ios - Add UICollectionView in UICollectionViewCell

Question

I am using Swift to build an iOS application for the Hospital I work at.

Somehow, in a specific feature I have to put a UICollectionView inside the UICollectionViewCell. The one I want to achieve was for every content of the parent UICollectionView (vertical scrolling) would have several children (Which can be scrolled horizontal) depending on the parent row.

For illustration, I have to display list of doctors (name & photo) and then I have to display each of the practice schedule of them below their name and photo. The practice schedule would vary depending on each doctor. So, I have to put it inside the UICollectionView.

I have tried several solutions that I found on the web, but I still cannot approach it.

The most problem that I can't solve was: I don't know where is the place in the code to load the child data source (doctor schedule) and when I could load it, because I can't have two functions like below:

collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell

this is the one I want to achieve

the UIImage and doctor name (UILabel) was in the parent UICollectionViewCell (scroll vertically), and then everything in the box (practice day n practice time) are the child UICollectionView (scroll horizontally)

PS: there are many doctors, and each of the doctor has several practice day.

please help me how to do this

Answer 1

If you really want to insert an collectionView inside a collectionViewCell then there is a pretty simple step. Create an instance of UICollectionView and add it the collectionViewCell. You can use this example if you like.

//
//  ViewController.swift
//  StackOverFlowAnswer
//
//  Created by BIKRAM BHANDARI on 18/6/17.
//  Copyright ? 2017 BIKRAM BHANDARI. All rights reserved.
//

import UIKit

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {

    let cellId = "CellId"; //Unique cell id

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .red; //just to test

        collectionView.register(Cell.self, forCellWithReuseIdentifier: cellId) //register collection view cell class
        setupViews(); //setup all views
    }

    func setupViews() {

        view.addSubview(collectionView); // add collection view to view controller
        collectionView.delegate = self; // set delegate
        collectionView.dataSource = self; //set data source

        collectionView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true; //set the location of collection view
        collectionView.rightAnchor.constraint(equalTo:  view.rightAnchor).isActive = true; // top anchor of collection view
        collectionView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true; // height
        collectionView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true; // width

    }

    let collectionView: UICollectionView = { // collection view to be added to view controller
        let cv = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout()); //zero size with flow layout
        cv.translatesAutoresizingMaskIntoConstraints = false; //set it to false so that we can suppy constraints
        cv.backgroundColor = .yellow; // test
        return cv;
    }();

    //deque cell
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath);
//        cell.backgroundColor = .blue;
        return cell;
    }

    // number of rows
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5;
    }

    //size of each CollecionViewCell
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: view.frame.width, height: 200);
    }
}

// first UICollectionViewCell
class Cell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

    let cellId = "CellId"; // same as above unique id

    override init(frame: CGRect) {
        super.init(frame: frame);

        setupViews();
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellId); //register custom UICollectionViewCell class.
        // Here I am not using any custom class

    }


    func setupViews(){
        addSubview(collectionView);

        collectionView.delegate = self;
        collectionView.dataSource = self;

        collectionView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true;
        collectionView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true;
        collectionView.topAnchor.constraint(equalTo: topAnchor).isActive = true;
        collectionView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true;
    }

    let collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout();
        layout.scrollDirection = .horizontal; //set scroll direction to horizontal
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout);
        cv.backgroundColor = .blue; //testing
        cv.translatesAutoresizingMaskIntoConstraints = false;
        return cv;
    }();

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath);
        cell.backgroundColor = .red;
        return cell;
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5;
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: self.frame.width, height: self.frame.height - 10);
    }
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}