make it dynamic

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{

    if (indexPath.section == 2) {
        return heightOfSection;
    }else {
        return 45.0f;
    }

// vKj

Answer 2

I've used a NSDictionary as datasource, this looks like a lot of code, but it's really simple and works very well! how looks here

I created a enum for the sections

typedef NS_ENUM(NSUInteger, TableViewSection) {

    TableViewSection0 = 0,
    TableViewSection1,
    TableViewSection2,
    TableViewSectionCount
};

sections property:

@property (nonatomic, strong) NSMutableDictionary * sectionsDisctionary;

A method returning my sections:

-(NSArray <NSNumber *> * )sections{

    return @[@(TableViewSection0), @(TableViewSection1), @(TableViewSection2)];
}

And then setup my data soruce:

-(void)loadAndSetupData{

    self.sectionsDisctionary = [NSMutableDictionary dictionary];

    NSArray * sections = [self sections];

    for (NSNumber * section in sections) {

    NSArray * sectionObjects = [self objectsForSection:section.integerValue];

    [self.sectionsDisctionary setObject:[NSMutableDictionary dictionaryWithDictionary:@{@"visible" : @YES, @"objects" : sectionObjects}] forKey:section];
    }
}

-(NSArray *)objectsForSection:(NSInteger)section{

    NSArray * objects;

    switch (section) {

        case TableViewSection0:

            objects = @[] // objects for section 0;
            break;

        case TableViewSection1:

            objects = @[] // objects for section 1;
            break;

        case TableViewSection2:

            objects = @[] // objects for section 2;
            break;

        default:
            break;
    }

    return objects;
}

The next methods, will help you to know when a section is opened, and how to respond to tableview datasource:

Respond the section to datasource:

/**
 *  Asks the delegate for a view object to display in the header of the specified section of the table view.
 *
 *  @param tableView The table-view object asking for the view object.
 *  @param section   An index number identifying a section of tableView .
 *
 *  @return A view object to be displayed in the header of section .
 */
- (UIView *) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section{

    NSString * headerName = [self titleForSection:section];

    YourCustomSectionHeaderClass * header = (YourCustomSectionHeaderClass *)[tableView dequeueReusableHeaderFooterViewWithIdentifier:YourCustomSectionHeaderClassIdentifier];

    [header setTag:section];
    [header addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)]];
    header.title = headerName;
    header.collapsed = [self sectionIsOpened:section];


    return header;
}

/**
 * Asks the data source to return the number of sections in the table view
 *
 * @param An object representing the table view requesting this information.
 * @return The number of sections in tableView.
 */
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
    // Return the number of sections.

    return self.sectionsDisctionary.count;
}

/**
 * Tells the data source to return the number of rows in a given section of a table view
 *
 * @param tableView: The table-view object requesting this information.
 * @param section: An index number identifying a section in tableView.
 * @return The number of rows in section.
 */
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{

    BOOL sectionOpened = [self sectionIsOpened:section];
    return sectionOpened ? [[self objectsForSection:section] count] : 0;
}

Tools:

/**
 Return the section at the given index

 @param index the index

 @return The section in the given index
 */
-(NSMutableDictionary *)sectionAtIndex:(NSInteger)index{

    NSString * asectionKey = [self.sectionsDisctionary.allKeys objectAtIndex:index];

    return [self.sectionsDisctionary objectForKey:asectionKey];
}

/**
 Check if a section is currently opened

 @param section the section to check

 @return YES if is opened
 */
-(BOOL)sectionIsOpened:(NSInteger)section{

    NSDictionary * asection = [self sectionAtIndex:section];
    BOOL sectionOpened = [[asection objectForKey:@"visible"] boolValue];

    return sectionOpened;
}


/**
 Handle the section tap

 @param tap the UITapGestureRecognizer
 */
- (void)handleTapGesture:(UITapGestureRecognizer*)tap{

    NSInteger index = tap.view.tag;

    [self toggleSection:index];
}

Toggle section visibility

/**
 Switch the state of the section at the given section number

 @param section the section number
 */
-(void)toggleSection:(NSInteger)section{

    if (index >= 0){

        NSMutableDictionary * asection = [self sectionAtIndex:section];

        [asection setObject:@(![self sectionIsOpened:section]) forKey:@"visible"];

        [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:section] withRowAnimation:UITableViewRowAnimationFade];
    }
}

Answer 3

Expanding on this answer written in Objective C, I wrote the following for those writing in Swift

The idea is to use sections within the table and set the number of rows in the section to 1 (collapsed) and 3(expanded) when the first row in that section is tapped

