I have two different view controllers displaying almost the same fetch request. One of them displays more info than the other and is also used for editing of the data. The second one is just for display.
Is there a way to speed things up, since both are displaying exactly the same data? I'm looking for something in my code which makes the whole reorder slow after displaying the second view controller for the first time. In other words: Initially the reordering in my main view controller is very fast. Then you just display the second view controller and switch back and then the reordering in the main view controller gets slow. I have reason to assume that it is because they are using the same fetch.
I'm initiating the fetch request in both viewDidLoad methods, as in the following code snippets. The first one is my main view controller, and also the first one displayed when starting the app:
- (void)setupFetchedResultsController
{
self.managedObjectContext = ((AppDelegate *)[[UIApplication sharedApplication] delegate]).managedObjectContext;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"MainCategory"];
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"position" ascending:YES]];
self.fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:request
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:nil cacheName:@"MainCategoryCache"];
}
And this is my second one:
- (void)setupFetchedResultsController
{
self.managedObjectContext = ((AppDelegate *)[[UIApplication sharedApplication] delegate]).managedObjectContext;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"MainCategory"];
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"position" ascending:YES]];
self.fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:request
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:nil
cacheName:@"NetCache"];
}
Here are the view did load and cellForRowAtIndexPath of my main view controller:
- (void)viewDidLoad
{
[super viewDidLoad];
[self setupFetchedResultsController];
//Edit/Done button
UIBarButtonItem *editButton = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Edit", nil) style:UIBarButtonItemStyleBordered target:self action:@selector(editTable:)];
[self.navigationItem setRightBarButtonItem:editButton];
//Budget at bottom
self.sumTitleLabel.text = [NSString stringWithFormat:@"%@%@:",NSLocalizedString(@"Budget", nil),NSLocalizedString(@"PerMonth", nil)];
self.sumLabel.text = [[DatabaseFetches budgetPerMonthForManagedObjectContext:self.managedObjectContext] getLocalizedCurrencyString];
//Layout
self.view.backgroundColor = [UIColor clearColor];
[self styleTableView];
[self styleBudgetTotal];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//Data model and cell setup
static NSString *CellIdentifier = @"MainCategoryCell";
MainCategoryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
MainCategory *mainCategory = [self.fetchedResultsController objectAtIndexPath:indexPath];
//Clear background color
cell.backgroundColor = [UIColor clearColor];
//Setup the cell texts
cell.title.text = mainCategory.name;
int numberOfSubcategories = [[mainCategory getNumberOfSpendingCategories] integerValue];
if (numberOfSubcategories == 1) {
cell.subcategories.text = [NSString stringWithFormat:@"%i %@", numberOfSubcategories, NSLocalizedString(@"subcategory", nil)];
} else {
cell.subcategories.text = [NSString stringWithFormat:@"%i %@", numberOfSubcategories, NSLocalizedString(@"subcategories", nil)];
}
cell.costs.text = [[mainCategory getMonthlyCostsOfAllSpendingCategories] getLocalizedCurrencyString];
//Delegation
cell.title.delegate = self;
//Format text
cell.title.font = [Theme tableCellTitleFont];
cell.title.textColor = [Theme tableCellTitleColor];
cell.title.tag = indexPath.row;
cell.subcategories.font = [Theme tableCellSubTitleFont];
cell.subcategories.textColor = [Theme tableCellSubTitleColor];
cell.costs.font = [Theme tableCellValueFont];
cell.costs.textColor = [Theme tableCellValueColor];
//Icon
UIImage *icon;
if(!mainCategory.icon){
icon = [UIImage imageNamed:@"DefaultIcon.png"];
} else {
icon = [UIImage imageNamed:mainCategory.icon];
}
[cell.iconButton setImage:icon forState: UIControlStateNormal];
cell.icon.image = icon;
cell.iconButton.tag = indexPath.row;
//Background image
cell.cellBackground.image = [[UIImage imageNamed:@"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
//Selection
//cell.title.highlightedTextColor = cell.title.textColor;
cell.subcategories.highlightedTextColor = cell.subcategories.textColor;
cell.costs.highlightedTextColor = cell.costs.textColor;
return cell;
}
Complete second view controller:
@interface NetIncomeViewController()
@property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;
@end
@implementation NetIncomeViewController
@synthesize incomeTitleLabel = _incomeTitleLabel;
@synthesize incomeValueTextField = _incomeValueTextField;
@synthesize incomeBackground = _incomeBackground;
@synthesize incomeValueBackground = _incomeValueBackground;
@synthesize netIncomeTitleLabel = _netIncomeTitleLabel;
@synthesize netIncomeValueLabel = _netIncomeValueLabel;
@synthesize netIncomeBackground = _netIncomeBackground;
@synthesize netIncomeValueBackground = _netIncomeValueBackground;
