addTarget：action：forControlEvents：无法识别的选择器发送到实例-uitablecell中的uibutton

Question

* EDIT: Sorry, just realised - this code was working fine, until I made the table have three sections. When it was a single section with section headings evrything worked fine when scrolling. Now I have theree sections it crashes when scrolling.*

I'm adding a button to a uitablecell. Crash occurs when table contents extend beyond table height, and the table is scrolled extreme bottom.

From the error it looks as if the UIButton isn't being created, it reports back JobsCell instead...

Also the layout in the custom UITableCell goes awry. it looks like the JobsCell class isn't being initiated for cells that need to be reused and displayed back on screen?

    2014-03-20 15:20:32.080 myApp[52350:60b] mapBtn: <UIButton: 0xa89aff0; frame = (0 0; 59 59); opaque = NO; autoresize = RM+BM; tag = 12; layer = <CALayer: 0xa89b1a0>> 2 1
    2014-03-20 15:20:32.313 myApp[52350:60b] mapBtn: <UIButton: 0xa460620; frame = (0 0; 59 59); opaque = NO; autoresize = RM+BM; tag = 12; layer = <CALayer: 0xa469b60>> 0 11
    2014-03-20 15:20:33.512 myApp[52350:60b] mapBtn: <JobsCell: 0xa761ac0; baseClass = UITableViewCell; frame = (0 775; 320 60); autoresize = W; tag = 12; layer = <CALayer: 0xa761e20>> 0 12
2014-03-20 15:20:33.512 myApp[52350:60b] -[JobsCell addTarget:action:forControlEvents:]: unrecognized selector sent to instance 0xa761ac0
2014-03-20 15:20:33.514 myApp[52350:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[JobsCell addTarget:action:forControlEvents:]: unrecognized selector sent to instance 0xa761ac0'
*** First throw call stack:
(
    0   CoreFoundation                      0x024461e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x020178e5 objc_exception_throw + 44
    2   CoreFoundation                      0x024e3243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
    3   CoreFoundation                      0x0243650b ___forwarding___ + 1019
    4   CoreFoundation                      0x024360ee _CF_forwarding_prep_0 + 14
    5   ESC GasCert                         0x0014a109 -[Home_IPVC tableView:cellForRowAtIndexPath:] + 2873
    6   UIKit                               0x00a5d11f -[UITableView _createPreparedCellForGlobalRow:withIndexPath:] + 412
    7   UIKit                               0x00a5d1f3 -[UITableView _createPreparedCellForGlobalRow:] + 69
    8   UIKit                               0x00a3ede7 -[UITableView _updateVisibleCellsNow:] + 2197
    9   UIKit                               0x00a536a5 -[UITableView layoutSubviews] + 213
    10  UIKit                               0x009d3964 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
    11  libobjc.A.dylib                     0x0202982b -[NSObject performSelector:withObject:] + 70
    12  QuartzCore                          0x0429445a -[CALayer layoutSublayers] + 148
    13  QuartzCore                          0x04288244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
    14  QuartzCore                          0x042880b0 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
    15  QuartzCore                          0x041ee7fa _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 294
    16  QuartzCore                          0x041efb85 _ZN2CA11Transaction6commitEv + 393
    17  QuartzCore                          0x042bccc6 _ZN2CA7Display11DisplayLink14dispatch_itemsEyyy + 474
    18  QuartzCore                          0x042bd147 _ZN2CA7Display16TimerDisplayLink8callbackEP16__CFRunLoopTimerPv + 123
    19  CoreFoundation                      0x02404ac6 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
    20  CoreFoundation                      0x024044ad __CFRunLoopDoTimer + 1181
    21  CoreFoundation                      0x023ec538 __CFRunLoopRun + 1816
    22  CoreFoundation                      0x023eb9d3 CFRunLoopRunSpecific + 467
    23  CoreFoundation                      0x023eb7eb CFRunLoopRunInMode + 123
    24  GraphicsServices                    0x036585ee GSEventRunModal + 192
    25  GraphicsServices                    0x0365842b GSEventRun + 104
    26  UIKit                               0x00964f9b UIApplicationMain + 1225
    27  ESC GasCert                         0x0001626d main + 141
    28  ESC GasCert                         0x00002865 start + 53
)
libc++abi.dylib: terminating with uncaught exception of type NSException

But same code in both classes (except line turning cell clear).