The table decides how many rows to draw based on an array of Boolean values

You'll need to create two rows in storyboard and give them the reuse identifiers 'CollapsingRow' and 'GroupHeading'

import UIKit

class CollapsingTVC:UITableViewController{

    var sectionVisibilityArray:[Bool]!// Array index corresponds to section in table

    override func viewDidLoad(){
        super.viewDidLoad()
        sectionVisibilityArray = [false,false,false]
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
    }

    override func numberOfSections(in tableView: UITableView) -> Int{
        return sectionVisibilityArray.count
    }
    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat{
        return 0
    }

    // numberOfRowsInSection - Get count of entries
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        var rowsToShow:Int = 0
        if(sectionVisibilityArray[section]){
            rowsToShow = 3 // Or however many rows should be displayed in that section
        }else{
            rowsToShow = 1
        }
        return rowsToShow
    }// numberOfRowsInSection


    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){
        if(indexPath.row == 0){
            if(sectionVisibilityArray[indexPath.section]){
                sectionVisibilityArray[indexPath.section] = false
            }else{
                sectionVisibilityArray[indexPath.section] = true
            }
            self.tableView.reloadSections([indexPath.section], with: .automatic)
        }
    }

    // cellForRowAtIndexPath - Get table cell corresponding to this IndexPath
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        var cell:UITableViewCell

        if(indexPath.row == 0){
             cell = tableView.dequeueReusableCell(withIdentifier: "GroupHeading", for: indexPath as IndexPath)
        }else{
            cell = tableView.dequeueReusableCell(withIdentifier: "CollapsingRow", for: indexPath as IndexPath)
        }

        return cell

    }// cellForRowAtIndexPath

}

Answer 4

You have to make your own custom header row and put that as the first row of each section. Subclassing the UITableView or the headers that are already there will be a pain. Based on the way they work now, I am not sure you can easily get actions out of them. You could set up a cell to LOOK like a header, and setup the tableView:didSelectRowAtIndexPath to manually expand or collapse the section it is in.

I'd store an array of booleans corresponding the the "expended" value of each of your sections. Then you could have the tableView:didSelectRowAtIndexPath on each of your custom header rows toggle this value and then reload that specific section.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    if (indexPath.row == 0) {
        ///it's the first row of any section so it would be your custom section header

        ///put in your code to toggle your boolean value here
        mybooleans[indexPath.section] = !mybooleans[indexPath.section];

        ///reload this section
        [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];
    }
}

Then set numberOfRowsInSection to check the mybooleans value and return 1 if the section isn't expanded, or 1+ the number of items in the section if it is expanded.

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    if (mybooleans[section]) {
        ///we want the number of people plus the header cell
        return [self numberOfPeopleInGroup:section] + 1;
    } else {
        ///we just want the header cell
        return 1;
    }
}

Also, you will need to update cellForRowAtIndexPath to return a custom header cell for the first row in any section.

Answer 5

I got a nice solution inspired by Apple's Table View Animations and Gestures. I deleted unnecessary parts from Apple's sample and translated it into swift.

I know the answer is quite long, but all the code is necessary. Fortunately, you can just copy&past most of the code and just need to do a bit modification on the step 1 and 3

1.create SectionHeaderView.swift and SectionHeaderView.xib

import UIKit

protocol SectionHeaderViewDelegate {
    func sectionHeaderView(sectionHeaderView: SectionHeaderView, sectionOpened: Int)
    func sectionHeaderView(sectionHeaderView: SectionHeaderView, sectionClosed: Int)
}

class SectionHeaderView: UITableViewHeaderFooterView {

    var section: Int?
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var disclosureButton: UIButton!
    @IBAction func toggleOpen() {
        self.toggleOpenWithUserAction(true)
    }
    var delegate: SectionHeaderViewDelegate?

    func toggleOpenWithUserAction(userAction: Bool) {
        self.disclosureButton.selected = !self.disclosureButton.selected

        if userAction {
            if self.disclosureButton.selected {
                self.delegate?.sectionHeaderView(self, sectionClosed: self.section!)
            } else {
                self.delegate?.sectionHeaderView(self, sectionOpened: self.section!)
            }
        }
    }

    override func awakeFromNib() {
        var tapGesture: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "toggleOpen")
        self.addGestureRecognizer(tapGesture)
        // change the button image here, you can also set image via IB.
        self.disclosureButton.setImage(UIImage(named: "arrow_up"), forState: UIControlState.Selected)
        self.disclosureButton.setImage(UIImage(named: "arrow_down"), forState: UIControlState.Normal)
    }

}

the SectionHeaderView.xib(the view with gray background) should look something like this in a tableview(you can customize it according to your needs, of course):

note:

a) the toggleOpen action should be linked to disclosureButton

b) the disclosureButton and toggleOpen action are not necessary. You can delete these 2 things if you don't need the button.

