iOS - 如何获取 tableview 中最后一项的 IndexPath？

Question

I would like to automatically scroll to the end of a table view.

[tableView scrollToRowAtIndexPath:lastIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];

Answer 1

To get a reference to the last row in the last section…

// First figure out how many sections there are
NSInteger lastSectionIndex = [tableView numberOfSections] - 1;

// Then grab the number of rows in the last section
NSInteger lastRowIndex = [tableView numberOfRowsInSection:lastSectionIndex] - 1;

// Now just construct the index path
NSIndexPath *pathToLastRow = [NSIndexPath indexPathForRow:lastRowIndex inSection:lastSectionIndex];

Answer 2

You can get the indexPath of the last row in last section like this.

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:(numberOfRowsInLastSection - 1) inSection:(numberOfSections - 1)];

Here, numberOfSections is the value you return from numberOfSectionsInTableView: method. And, numberOfRowsInLastSection is the value you return from numberOfRowsInSection: method for the last section in the table view.

This can be placed in a subclass or category to make it easy:

-(NSIndexPath*)indexPathForLastRow
{
    return [NSIndexPath indexPathForRow:[self numberOfRowsInSection:self.numberOfSections - 1] - 1 inSection:self.numberOfSections - 1];
}

Answer 3

In swift 3

let lastRowIndex = tableView.numberOfRows(inSection: tableView.numberOfSections-1)

if (indexPath.row == lastRowIndex - 1) {
     print("last row selected")
}

Answer 4

Probably someone will need the same for UICollectionView , so I updated Ryan Grimm 's answer for it:

NSInteger lastSectionIndex = [self.collectionView numberOfSections] - 1;
NSInteger lastItemIndex = [self.collectionView numberOfItemsInSection:lastSectionIndex] - 1;
NSIndexPath *pathToLastItem = [NSIndexPath indexPathForItem:lastItemIndex inSection:lastSectionIndex];

Answer 5

try this:

In cellForRowAtIndexPath

if(indexPath.row == myArray.count -1)

{
     myIndexPath = indexpath;
}

myIndexPath should be object of NSIndexPath

Answer 6

Here is an extension in Swift 4.x that takes into consideration that there may not be any rows, so it avoids out of range crashes.

import UIKit

extension UITableView {
    func lastIndexpath() -> IndexPath {
        let section = max(numberOfSections - 1, 0)
        let row = max(numberOfRows(inSection: section) - 1, 0)

        return IndexPath(row: row, section: section)
    }
}

Then call it from your viewcontroller with:

let lastIndexPath = tableView.lastIndexPath()

Answer 7

Most of the answers here, including the accepted answer, do not take into account the valid cases of a table view with zero sections, or a final section with zero rows.

The best way to represent those situations is using an index of NSNotFound , which is accepted by UIKit in methods such as scrollToRowAtIndexPath:atScrollPosition:animated: .

NSNotFound is a valid row index for scrolling to a section with zero rows.

I use the following method:

- (NSIndexPath *)bottomIndexPathOfTableView:(UITableView *)tableView
{
    NSInteger finalSection = NSNotFound;
    NSInteger finalRow = NSNotFound;

    NSInteger numberOfSections = [tableView numberOfSections];
    if (numberOfSections)
    {
        finalSection = numberOfSections - 1;
        NSInteger numberOfRows = [tableView numberOfRowsInSection:finalSection];
        if (numberOfRows)
        {
            finalRow = numberOfRows - 1;
        }
    }
    return numberOfSections ? [NSIndexPath indexPathForRow:finalRow inSection:finalSection] : nil;
}

Answer 8

It seems like all the solutions don't consider that the last section may have no rows at all . So here is a function which returns the last row in a last non-empty section:

Swift 3:

extension UITableViewDataSource {
    func lastIndexPath(_ tableView: UITableView) -> IndexPath? {
        guard let sections = self.numberOfSections?(in: tableView) else { return nil }
        for section in stride(from: sections-1, through: 0, by: -1) {
            let rows = self.tableView(tableView, numberOfRowsInSection: section)
            if rows > 0 {
                return IndexPath(row: rows - 1, section: section)
            }
        }
        return nil
    }
}

Example:

class ViewController: UIViewController {

    //...

    func scrollToLastRow() {
        if let indexPath = lastIndexPath(tableView) {
            tableView.scrollToRow(at: indexPath, at: .bottom, animated: true)
        }
    }
}

extension ViewController: UITableViewDataSource {
    //required data source methods
}

Answer 9

Swift 3 answer, with out of bounds checks. Implemented as a tableview extension

extension UITableView {

    var lastIndexPath: IndexPath? {

        let lastSectionIndex = numberOfSections - 1
        guard lastSectionIndex >= 0 else { return nil }

        let lastIndexInLastSection = numberOfRows(inSection: lastSectionIndex) - 1
        guard lastIndexInLastSection >= 0 else { return nil }

        return IndexPath(row: lastIndexInLastSection, section: lastSectionIndex)
    }
}

Answer 10

Try this code:

//   get number of section
let indexOfLastSection = self.yourTableView.numberOfSections - 1

// Then get the number of rows in the last section

if indexOfLastSection >= 0{
    let indexOfLastRow = self.yourTableView.numberOfRows(inSection: indexOfLastSection) - 1
    if indexOfLastRow >= 0{
        let pathToLastRow = IndexPath.init(row: indexOfLastRow, section: indexOfLastSection)
    }
}

Answer 11

My Swift 5 implementation ensures a valid IndexPath .

extension UITableView {
    
    /// Returns nil if the table view has no rows.
    func kjy_indexPathOfLastRow() -> IndexPath? {
        let sectionsCount = numberOfSections
        guard sectionsCount > 0 else {
            return nil
        }
        for section in (0..<sectionsCount).reversed() {
            let rowsCount = numberOfRows(inSection: section)
            if rowsCount > 0 {
                return IndexPath(row: rowsCount - 1, section: section)
            }
        }
        return nil
    }
}