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iOS

Posted by Elizabeth Hill
Elizabeth Hill
1,147 Points

Ribbit friends

Ok so I have a couple problems with the ribbit app. http://teamtreehouse.com/library/build-a-selfdestructing-message-iphone-app-2/relating-users-in-parsecom/adding-checkmarks-when-the-table-view-is-loaded-2

1.The app won't show checkmarks in the edit friends page and the friends won't show up in the friends page.

  1. I don't really understand how the app will crash if you loop through friends so is there a way to fix that?

  2. Is there any way to create another UITableViewController that shows friends that are following you?

4 Answers

Brenden Konnagan
Brenden Konnagan
16,858 Points
Brenden Konnagan
Brenden Konnagan
16,858 Points

Hello Martha!

I will try my best to help... :-)

  1. can you post a code snippet? that may help in answering your question.

  2. can you provide some context to this question? I am not sure that I am understanding your issue.

  3. there is of course a way to do that... :-) which part are you unsure of?

Elizabeth Hill
Elizabeth Hill
1,147 Points

I apologize if the code is not written right on the forum. I read the code cheat sheet and it is not working.

here is the code. I know this is a lot but its edit friends view controller and friends view controller. The checkmark won't show up in the edit friends view controller and the friends won't show up in the friends view controller. When I mean the app will crash is when Ben says in the beginning of the video that its easier to loop through friends but he prefers hashing and caching.