@synthesize managedObjectContext = _managedObjectContext;
#pragma mark Initializer and view setup
- (void)setupFetchedResultsController
{
self.managedObjectContext = ((AppDelegate *)[[UIApplication sharedApplication] delegate]).managedObjectContext;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"MainCategory"];
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"position" ascending:YES]];
self.fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:request
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:nil
cacheName:nil];
}
#pragma mark View lifecycle
- (void)awakeFromNib{
[super awakeFromNib];
//Title (necessary here because otherwise the tab bar would be only localized after first click
//on the respective tab bar and not from beginning
self.title = NSLocalizedString(@"Net Income", nil);
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self updateNetIncome];
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self setupFetchedResultsController];
//Edit/Done button
UIBarButtonItem *editButton = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Edit", nil) style:UIBarButtonItemStyleBordered target:self action:@selector(editIncome:)];
[self.navigationItem setRightBarButtonItem:editButton];
//Get or set and get the gross income
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSNumber *grossIncome = [defaults objectForKey:@"income"];
if (!grossIncome) {
[defaults setDouble:0 forKey:@"income"];
[defaults synchronize];
grossIncome = [defaults objectForKey:@"income"];
}
self.incomeValueTextField.enabled = NO;
self.incomeValueTextField.delegate = self;
self.incomeValueTextField.keyboardType = UIKeyboardTypeDecimalPad;
self.incomeValueTextField.text = [grossIncome getLocalizedCurrencyString];
[self styleTableViewAndIncome];
}
- (void)styleTableViewAndIncome
{
self.view.backgroundColor = [UIColor clearColor];
self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
self.tableView.backgroundColor = [UIColor clearColor];
self.incomeTitleLabel.textColor = [Theme budgetValueTitleColor];
self.incomeTitleLabel.font = [Theme budgetValueTitleFont];
self.incomeValueTextField.textColor = [Theme budgetValueColor];
self.incomeValueTextField.font = [Theme budgetValueTitleFont];
self.netIncomeTitleLabel.textColor = [Theme budgetValueTitleColor];
self.netIncomeTitleLabel.font = [Theme budgetValueTitleFont];
self.netIncomeValueLabel.textColor = [Theme budgetValueColor];
self.netIncomeValueLabel.font = [Theme budgetValueFont];
self.incomeTitleLabel.text = [NSString stringWithFormat:@"%@:",NSLocalizedString(@"Income", nil)];
self.netIncomeTitleLabel.text = [NSString stringWithFormat:@"%@%@:",NSLocalizedString(@"Net", nil),NSLocalizedString(@"PerMonth", nil)];
self.incomeBackground.image = [[UIImage imageNamed:@"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
self.incomeValueBackground.image = [[UIImage imageNamed:@"price-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
self.netIncomeBackground.image = [[UIImage imageNamed:@"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
}
#pragma mark Table view delegate methods
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"CategoryCostCell";
CategoryCostTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor clearColor];
// Configure the cell layout
MainCategory *mainCategory = [self.fetchedResultsController objectAtIndexPath:indexPath];
// Configure the cell layout
cell.categoryBackground.image = [[UIImage imageNamed:@"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
if(!mainCategory.icon){
cell.categoryImage.image = [UIImage imageNamed:@"DefaultIcon.png"];
} else {
cell.categoryImage.image = [UIImage imageNamed:mainCategory.icon];
}
cell.categoryName.text = mainCategory.name;
NSNumber *expenditures = [mainCategory getMonthlyCostsOfAllSpendingCategories];
double expendituresDouble =-[expenditures doubleValue];
if (expendituresDouble == 0) {
expenditures = [NSNumber numberWithDouble: 0];
} else {
expenditures = [NSNumber numberWithDouble: expendituresDouble];
}
cell.categoryCosts.text = [expenditures getLocalizedCurrencyString];
//Format the text
cell.categoryName.font = [Theme tableCellSmallTitleFont];
cell.categoryName.textColor = [Theme tableCellSmallTitleColor];
cell.categoryCosts.font = [Theme tableCellSmallValueFont];
cell.categoryCosts.textColor = [Theme tableCellSmallValueColor];
return cell;
}
#pragma mark TextField delegate methods
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
if(self.editing){
return YES;
} else {
return NO;
}
}
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
textField.text = [NSString stringWithFormat:@"%.2f",[NSNumber getUnLocalizedCurrencyDoubleWithString:textField.text]];
}
-(void)textFieldDidEndEditing:(UITextField *)textField
{
textField.text = [[NSNumber numberWithDouble:[textField.text doubleValue]] getLocalizedCurrencyString];
}
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
//Handle the enter button
[textField resignFirstResponder];
[self endEdit];
//Since this method is called AFTER DidEndEditing, we have to call editTable or in this case since we have put all the endEdit code in a seperate method this method directly in order to format the table back from edit mode to normal.
