Tableview does not appeared Until setting a tableFooterView

Question

Here is a example for UItableview within scrollview using autolayout. It works well. But if I remove tableFooterView from UItableview, the UItableview is disppeared.

I want to know why tableview need a tableFooterView here? thank you.

the following is source code :

MyTableView.m file:

@implementation MyTableView
- (CGSize)intrinsicContentSize {
    [self layoutIfNeeded];
    return CGSizeMake(UIViewNoIntrinsicMetric, self.contentSize.height);
}
@end

ViewController.m file:

#import "ViewController.h"
#import "MyTableView.h"

@interface ViewController ()<UITableViewDataSource, UITableViewDelegate>
@end

@implementation ViewController
- (void)loadView {
    UIView *view = [[UIView alloc] init];
    self.view = view;

    UIScrollView *scrollView = [[UIScrollView alloc] init];
    scrollView.translatesAutoresizingMaskIntoConstraints = NO;
    scrollView.backgroundColor = [UIColor cyanColor];
    [view addSubview:scrollView];

    UITableView *tableView = [[MyTableView alloc] init];
    tableView.translatesAutoresizingMaskIntoConstraints = NO;
    tableView.dataSource = self;
    tableView.delegate = self;
    [scrollView addSubview:tableView];

    //why have to need this ?
    tableView.tableFooterView = [[UILabel alloc] init];

    //add constraint
    NSDictionary *views = NSDictionaryOfVariableBindings( scrollView,   tableView );
    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-30-[scrollView]-30-|" options:0 metrics:nil views:views]];
    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[scrollView]|" options:0 metrics:nil views:views]];

    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[tableView]|" options:0 metrics:nil views:views]];
    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[tableView]-0-|" options:0 metrics:nil views:views]];
    [view addConstraint:[NSLayoutConstraint constraintWithItem:tableView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:view attribute:NSLayoutAttributeWidth multiplier:1 constant:0]];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 20;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
    }
    cell.textLabel.text = [NSString stringWithFormat:@"Row %d", indexPath.row];
    return cell;
}
@end

Why do you put your tableview inside a scrollview ? – Petar Jun 28 '15 at 10:22 — Petar, Jun 28 '15 at 10:22

score 1 · Accepted Answer · edited May 23 '17 at 11:43

This is very bad approach. Do not use uitableview inside uiscrollView. See details here

Shortly,

You should not embed UIWebView or UITableView objects in UIScrollView objects. If you do so, unexpected behavior can result because touch events for the two objects can be mixed up and wrongly handled.

So, this problem belongs to what Apple said - unexpected behavior

You may rewrite your code as, for example:

- (void)viewDidLoad {
    [super viewDidLoad];
        UIView *view = [[UIView alloc] init];
        self.view = view;

        UITableView *tableView = [[UITableView alloc] initWithFrame:self.view.frame];
        tableView.translatesAutoresizingMaskIntoConstraints = NO;
        tableView.dataSource = self;
        tableView.delegate = self;
        [view addSubview:tableView];
        //add constraint
        NSDictionary *views = NSDictionaryOfVariableBindings(   tableView );

        [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[tableView]|" options:0 metrics:nil views:views]];
        [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[tableView]-0-|" options:0 metrics:nil views:views]];
        [view addConstraint:[NSLayoutConstraint constraintWithItem:tableView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:view attribute:NSLayoutAttributeWidth multiplier:1 constant:0]];

    }

    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
        return 20;
    }

    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
        if (!cell) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
        }
        cell.textLabel.text = [NSString stringWithFormat:@"Row %d", indexPath.row];
        return cell;
    }

If you still want to add uitableview - your constraints setted up in a wrong way. You should add tableview's constraints to uiscrollview, not uiview, and also add equal height constraint to table view

replace your constraints code with:

NSDictionary *views = NSDictionaryOfVariableBindings( scrollView,   tableView );
    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-30-[scrollView]-30-|" options:0 metrics:nil views:views]];
    [view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[scrollView]|" options:0 metrics:nil views:views]];

    [scrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[tableView]|" options:0 metrics:nil views:views]];
    [scrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[tableView]-0-|" options:0 metrics:nil views:views]];
    [view addConstraint:[NSLayoutConstraint constraintWithItem:tableView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:view attribute:NSLayoutAttributeWidth multiplier:1 constant:0]];
    [view addConstraint:[NSLayoutConstraint constraintWithItem:tableView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:view attribute:NSLayoutAttributeHeight multiplier:1 constant:0]];

@stackfisher, mark it as answer, please, if it was useful for you :) — Doro, Jun 28 '15 at 10:54

Tableview does not appeared Until setting a tableFooterView

1 Answers1