edit friends view controller.h

``` Objective C

import <UIKit/UIKit.h>

@interface EditfriendsViewController : UITableViewController @property (nonatomic, strong) NSArray *allUsers; @property (nonatomic, strong) PFUser *currentUser; @property (nonatomic, strong) NSMutableArray *friends;

  • (BOOL)isFriend:(PFUser *)user; @end ``` edit friends view controller.m

import "EditfriendsViewController.h"

@interface EditfriendsViewController ()

@end

@implementation EditfriendsViewController

  • (void)viewDidLoad { [super viewDidLoad]; PFQuery *query = [PFUser query]; [query orderByAscending:@"username"]; [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) { if (error) { NSLog(@"Error: %@ %@", error, [error userInfo]); } else { self.allUsers = objects; [self.tableView reloadData];

    }

    }];

    self.currentUser = [PFUser currentUser];

}

pragma mark - Table view data source

  • (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    // Return the number of sections. return 1; }

  • (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    // Return the number of rows in the section. return [self.allUsers count]; }

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

    PFUser *user = [self.allUsers objectAtIndex:indexPath.row]; cell.textLabel.text = user.username;

    //APP CRASH through looping if ([self isFriend:user]) { //add checkmark cell.accessoryType = UITableViewCellAccessoryCheckmark;

    } else { //clear checkmark cell.accessoryType = UITableViewCellAccessoryNone; }

    return cell; }

pragma mark - Table view delegate

  • (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath { [self.tableView deselectRowAtIndexPath:indexPath animated:NO];

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; cell.accessoryType = UITableViewCellAccessoryCheckmark; PFRelation *friendsRelation = [self.currentUser relationForKey:@"friendsRelation"]; PFUser *user = [self.allUsers objectAtIndex:indexPath.row];

    if ([self isFriend:user]) { cell.accessoryView = nil;

    for(PFUser *friend in self.friends) {
    if ([friend.objectId isEqualToString:user.objectId]) {
        [self.friends removeObject:friend];
        break;
    }
}
[friendsRelation removeObject:user];

    } else { cell.accessoryView = UITableViewCellAccessoryNone; [self.friends addObject:user]; [friendsRelation addObject:user]; } [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) { if (error) { NSLog(@"Error: %@ %@", error, [error userInfo]); } }]; }

pragma mark - Helper methods

//app will crash while looping

  • (BOOL)isFriend:(PFUser *)user { for (PFUser *friend in self.friends) { if ([friend.objectId isEqualToString:user.objectId]) { return YES; } }

    return NO;

}

@end

friends view controller.h

import <UIKit/UIKit.h>

import <Parse/Parse.h>

@interface friendsViewController : UITableViewController

@property (nonatomic, strong) PFRelation *friendsRelation; @property (nonatomic, strong) NSArray *friends;

@end

friends view controller.m

import "friendsViewController.h"

import "GravatarUrlBuilder.h"

import "EditfriendsViewController.h"

@interface friendsViewController ()

@end

@implementation friendsViewController

  • (void)viewDidLoad { [super viewDidLoad];

}

  • (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated];

    self.friendsRelation = [[PFUser currentUser] objectForKey:@"friendsRelation"];

    PFQuery *query = [self.friendsRelation query]; [query orderByAscending:@"username"]; [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) { if (error) { NSLog(@"Error %@ %@", error, [error userInfo]); } else { self.friends = objects; [self.tableView reloadData];

    }

    }];

} //APP CRASH VIDEO

  • (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { if ([segue.identifier isEqualToString:@"showEditFriends"]) { EditfriendsViewController *viewController = (EditfriendsViewController *)segue.destinationViewController; viewController.friends = [NSMutableArray arrayWithArray:self.friends];

    } }

pragma mark - Table view data source

  • (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    // Return the number of sections. return 1; }

  • (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    // Return the number of rows in the section. return [self.friends count]; }

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

    PFUser *user = [self.friends objectAtIndex:indexPath.row]; cell.textLabel.text = user.username;

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(queue, ^{ //get email address NSString *email = [user relationForKey:@"email"];

    //create md5 hash
NSURL *gravatarUrl = [GravatarUrlBuilder getGravatarUrl:email];

//request image from gravatar
NSData *imageData = [NSData dataWithContentsOfURL:gravatarUrl];

dispatch_async(dispatch_get_main_queue(), ^{ //set image in cell
    cell.imageView.image = [UIImage imageWithData:imageData];
    [cell setNeedsLayout];

    });

    });

    return cell; }

@end

Patrick Serrano
Patrick Serrano
13,834 Points
Patrick Serrano
Patrick Serrano
13,834 Points

It would be helpful if you posted the relevant code so we can try to spot where the problem you are having it. Be sure to format the code as code using markdown. (There is a handily link to the Markdown Cheatsheet below the textfield where you enter your post if you're unfamiliar with Markdown)

Elizabeth Hill
Elizabeth Hill
1,147 Points

here is the code. I know this is a lot but its edit friends view controller and friends view controller. The checkmark won't show up in the edit friends view controller and the friends won't show up in the friends view controller. When I mean the app will crash is when Ben says in the beginning of the video that its easier to loop through friends but he prefers hashing and caching.

edit friends view controller.h

#import <UIKit/UIKit.h>
#import <Parse/Parse.h>

@interface EditfriendsViewController : UITableViewController

@property (nonatomic, strong) NSArray *allUsers;
@property (nonatomic, strong) PFUser *currentUser;
@property (nonatomic, strong) NSMutableArray *friends;

- (BOOL)isFriend:(PFUser *)user;

@end

edit friends view controller.m

#import "EditfriendsViewController.h"

@interface EditfriendsViewController ()

@end

@implementation EditfriendsViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    PFQuery *query = [PFUser query];
    [query orderByAscending:@"username"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
        else {
            self.allUsers = objects;
            [self.tableView reloadData];

      }

    }];

    self.currentUser = [PFUser currentUser];
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{

    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    // Return the number of rows in the section.
    return [self.allUsers count];
}

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

    PFUser *user = [self.allUsers objectAtIndex:indexPath.row];
    cell.textLabel.text = user.username;


    //APP CRASH through looping
    if ([self isFriend:user]) {
        //add checkmark
        cell.accessoryType = UITableViewCellAccessoryCheckmark;

    }
    else {
        //clear checkmark
        cell.accessoryType = UITableViewCellAccessoryNone;
    }

    return cell;
}

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath {
    [self.tableView deselectRowAtIndexPath:indexPath animated:NO];

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    cell.accessoryType = UITableViewCellAccessoryCheckmark;
    PFRelation *friendsRelation = [self.currentUser relationForKey:@"friendsRelation"];
    PFUser *user = [self.allUsers objectAtIndex:indexPath.row];

    if ([self isFriend:user]) {
        cell.accessoryView = nil;

        for(PFUser *friend in self.friends) {
            if ([friend.objectId isEqualToString:user.objectId]) {
                [self.friends removeObject:friend];
                break;
            }
        }
        [friendsRelation removeObject:user];
    }
         else {
             cell.accessoryView = UITableViewCellAccessoryNone;
             [self.friends addObject:user];
             [friendsRelation addObject:user];
         }
         [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (error) {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];
         }

    #pragma mark - Helper methods


//app will crash while looping
- (BOOL)isFriend:(PFUser *)user {
    for (PFUser *friend in self.friends) {
        if ([friend.objectId isEqualToString:user.objectId]) {
            return YES;
        }
    }

    return NO;

}

@end

friends view controller.h

#import <UIKit/UIKit.h>
#import <Parse/Parse.h>

@interface friendsViewController : UITableViewController

@property (nonatomic, strong) PFRelation *friendsRelation;
@property (nonatomic, strong) NSArray *friends;

@end

friends view controller.m

#import "friendsViewController.h"
#import "GravatarUrlBuilder.h"
#import "EditfriendsViewController.h"

@interface friendsViewController ()

@end

@implementation friendsViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

}

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

    self.friendsRelation = [[PFUser currentUser] objectForKey:@"friendsRelation"];

    PFQuery *query = [self.friendsRelation query];
    [query orderByAscending:@"username"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
        else {
            self.friends = objects;
            [self.tableView reloadData];

        }

    }];

    }
//APP CRASH VIDEO
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([segue.identifier isEqualToString:@"showEditFriends"]) {
        EditfriendsViewController *viewController = (EditfriendsViewController *)segue.destinationViewController;
        viewController.friends = [NSMutableArray arrayWithArray:self.friends];

           }
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
 // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    // Return the number of rows in the section.
    return [self.friends count];
}

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

    PFUser *user = [self.friends objectAtIndex:indexPath.row];
    cell.textLabel.text = user.username;

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(queue, ^{
        //get email address
        NSString *email = [user relationForKey:@"email"];

        //create md5 hash
        NSURL *gravatarUrl = [GravatarUrlBuilder getGravatarUrl:email];

        //request image from gravatar
        NSData *imageData = [NSData dataWithContentsOfURL:gravatarUrl];

        dispatch_async(dispatch_get_main_queue(), ^{ //set image in cell
            cell.imageView.image = [UIImage imageWithData:imageData];
            [cell setNeedsLayout];
     });

    });

     return cell;
}

@end
Elizabeth Hill
Elizabeth Hill
1,147 Points
Elizabeth Hill
Elizabeth Hill
1,147 Points

this is frustrating

chitra iyer
chitra iyer
3,722 Points
chitra iyer
chitra iyer
3,722 Points

Regrading your first problem - no checkmarks in the edit friends page - did you implement the didSelectRowAtIndexPath method in EditFriends?

In the accessoryButtonTappedForRowWithIndexPath method that you have implemented, in the else block - where you validate if user is a friend, you have the following line of code

```cell.accessoryView = UITableViewCellAccessoryNone;