2.create SectionInfo.swift

import UIKit

class SectionInfo: NSObject {
    var open: Bool = true
    var itemsInSection: NSMutableArray = []
    var sectionTitle: String?

    init(itemsInSection: NSMutableArray, sectionTitle: String) {
        self.itemsInSection = itemsInSection
        self.sectionTitle = sectionTitle
    }
}

3.in your tableview

import UIKit

class TableViewController: UITableViewController, SectionHeaderViewDelegate  {

    let SectionHeaderViewIdentifier = "SectionHeaderViewIdentifier"

    var sectionInfoArray: NSMutableArray = []

    override func viewDidLoad() {
        super.viewDidLoad()

        let sectionHeaderNib: UINib = UINib(nibName: "SectionHeaderView", bundle: nil)
        self.tableView.registerNib(sectionHeaderNib, forHeaderFooterViewReuseIdentifier: SectionHeaderViewIdentifier)

        // you can change section height based on your needs
        self.tableView.sectionHeaderHeight = 30

        // You should set up your SectionInfo here
        var firstSection: SectionInfo = SectionInfo(itemsInSection: ["1"], sectionTitle: "firstSection")
        var secondSection: SectionInfo = SectionInfo(itemsInSection: ["2"], sectionTitle: "secondSection"))
        sectionInfoArray.addObjectsFromArray([firstSection, secondSection])
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return sectionInfoArray.count
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if self.sectionInfoArray.count > 0 {
            var sectionInfo: SectionInfo = sectionInfoArray[section] as! SectionInfo
            if sectionInfo.open {
                return sectionInfo.open ? sectionInfo.itemsInSection.count : 0
            }
        }
        return 0
    }

    override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let sectionHeaderView: SectionHeaderView! = self.tableView.dequeueReusableHeaderFooterViewWithIdentifier(SectionHeaderViewIdentifier) as! SectionHeaderView
        var sectionInfo: SectionInfo = sectionInfoArray[section] as! SectionInfo

        sectionHeaderView.titleLabel.text = sectionInfo.sectionTitle
        sectionHeaderView.section = section
        sectionHeaderView.delegate = self
        let backGroundView = UIView()
        // you can customize the background color of the header here
        backGroundView.backgroundColor = UIColor(red:0.89, green:0.89, blue:0.89, alpha:1)
        sectionHeaderView.backgroundView = backGroundView
        return sectionHeaderView
    }

    func sectionHeaderView(sectionHeaderView: SectionHeaderView, sectionOpened: Int) {
        var sectionInfo: SectionInfo = sectionInfoArray[sectionOpened] as! SectionInfo
        var countOfRowsToInsert = sectionInfo.itemsInSection.count
        sectionInfo.open = true

        var indexPathToInsert: NSMutableArray = NSMutableArray()
        for i in 0..<countOfRowsToInsert {
            indexPathToInsert.addObject(NSIndexPath(forRow: i, inSection: sectionOpened))
        }
        self.tableView.insertRowsAtIndexPaths(indexPathToInsert as [AnyObject], withRowAnimation: .Top)
    }

    func sectionHeaderView(sectionHeaderView: SectionHeaderView, sectionClosed: Int) {
        var sectionInfo: SectionInfo = sectionInfoArray[sectionClosed] as! SectionInfo
        var countOfRowsToDelete = sectionInfo.itemsInSection.count
        sectionInfo.open = false
        if countOfRowsToDelete > 0 {
            var indexPathToDelete: NSMutableArray = NSMutableArray()
            for i in 0..<countOfRowsToDelete {
                indexPathToDelete.addObject(NSIndexPath(forRow: i, inSection: sectionClosed))
            }
            self.tableView.deleteRowsAtIndexPaths(indexPathToDelete as [AnyObject], withRowAnimation: .Top)
        }
    }
}

Answer 6

Some sample code for animating an expand/collapse action using a table view section header is provided by Apple at Table View Animations and Gestures.

The key to this approach is to implement

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section

and return a custom UIView which includes a button (typically the same size as the header view itself). By subclassing UIView and using that for the header view (as this sample does), you can easily store additional data such as the section number.