ios-how to save state of button after application close? - ios

Question

I struggle for few days and searched before.
I have button in UITableViewCell for favorite cell.
How to save state of button (selected button load image "fav.png" and normal button load "unfav.png") after application close?
// BirdsTableViewController.m
// iranbirdtest2
//
// Created by Mehdi on 9/27/15.
// Copyright (c) 2015 Mehdi.n13. All rights reserved.
// after 15 azar-21 mehr
#import "BirdsTableViewController.h"
#import "Bird.h"
#import "GeneralViewController.h"
#import "FavoriteTableViewController.h"
#import "MyManager.h"
//NSMutableArray *favoritesArray;
#interface BirdsTableViewController (){
}
#property (strong, nonatomic) UITabBarController *myTabbarController;
#property (strong, nonatomic) GeneralViewController *myFirstViewController;
#end
#implementation BirdsTableViewController
{
}
- (IBAction)buttonTouchDown:(UIButton *)sender {
sender.selected = !sender.selected; //to switch from selected to unselected
//OR in IBaction we can use:
/*
if ([sender isSelected]) {
[sender setImage:[UIImage imageNamed:#"unfav.png"] forState:UIControlStateNormal];
[sender setSelected:NO];
} else {
[sender setImage:[UIImage imageNamed:#"fav.png"] forState:UIControlStateSelected];
[sender setSelected:YES];
[[NSUserDefaults standardUserDefaults] setBool:YES forKey: #"someKey"];
}
*/
}
- (void) viewDidLoad {
[super viewDidLoad];
for (NSIndexPath *indexPath in [[NSUserDefaults standardUserDefaults] mutableArrayValueForKey:#"mySavedMutableArray"]) {
[self.tableView selectRowAtIndexPath:indexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
}
self.title=#"پرندگان ایران";
self.tableView.delegate = self;
self.tableView.dataSource = self;
//create array
birds=[[NSMutableArray alloc]init];
// UIButton* myButton;
Bird *bird=[[Bird alloc]init];
bird.name=#"زنبور خوار";
bird.filename=#"bird1";
bird.detail=#"این قسمت مربوط به توضیح می باشد";
[birds addObject:bird];
bird=[[Bird alloc]init]; //dont forget reuse
bird.name=#"زاغ";
bird.filename=#"bird2";
bird.detail=#"توضیحات مربوط به شماره ۲";
[birds addObject:bird];
bird=[[Bird alloc]init];
bird.name=#"طوطی";
bird.filename=#"bird3";
bird.detail=#"توضیحات مربوط به شماره سومی";
[birds addObject:bird];
//add more later
MyManager *sharedManager = [MyManager sharedManager];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
//this is for page view controller:
self.parentViewController.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"common_bg"]];
self.tableView.backgroundColor = [UIColor clearColor];
UIEdgeInsets inset = UIEdgeInsetsMake(5, 0, 0, 0);
self.tableView.contentInset = inset;
[self.tableView setSeparatorStyle:UITableViewCellSelectionStyleNone]; //delete sepreate line odf tables
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void) viewWillDisappear:(BOOL)animated{
}
#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 birds.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell" forIndexPath:indexPath];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
}
// Configure the cell...
tableView.allowsSelection=YES;
Bird *current=[birds objectAtIndex:indexPath.row];
UIImageView *birdImageView = (UIImageView *)[cell.contentView viewWithTag:100];
birdImageView.image = [UIImage imageNamed:current.filename];
UILabel *name = (UILabel *)[cell.contentView viewWithTag:101];
name.text=[current name];
//button code in table view
UIButton *button=(UIButton *) [cell.contentView viewWithTag:103];//fav
[button setImage:[UIImage imageNamed:#"unfav.png"] forState:UIControlStateNormal];
[button setImage:[UIImage imageNamed:#"fav.png"] forState:UIControlStateSelected];
button.frame = CGRectMake(0,0, 50, 50);
button.tag = indexPath.row;
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:button]; // add the button to the cell
[cell.contentView bringSubviewToFront:button];
// Assign our own background image for the cell
UIImage *background = [self cellBackgroundForRowAtIndexPath:indexPath];
UIImageView *cellBackgroundView = [[UIImageView alloc] initWithImage:background];
cellBackgroundView.image = background;
cell.backgroundView = cellBackgroundView;
UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"sepratortable.png"]];
[imgView sizeToFit];
[cell.contentView addSubview:imgView];
return cell;
}
-(void)buttonPressed:(UIButton *)sender
{
NSLog(#"Button Pressed");
MyManager *sharedManager = [MyManager sharedManager];
NSIndexPath *indexPath = [self.tableView indexPathForCell:(UITableViewCell*)sender.superview.superview];
if([sharedManager.favoritesArray containsObject:[birds objectAtIndex:indexPath.row]])
{
[sharedManager.favoritesArray removeObject:[birds objectAtIndex:indexPath.row]];
[self.tableView reloadData];
}
else
{
[sharedManager.favoritesArray addObject:[birds objectAtIndex:indexPath.row]];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Do you want to say hello?" message:#"More info..." delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Say Hello",nil];
[alert show];
; //we can remove later
}
//save favorite array in plist.
[NSKeyedArchiver archiveRootObject:sharedManager.favoritesArray toFile:#"/Users/Mehdi/Desktop/Project/Backup/21 mehr/fav.plist"];
NSLog(#"Favoritearray : %d",sharedManager.favoritesArray.count);
/*
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[userDefaults setValue:birds forKey:#"key"];
[[NSUserDefaults standardUserDefaults] synchronize];
*/
}
- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
{
}
- (UIImage *)cellBackgroundForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger rowCount = [self tableView:[self tableView] numberOfRowsInSection:0];
NSInteger rowIndex = indexPath.row;
UIImage *background = nil;
if (rowIndex == 0) {
background = [UIImage imageNamed:#"cell_top.png"];
} else if (rowIndex == rowCount - 1) {
background = [UIImage imageNamed:#"cell_bottom.png"];
} else {
background = [UIImage imageNamed:#"cell_middle.png"];
}
return background;
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark - Navigation
/*
In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
UITabBarController *pvc=[segue destinationViewController];
// Pass the selected object to the new view controller.
//what row selected?
NSIndexPath *path=[self.tableView indexPathForSelectedRow];
Bird *c =birds[path.row];
}
*/
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
/* if ([segue.identifier isEqualToString:#"ShowGeneralView"]) {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
GeneralViewController *destViewController = segue.destinationViewController;
destViewController.currentbird = [birds objectAtIndex:indexPath.row];
}
*/
self.myTabbarController = (UITabBarController*) [segue destinationViewController];
self.myFirstViewController = [self.myTabbarController.viewControllers objectAtIndex:0];
NSIndexPath *path=[self.tableView indexPathForSelectedRow];
Bird *c =birds[path.row];
_myFirstViewController.currentbird=c;
}
#end
I have no problem for save favorite row after application close.
Problem is with button state that can't save and retrieve.
I know I must use NSUserDefaults, but how?

