UITableViewCell错误iOS7

Question

I have a problem, I have a table and in each cell a UISwitch. When the user clicks the switch I would like to know which cell contained the switch.

The code is working fine in ios6 and in ios 7 breaks:

The code is like this:

-(IBAction) doToggle:(id)sender {
UISwitch *toggle = (UISwitch *)sender;
MyCell *cell = (MyCell *)((UISwitch *)sender).superview.superview;
NSLog(@"=========== CELL %@", cell.description);
NSDictionary *item = [list objectAtIndex:[cell index]]; //breaks in this line

In the NSLog I see the following

iOS6:

<MyCell: 0x858b750; baseClass = UITableViewCell; frame = (0 0; 320 44); autoresize = W; layer = <CALayer: 0x858b890>>

iOS7:

<UITableViewCellScrollView: 0x8e5a290; frame = (0 0; 320 44); autoresize = W+H; gestureRecognizers = <NSArray: 0x8e5a740>; layer = <CALayer: 0x8e5a4c0>; contentOffset: {0, 0}>

Can some one help me with this, Thanks in advance!

Answer 1

I think a much cleaner solution than the tag juggling would be to create a custom cell with a delegate protocol, add a target/action of the method and the cell to the UISwitch and call on the delegate (the view controller) the method -toggleSwitched:(BOOL) switchOnOff onMyCell:(MyCell *) cell and you would implement this delegate method something like:

-(void)toggleSwitched:(BOOL) switchOnOff onMyCell:(MyCell *) cell
{
    NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
    // use indexPath to fetch right element
    // ie:
    if(switchOnOff) {
        NSDictionary *item = list[indexPath.row];
    } else {
        // ??
    }
}

Answer 2

You shouldn't be trying to get your data this way. As you see, the structure of the cell is apparently different in iOS 6 and iOS 7 (which we can't really talk about since iOS 7 is still under NDA). Rather than getting the cell by "climbing up" the subview path, give your switch a tag equal to the indexPath.row, and then use that to query your data source to get the dictionary.

-(IBAction) doToggle:(UISwitch *)sender {

    NSDictionary *item = list[sender.tag];
} 

Answer 3

Before iOS7, the cell's superview was the UITableView that contained it. As of iOS7 GM (so presumably will be in the public release as well) the cell's superview is a UITableViewWrapperView with its superview being the UITableViewCell . There are two solutions to the problem.

Solution #1: Create a UITableViewCell category

@implementation UITableViewCell (RelatedTable)

- (UITableView *)relatedTable
{
    if ([self.superview isKindOfClass:[UITableView class]])
        return (UITableView *)self.superview;
    else if ([self.superview.superview isKindOfClass:[UITableView class]])
        return (UITableView *)self.superview.superview;
    else
    {
        NSAssert(NO, @"UITableView shall always be found.");
        return nil;
    }

}
@end

This is a good drop-in replacement to using cell.superview , makes it easy to refactor your existing code -- -- just search and replace with [cell relatedTable] , and throws in an assert to ensure that if the view hierarchy changes or reverts in the future it will show up immediately in your tests.

Solution #2: Add a Weak UITableView reference to UITableViewCell

@interface SOUITableViewCell

   @property (weak, nonatomic) UITableView *tableView;

@end

This is a much better design, though it will require a bit more code refactoring to use in existing projects. In your tableView:cellForRowAtIndexPath use SOUITableViewCell as your cell class or make sure your custom cell class is subclassed from SOUITableViewCell and assign the tableView to the cell's tableView property. Inside the cell you can then refer to the containing tableview using self.tableView .

Answer 4

Many of the developer used custom view to show custom cell on Table view for older version of iOS. If you are one of them, then you will have to face a problem that your button click action will no longer work with iOS7.

How to resolve this:

You have three options:

Option 1: Create the new lay out with new table cell instead of taking view. and put all layouts again in table cell.

I know, this will require a lot of effort. If you don't want to do this, we have a very small hack for it : option 2

Option 2: Create a IBOutlet for your button and add this button as a subview of your cell's content view.

[self.myCell.contentView addSubview:self.btn_click];

The above line of code will add btn_click as a subview of you content view. Now button click action should work.

Option 3:

The best way :

i) Take An outlet UITableViewCell. ii) Make existing view as subview of new table cell. iii) Disconnect the connection of custom cell to existing view and connect it to new UITableViewCell.

thats it, Your IBAction will work now.

May be you got the crash with error message that " class is not key value coding - compliant .". Check your old view connection and remove all connection having yellow mark.

Answer 5

I got the same problem. this code is not guaranteed " (UITableViewCell *)[[[self superview] superview] superview]; ". You can this code working on iOS7.

-(void)buttonClicked:(id)sender
{
    UIButton *button=(UIButton*)sender;
    UITableViewCell *selectedCell = (UITableViewCell*)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:button.tag inSection:0]];
    NSLog("%@",selectedCell.lblTitle.text);
}

Answer 6

For those people who still like simple and dirty fixes like me i think this will solve your problem!!! cheers!!!!!

// Patch to get the table view cell because in iOS7 the superview is a butch
- (UITableViewCell *) getTableViewCellFromSubview:(UIView*)subview
{
    UITableViewCell* tableViewCell = nil;

    while (subview.superview != Nil) {
        if ([subview.superview isKindOfClass:[UITableViewCell class]]) {
            tableViewCell = (UITableViewCell*)subview.superview;
            break;
        } else {
            subview = subview.superview;
        }
    }

    return tableViewCell;
}

Answer 7

Try this out.It works for me.

NSIndexPath *indexPath;
if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1)
{
    indexPath = [self.tableview indexPathForCell:(UITableViewCell*)[[senderButton superview] superview]];

}
else
{
    indexPath = [self.tableview indexPathForCell:(UITableViewCell*)[[[senderButton superview] superview] superview]];
}

NSLog(@"table row - %d and table column - %d",indexPath.row , indexPath.section);

Answer 8

The API has changed causing a lot of crashes when superview returns unexpected objects. Below is an example of tableview and cell accessors for a custom uiview i'm using as a custom backgroundView for my custom UITableViewCell. This works with both ios6/ios7.

- (UITableView *)tableView
{
    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) {
        return (UITableView *)[self cell].superview;
    } else {
        // Load resources for iOS 7 or later
        return (UITableView *)[self cell].superview.superview;
    }

}

- (UITableViewCell *)cell
{
    UIView *v = self;
    while (v && ![v isKindOfClass:[UITableViewCell class]]) v = v.superview;
    return (UITableViewCell *)v;
}

Answer 9

I solved the same problem by following the solution#1 Answerbot provided. (Sorry, Answerbot, I don't have enough reputation yet to vote up your answer)

However, in this case, we should creat a UIView category:

@implementation UIView (GetCellFromContentviewSubview)
- (UITableViewCell *)getCellFromContentviewSubview
{
    if ([[[self superview] superview] isKindOfClass:[UITableViewCell class]]) {
        return (UITableViewCell *)[[self superview] superview];
    }
    else if ([[[[self superview] superview] superview] isKindOfClass:[UITableViewCell class]]) {
        return (UITableViewCell *)[[[self superview] superview] superview];
    }
    else{
         NSLog(@"something Panic happens");
    }
    return nil;
}

@end

Use (MyCell *)[mySwitch getCellFromContentviewSubview] replace (MyCell *)[[mySwitch superview] superview] , then, you will get your cell.

It seems that the table view cell's hierarchy in iOS7 is different from iOS6, there's a UITableViewCellScrollView between UITableViewCell and UITableViewCellContentView.