How to add dynamically rows to a UITableView in iOS? - ios

Question

I'm developing a view controller for a chat application and I want to show a UIViewController that contains a UITableView (where messages are shown with different format [if is your message or if is a message from other person], a UITextField (to write your messages) and a UIButton (to send the message)
I'm using SRWebSocket example but they use a UITableViewController (that runs perfectly but don't allow me to modify tableview size or to add the others components to the view by storyboard)
This is the code that I have in my Controller:
ChatViewController.h
#import <UIKit/UIKit.h>
#import "SRWebSocket.h"
#import "ChatCell.h"
#import "Message.h"
#import "Person.h"
#import "Program.h"
#import "DateFactory.h"
#interface ChatViewController : UIViewController <UITableViewDataSource,UITableViewDelegate,SRWebSocketDelegate, UITextViewDelegate, UITextFieldDelegate>
#property (strong, nonatomic) NSDictionary *programSegue;
#property (retain, nonatomic) IBOutlet UITableView *tableView;
#property (nonatomic, retain) IBOutlet UITextView *inputView;
- (IBAction)goingUp:(id)sender;
#property (weak, nonatomic) IBOutlet UITextField *inputText;
#end
ChatViewController.m
Code that fails:
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:_messages.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
in:
- (void)webSocket:(SRWebSocket *)webSocket didReceiveMessage:(id)message;
{
NSLog(#"Received \"%#\"", message);
NSError *e;
NSDictionary *allJSON =
[NSJSONSerialization JSONObjectWithData: [message dataUsingEncoding:NSUTF8StringEncoding]
options: NSJSONReadingMutableContainers
error: &e];
NSString *kindJSON = [allJSON objectForKey:#"kind"];
NSString *userJSON = [allJSON objectForKey:#"user"];
NSString *messageJSON = [allJSON objectForKey:#"message"];
NSArray *membersJSON = [allJSON objectForKey:#"members"];
DateFactory *dateFactory = [DateFactory alloc];
NSString *formatDate = #"dd/MM/YYYY HH:mm";
NSString *dateString = [dateFactory dateToString:[NSDate date] withFormat:formatDate];
switch([#[#"join", #"talk", #"quit"] indexOfObject:kindJSON]){
// join
case 0:
break;
// talk
case 1:
[_messages addObject:[[Message alloc] initWithMessage:messageJSON fromMe:NO]];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:_messages.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView scrollRectToVisible:self.tableView.tableFooterView.frame animated:YES];
break;
// quit
case 2:
[[self.navigationItem.titleView.subviews objectAtIndex:1] setText:
[NSString stringWithFormat:#"Sin conexión desde %#", dateString]];
break;
}
}
ERROR
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'attempt to insert row 0 into section 0, but there are only 0 rows in section 0 after the update'
Full code:
#import "ChatViewController.h"
#interface ChatViewController ()
#end
#implementation ChatViewController{
SRWebSocket *_webSocket;
NSMutableArray *_messages;
Person *person;
Program *program;
}
#synthesize programSegue;
#synthesize tableView;
#synthesize inputText;
#synthesize inputView = _inputView;
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
return [inputText resignFirstResponder];
}
#pragma mark - View lifecycle
- (void)viewDidLoad;
{
[super viewDidLoad];
[inputText setDelegate:self];
person = [programSegue objectForKey:#"PERSON"];
program = [programSegue objectForKey:#"PROGRAM"];
self.navigationItem.title = person.name;
// Creates picture to be shown in navigation bar
UIButton* picture = (UIButton *) [[UIImageView alloc] initWithImage:[UIImage imageNamed:person.imageURL]];
CGRect buttonFrame = picture.frame;
buttonFrame.size = CGSizeMake(38, 38);
picture.frame = buttonFrame;
UIBarButtonItem *pictureItem = [[UIBarButtonItem alloc] initWithCustomView:picture];
self.navigationItem.rightBarButtonItem = pictureItem;
// Set title and subtitle
CGRect frame = self.navigationController.navigationBar.frame;
UIView *twoLineTitleView = [[UIView alloc] initWithFrame:CGRectMake(CGRectGetWidth(frame), 0, CGRectGetWidth(frame), CGRectGetHeight(frame))];
UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 6, CGRectGetWidth(frame), 20)];
titleLabel.backgroundColor = [UIColor clearColor];
[titleLabel setTextColor:[UIColor whiteColor]];
titleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
[titleLabel setTextAlignment:NSTextAlignmentCenter];
[titleLabel setFont:[UIFont boldSystemFontOfSize:16]];
[titleLabel setShadowColor:[UIColor grayColor]];
titleLabel.text = person.name;
[twoLineTitleView addSubview:titleLabel];
UILabel *subTitleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 26, CGRectGetWidth(frame), 14)];
subTitleLabel.backgroundColor = [UIColor clearColor];
[subTitleLabel setTextColor:[UIColor whiteColor]];
subTitleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
[subTitleLabel setTextAlignment:NSTextAlignmentCenter];
[subTitleLabel setFont:[UIFont boldSystemFontOfSize:12]];
[titleLabel setShadowColor:[UIColor grayColor]];
subTitleLabel.text = #"subtitleg";
[twoLineTitleView addSubview:subTitleLabel];
self.navigationItem.titleView = twoLineTitleView;
// Start messages
_messages = [[NSMutableArray alloc] init];
[self.tableView reloadData];
}
- (void)_reconnect;
{
_webSocket.delegate = nil;
[_webSocket close];
_webSocket = [[SRWebSocket alloc] initWithURLRequest:
[NSURLRequest requestWithURL:
[NSURL URLWithString:
[NSString stringWithFormat:#"ws://81.45.19.228:8000/room/chat?username=enrimr&pid=%#", person.name]]]];
_webSocket.delegate = self;
//self.title = #"Opening Connection...";