Answer 1

It seems as though your favorites button is in a cell, and when the button is pressed, you add or remove the favorites from the birds array. You even seem to be storing the plist for a file for persistent storage between app launches. Unless I'm missing something, you need to set the state of the button in the cellForRowAtIndexPath when you build the row. Simply check the favorites array for the cell you are building and if it is in there, set the image to the correct state.
One thing to watch out for is that you need to set it regardless of what you think the default state for the image is. This is because cells are reused (for memory efficency). So let's say you build your cell with a default image state of a gray cell. The user clicks the favorite icon and you set it to the red heart. Then when the user scrolls the cell off the screen, iOS will reuse the cell and the image will still be set to the red image. If you don't explicitly set it to gray if the row is not in your favorites, it will stay red.
Also, as you allude to in your question, you could use NSUserDefaults to store your favorites array, rather than a file (and it would probably be simpler). It would also allow you to use iCloud to sync the user favorites across devices (with a bit more work to handle merge conflicts). There are plenty of resources for how to store data in NSUserDefaults.
In your cellForRowAtIndexPath, you would want to do something like the following:
if([sharedManager.favoritesArray containsObject:[birds objectAtIndex:indexPath.row]])
{
[button setSelected:NO];
} else {
[button setSelected:YES];
}
Also, in your buttonPressed method, you should be toggling the selected state of your button using
sender.selected = !sender.selected;
I would get rid of the (IBAction)buttonTouchDown: method and put all the button handling logic in the buttonPressed method. Having that logic in two places will cause confusion.