Question

i have just started learning objective C. want to create a small app where a login page should be there and password should be accepted only if its length is more than or equal to 8. once you submit that the next page should be a list of movies and in that page there should be a search button as well as add and remove buttons which can make that list editable. i created the login page and i have directly linked the submit button with the movie list page coz i was confused about how the condition of password length and username thing should be validated. kindly help me in doing that and to get the proper editing buttons for my movie list page.

Thanks

“ViewController.m”

#import "ViewController.h"
#import "MovieList.h"
@interface ViewController ()
@end
@implementation ViewController
-(void)loadView{
self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
self.view.backgroundColor = [UIColor cyanColor];
UILabel *name=[[UILabel alloc] init];
UILabel *pass=[[UILabel alloc] init];
UITextField *username = [[UITextField alloc]init];
UITextField *password = [[UITextField alloc]init];
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[name setBackgroundColor:[UIColor cyanColor]];
[name setText:@"UserID"];
[name setTextColor:[UIColor blackColor]];
[pass setBackgroundColor:[UIColor cyanColor]];
[pass setText:@"Password"];
[pass setTextColor:[UIColor blackColor]];
[button setTitle:@"SUBMIT" forState:UIControlStateNormal];
username.delegate = self;
password.delegate = self;
username.borderStyle = UITextBorderStyleRoundedRect;
password.borderStyle = UITextBorderStyleRoundedRect;
name.frame = CGRectMake(20, 15, 80, 20);
pass.frame = CGRectMake(15, 55, 80, 20);
username.frame = CGRectMake(100, 10, 200, 30);
password.frame = CGRectMake(100, 50, 200, 30);
button.frame = CGRectMake(130, 90, 80, 30);
[self.view addSubview:button];
[self.view addSubview:username];
[self.view addSubview:password];
[self.view addSubview:name];
[self.view addSubview:pass];
[button addTarget:self action:@selector(gotosecondpage)  forControlEvents:UIControlEventTouchUpInside];
}
-(void)gotosecondpage
{
Movielist *secondViewcont = [[Movielist alloc] init];
[self.navigationController pushViewController:secondViewcont animated:YES];
}
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:  (UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range   replacementString:(NSString *)string{
return YES;
}
- (BOOL)textFieldShouldClear:(UITextField *)textField{
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
[textField resignFirstResponder];
return YES;
}
@end

“MovieList.m”

#import "MovieList.h"
@interface Movielist()
@end
@implementation Movielist
-(void)loadView{
self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
self.view.backgroundColor = [UIColor cyanColor];
}
-(id)init{
[self.navigationItem setTitle:@"Movie List"];
return self;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    [self.view setBackgroundColor:[UIColor cyanColor]];
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect frame = self.view.frame;
UITableView *tableView = [[UITableView alloc] initWithFrame:frame   style:UITableViewStylePlain];

tableView.separatorStyle = UITableViewCellSeparatorStyleSingleLine;
tableView.backgroundColor = [UIColor cyanColor];
tableView.delegate = self;
tableView.dataSource = self;
[self.view addSubview:tableView];
[tableView setScrollEnabled:YES];
[tableView setUserInteractionEnabled:YES];
[tableView setRowHeight:35];
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cellIDent"];
char ch = 'a' + indexPath.row;
cell.textLabel.text = [NSString stringWithFormat:@"%c" , ch];
    return cell;
}
@end

Answer 1

Checking length is very straight. The important thing is how do you navigate from login page. Currently I see gotosecondpage function is responsible. You can probably write a validateParams method, under which you can call gotosecondpage if all conditions are met.

This code will tell you about password length:

-(void) validateParams 
{
    NSString * password = [password text];
    if ([password length] < 8) //and maybe other conditions, too
    {
       [self gotosecondpage];
    }    
    else
    {
       //report error - maybe show some UILabel near username / password fields to show which one of them went wrong
    }
}

Note that there are many other things you can do – like telling the user which field needs correction, and there are many better ways. Since your requirements are quite basic, above should help for now.