[[self.navigationItem.titleView.subviews objectAtIndex:1] setText:#"Conectando..."];
[_webSocket open];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self _reconnect];
}
- (void)reconnect:(id)sender;
{
[self _reconnect];
}
- (void)viewDidAppear:(BOOL)animated;
{
[super viewDidAppear:animated];
[_inputView becomeFirstResponder];
[self.tableView scrollRectToVisible:self.tableView.tableFooterView.frame animated:YES];
}
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
_webSocket.delegate = nil;
[_webSocket close];
_webSocket = nil;
}
#pragma mark - UITableViewController
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
{
return _messages.count;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath;
{
ChatCell *chatCell = (id)cell;
Message *message = [_messages objectAtIndex:indexPath.row];
chatCell.text.text = message.message;
chatCell.date.text = message.fromMe ? #"Me" : #"Other";
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;
{
Message *message = [_messages objectAtIndex:indexPath.row];
ChatCell *cell = (ChatCell *)[self.tableView dequeueReusableCellWithIdentifier:#"programCell" forIndexPath:indexPath];
if (!cell) {
if (message.fromMe){
cell = [[ChatCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"SentCell"];
[cell.text setText:message.message];
[cell.date setText:#"00:00"];
}
else {
cell = [[ChatCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"ReceivedCell"];
[cell.text setText:message.message];
[cell.date setText:#"00:00"];
}
}
return cell;
}
#pragma mark - SRWebSocketDelegate
- (void)webSocketDidOpen:(SRWebSocket *)webSocket;
{
NSLog(#"Websocket Connected");
//self.title = #"Connected!";
[[self.navigationItem.titleView.subviews objectAtIndex:1] setText:#"Conectado"];
}
- (void)webSocket:(SRWebSocket *)webSocket didFailWithError:(NSError *)error;
{
NSLog(#":( Websocket Failed With Error %#", error);
self.title = #"Connection Failed! (see logs)";
_webSocket = nil;
}
- (void)webSocket:(SRWebSocket *)webSocket didReceiveMessage:(id)message;
{
NSLog(#"Received \"%#\"", message);
NSError *e;
NSDictionary *allJSON =
[NSJSONSerialization JSONObjectWithData: [message dataUsingEncoding:NSUTF8StringEncoding]
options: NSJSONReadingMutableContainers
error: &e];
NSString *kindJSON = [allJSON objectForKey:#"kind"];
NSString *userJSON = [allJSON objectForKey:#"user"];
NSString *messageJSON = [allJSON objectForKey:#"message"];
NSArray *membersJSON = [allJSON objectForKey:#"members"];
DateFactory *dateFactory = [DateFactory alloc];
NSString *formatDate = #"dd/MM/YYYY HH:mm";
NSString *dateString = [dateFactory dateToString:[NSDate date] withFormat:formatDate];
switch([#[#"join", #"talk", #"quit"] indexOfObject:kindJSON]){
// join
case 0:
break;
// talk
case 1:
[_messages addObject:[[Message alloc] initWithMessage:messageJSON fromMe:NO]];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:_messages.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView scrollRectToVisible:self.tableView.tableFooterView.frame animated:YES];
break;
// quit
case 2:
[[self.navigationItem.titleView.subviews objectAtIndex:1] setText:
[NSString stringWithFormat:#"Sin conexión desde %#", dateString]];
break;
}
}
- (void)webSocket:(SRWebSocket *)webSocket didCloseWithCode:(NSInteger)code reason:(NSString *)reason wasClean:(BOOL)wasClean;
{
NSLog(#"WebSocket closed");
//self.title = #"Connection Closed! (see logs)";
[[self.navigationItem.titleView.subviews objectAtIndex:1] setText:#"Offline"];
_webSocket = nil;
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
{
if ([text rangeOfString:#"\n"].location != NSNotFound) {
NSString *message = [[textView.text stringByReplacingCharactersInRange:range withString:text] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
[_webSocket send:message];
[_messages addObject:[[Message alloc] initWithMessage:message fromMe:YES]];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:_messages.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView scrollRectToVisible:self.tableView.tableFooterView.frame animated:YES];
textView.text = #"";
return NO;
}
return YES;
}
- (void) animateTextField: (UITextField*) textField up: (BOOL)up
{
const int movementDistance = 218;
const float movementDuration = 0.3f;
int movement = (up ? -movementDistance : movementDistance);
[UIView beginAnimations: #"anim" context: nil];
[UIView setAnimationBeginsFromCurrentState: YES];
[UIView setAnimationDuration: movementDuration];
self.view.frame = CGRectOffset(self.view.frame, 0, movement);
[UIView commitAnimations];
}
- (IBAction)goingUp:(id)sender {
[self animateTextField:inputText up:TRUE];
}
#end

Answer 1

When you use insertRowsAtIndexPaths you have to first update the table view data source. So before you call the insertRowsAtIndexPaths you should do something like _messages addObject:newMessage.
Just as a helper rule, whenever you update the rows of a table view without using reloadData method, you have to update the tableView`s data source to reflect the index paths that will be updated. So if you delete on row from your table view, the data associated with that row must be deleted from data source, also if you add a row to the table view, you have to add the associated data of the new row into the data source. ALWAYS UPDATE THE DATASOURCE FIRST.
And every time you update the rows of a table view you should use the update method between beginUpdates and endUpdates method calls.

Answer 2

The problem was that I forgot to set
[tableView setDataSource:self];
[tableView setDelegate:self];
in my viewDidLoad. These two lines will fix my problem.