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"JobCell";

    UITableViewCell *cell;
    NSArray *versionCompatibility = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];

    if ( 6 <= [[versionCompatibility objectAtIndex:0] intValue] )
    {
        // iOS6 is installed
        cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    }
    else
    {
        // iOS5 is installed
        cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier ];
    }

    // * ios7 table fix
    [cell setBackgroundColor:[UIColor clearColor]];


    Job *job = 0;
    int jobsaved = 0;
    NSString *jobString = @"";
    NSString *jobPostcode = @"";
    NSString *jobDate = @"";

    // Configure the cell...
    if (indexPath.section==0)
    {
        job = [self.jobs objectAtIndex:indexPath.row];
        jobsaved = job.jobSaved;
        jobString = job.jobAddress;
        jobPostcode = job.jobPostcode;
        jobDate = job.jobDate;
    }
    else if (indexPath.section==1)
    {
        job = [self.jobsCommercial objectAtIndex:indexPath.row];
        jobsaved = job.jobSaved;
        jobString = job.jobAddress;
        jobPostcode = job.jobPostcode;
        jobDate = job.jobDate;
    }
    else if (indexPath.section==2)
    {
        Service *service = [self.jobsServices objectAtIndex:indexPath.row];
        jobsaved = service.jobSaved;
        jobString = service.jobAddress;
        jobPostcode = service.jobPostcode;
        jobDate = service.jobDate;
    }

    UIColor *redcol = [UIColor colorWithRed:0.62745098039216 green:0.15294117647059 blue:0.15686274509804 alpha:1.0];

    jobString = [jobString stringByAppendingString:@", "];
    jobString = [jobString stringByAppendingString:jobPostcode];

    //cell.textLabel.text = jobString;

    UILabel *jobLabel = (UILabel *)[cell viewWithTag:10];
    jobLabel.text = jobString;


    if (jobsaved == 1)
    {
        jobLabel.textColor = redcol;
    }
    else
    {
        jobLabel.textColor = [UIColor blackColor];
    }

    UILabel *dateLabel = (UILabel *)[cell viewWithTag:11];

    if (! [jobDate isEqualToString:@""]) {

        NSDateFormatter *formater = [[NSDateFormatter alloc] init];
        [formater setDateFormat:@"yyyy-MM-dd"];

        NSDate *date2 = [formater dateFromString:jobDate];
        [formater setDateFormat:@"d MMM YYYY"];

        NSString *date = [formater stringFromDate:date2];

        dateLabel.text = date;

    }
    else
    {
        dateLabel.text = @"";
    }

    UIButton *mapBtn = (UIButton *)[cell viewWithTag:12];
    NSLog(@"mapBtn: %@ %d %d",mapBtn, indexPath.section, indexPath.row);
    [mapBtn addTarget:self action:@selector(showMap:) forControlEvents:UIControlEventTouchUpInside];
    cell.tag = indexPath.row;

    return cell;
}

JobsCell.h

#import <UIKit/UIKit.h>

@interface JobsCell : UITableViewCell

@property (nonatomic, strong) IBOutlet UILabel *jobLabel;
@property (nonatomic, strong) IBOutlet UILabel *dateLabel;
@property (nonatomic, strong) IBOutlet UIButton *mapBtn;

@end

JobsCell.m

#import "JobsCell.h"

@implementation JobsCell

@synthesize jobLabel;

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        // Initialization code
    }
    return self;
}

- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
    [super setSelected:selected animated:animated];

    // Configure the view for the selected state
}

@end

Answer 1

from your log we can see tag = 12; has JobsCell object not UIButton

 mapBtn: <JobsCell: 0xa761ac0; baseClass = UITableViewCell; frame = (0 775; 320 60); autoresize = W; **tag = 12;** layer = <CALayer: 0xa761e20>> 0 12

the source of problem in this line cell.tag = indexPath.row; because is can be 12 too

Answer 2

Your cell has sets tag as indexPath.row cell.tag = indexPath.row;

Let's try below

[cell.mapBtn addTarget:self action:@selector(showMap:) forControlEvents:UIControlEventTouchUpInside];

Thanks!

Answer 3

You're trying to get the button by some undefined tag ( 12 ) . You can make your life easier by replacing the following code:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"JobCell";

    JobsCell *cell;
    if ([tableView respondsToSelector:@selector(dequeueReusableCellWithIdentifier:forIndexPath:)])
    {
        // iOS6 is installed
        cell = (JobsCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    }
    else
    {
        // iOS5 is installed
        cell = (JobsCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier ];
    }

    // * ios7 table fix
    [cell setBackgroundColor:[UIColor clearColor]];


    Job *job = nil;
    int jobsaved = 0;
    NSString *jobString = @"";
    NSString *jobPostcode = @"";
    NSString *jobDate = @"";

    // Configure the cell...
    if (indexPath.section==0)
    {
        job = [self.jobs objectAtIndex:indexPath.row];
        jobsaved = job.jobSaved;
        jobString = job.jobAddress;
        jobPostcode = job.jobPostcode;
        jobDate = job.jobDate;
    }
    else if (indexPath.section==1)
    {
        job = [self.jobsCommercial objectAtIndex:indexPath.row];
        jobsaved = job.jobSaved;
        jobString = job.jobAddress;
        jobPostcode = job.jobPostcode;
        jobDate = job.jobDate;
    }
    else if (indexPath.section==2)
    {
        Service *service = [self.jobsServices objectAtIndex:indexPath.row];
        jobsaved = service.jobSaved;
        jobString = service.jobAddress;
        jobPostcode = service.jobPostcode;
        jobDate = service.jobDate;
    }

    UIColor *redcol = [UIColor colorWithRed:0.62745098039216 green:0.15294117647059 blue:0.15686274509804 alpha:1.0];

    jobString = [jobString stringByAppendingString:@", "];
    jobString = [jobString stringByAppendingString:jobPostcode];

    //cell.textLabel.text = jobString;

    UILabel *jobLabel = (UILabel *)[cell viewWithTag:10];
    jobLabel.text = jobString;


    if (jobsaved == 1)
    {
        jobLabel.textColor = redcol;
    }
    else
    {
        jobLabel.textColor = [UIColor blackColor];
    }

    UILabel *dateLabel = (UILabel *)[cell viewWithTag:11];

    if (! [jobDate isEqualToString:@""]) {

        NSDateFormatter *formater = [[NSDateFormatter alloc] init];
        [formater setDateFormat:@"yyyy-MM-dd"];

        NSDate *date2 = [formater dateFromString:jobDate];
        [formater setDateFormat:@"d MMM YYYY"];

        NSString *date = [formater stringFromDate:date2];

        dateLabel.text = date;

    }
    else
    {
        dateLabel.text = @"";
    }

    UIButton *mapBtn = cell.mapBtn;
    NSLog(@"mapBtn: %@ %d %d",mapBtn, indexPath.section, indexPath.row);
    [mapBtn addTarget:self action:@selector(showMap:) forControlEvents:UIControlEventTouchUpInside];
    cell.tag = indexPath.row;

    return cell;
}

Please also note how I tested for which dequeueReusableCell method I called - you should never check system version numbers. And pointers should be set to nil , not 0.