App is crashing when NSMutableArray no Objects in iOS

Question

I have four textfields like textfield1, textfield2, textfield3, textfield4 and one button. When I click on the button I am adding the textfield text to an NSMutableArray and populating in a tableview.

My code is:

- (void)buttonClick
{
    NSMutableArray  *array =[[NSMutableArray alloc]init];
    [array addObject: textfield1.text];
    [array addObject: textfield2.text];
    [array addObject: textfield3.text];
    [array addObject: textfield4.text];
 }

Populating in table view using delegate methods

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [array count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }

    cell.textLabel.text =[array objectAtIndex:indexPath.row];
    return cell;
}

The above code is working fine. But when I click on button without entering any data in the textfields, the app is crashing because the array is empty. How to solve this problem?

Nikolai Ruhe · Accepted Answer · 2014-03-05 10:48:51Z

3

You can't add nil to an array.

[array addObject:textfield1.text ?: @""];
[array addObject:textfield2.text ?: @""];
[array addObject:textfield3.text ?: @""];
[array addObject:textfield4.text ?: @""];

This makes sure there are four items in the array (possibly empty strings).

answered Mar 5, 2014 at 10:48

Nikolai Ruhe

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Comments

Vijay-Apple-Dev.blogspot.com · Accepted Answer · 2014-03-05 10:48:22Z

1

Why crashes?

You can't add nil in array. It should have something inside of it.

-(void)buttonClick
{
    NSMutableArray  *array =[[NSMutableArray alloc]init];

    if ([textfield1.text length]>0) {
        [array addObject: textfield1.text];

    }
    if ([textfield2.text length]>0) {
        [array addObject: textfield2.text];

    }
    if ([textfield3.text length]>0) {
        [array addObject: textfield3.text];
    }



}

answered Mar 5, 2014 at 10:48

Vijay-Apple-Dev.blogspot.com

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Comments

Satish Azad · Accepted Answer · 2014-03-05 10:57:17Z

0

Try this

-(void)buttonClick
{
    NSMutableArray  *array =[[NSMutableArray alloc]init];
     if(textfield1.text.length > 0)
        [array addObject: textfield1.text];

     if(textfield2.text.length > 0)
        [array addObject: textfield2.text];

     if(textfield3.text.length > 0)
        [array addObject: textfield3.text];

    if(textfield4.text.length > 0)
        [array addObject: textfield4.text];

 }

Populating in table view using delegate methods

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [array count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }
    cell.textLabel.text =[array objectAtIndex:indexPath.row];
    return cell;
}

if you have multiple text fields then: //give tag value of each textfield from 100 to 150 or any any tag (i am considering 50 text fields)

for (int i=100; i<=150; i++) {
// self.view or use ur view on which u r addding textfield
    id txtF = [self.view viewWithTag:i]; 
    if([txtF isKindOfClass:[UITextField class]]) {
        UITextField *txtField = (UITextField*)txtF;
        if(txtField.text.length > 0) {
            //Add ur object
        }
    }
}

edited Mar 5, 2014 at 10:57

answered Mar 5, 2014 at 10:48

Satish Azad

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3 Comments

user3373798 Over a year ago

Thank you for your quick response. I have one dought suppose if i have more textfield suppose 20 textfield. I have to check 20 conditions like if (textfiled.text.length>0). Is there any alternative solution for this. Please tell me

user3373798 Over a year ago

k I will implement and let you know

Satish Azad Over a year ago

also make sure that there is no other subview on view whose tag value is lying in between the range of ur textfields tag. its better to take range of tags for textfields more tha 1000 or 3000 etc

Harsh Thakur · Accepted Answer · 2014-03-05 10:49:49Z

0

you can check the textfields before putting an array wheather it has text or not if yes then put in the array only.

answered Mar 5, 2014 at 10:49

Harsh Thakur

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Comments

EmilyJ · Accepted Answer · 2014-03-05 11:04:31Z

0

This line in the buttonClick method defined a local array variable:

NSMutableArray  *array =[[NSMutableArray alloc]init];

It should be

array =[[NSMutableArray alloc]init];

Which is your instance variable array.

answered Mar 5, 2014 at 11:04

EmilyJ

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