return YES;
}
#pragma mark Edit/Add/Delete action
- (IBAction) editIncome:(id)sender
{
if(self.editing)
{
[self endEdit];
} else {
[self beginEdit];
}
}
- (void) beginEdit
{
//Change to editing mode
[super setEditing:YES animated:YES];
//Exchange the edit button with done button
[self.navigationItem.rightBarButtonItem setTitle:NSLocalizedString(@"Done", nil)];
[self.navigationItem.rightBarButtonItem setStyle:UIBarButtonItemStyleDone];
self.incomeValueTextField.borderStyle = UITextBorderStyleRoundedRect;
self.incomeValueTextField.enabled = YES;
self.incomeValueBackground.hidden = YES;
self.incomeValueTextField.textColor = [Theme budgetValueTitleColor];
}
- (void) endEdit
{
//Change to editing no
[super setEditing:NO animated:YES];
//Remove Done button and exchange it with edit button
[self.navigationItem.rightBarButtonItem setTitle:NSLocalizedString(@"Edit", nil)];
[self.navigationItem.rightBarButtonItem setStyle:UIBarButtonItemStylePlain];
self.incomeValueTextField.borderStyle = UITextBorderStyleNone;
self.incomeValueTextField.enabled = NO;
self.incomeValueBackground.hidden = NO;
self.incomeValueTextField.textColor = [Theme budgetValueColor];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setDouble:[NSNumber getUnLocalizedCurrencyDoubleWithString:self.incomeValueTextField.text] forKey:@"income"];
[self updateNetIncome];
//[defaults synchronize];
}
#pragma mark Net income
- (void) updateNetIncome {
double grossIncome = [NSNumber getUnLocalizedCurrencyDoubleWithString:self.incomeValueTextField.text];
double budget = [[DatabaseFetches budgetPerMonthForManagedObjectContext:self.managedObjectContext] doubleValue];
double netIncome = grossIncome - budget;
if(netIncome >0){
self.netIncomeValueBackground.image = [[UIImage imageNamed:@"price-bkg_green"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
} else if(netIncome <0) {
self.netIncomeValueBackground.image = [[UIImage imageNamed:@"price-bkg_red"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
} else {
self.netIncomeValueBackground.image = [[UIImage imageNamed:@"price-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
}
self.netIncomeValueLabel.text = [[NSNumber numberWithDouble:netIncome] getLocalizedCurrencyString];
}
@end
It looks like you're doing UIImage creation in your cellForRowAtIndexPath method, which would cause a slowdown.
Better to create the background UIImage as an instance variables and set its image in the viewDidLoad, then reference it in the cellForRowAtIndexPath method. Like so:
//Declare the instance variable
UIImage *backgroundImage
//Set it in viewDidLoad
self.backgroundImage = [[UIImage imageNamed:@"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
//Assign it in cellForRowAtIndexPath
cell.backgroundImage = self.backgroundImage;
As for the icon, which has to be set for each row, you'll want to move the actual image loading off the main thread. You can do this either with dispatch_async() or NSOperationQueue. (pulled from here: Understanding dispatch_async)
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
UIImage *icon;
if(!mainCategory.icon){
icon = [UIImage imageNamed:@"DefaultIcon.png"];
} else {
icon = [UIImage imageNamed:mainCategory.icon];
}
dispatch_async(dispatch_get_main_queue(), ^(void){
[cell.iconButton setImage:icon forState: UIControlStateNormal];
cell.icon.image = icon;
cell.iconButton.tag = indexPath.row;
});
});
Notice how the imageNamed method is called in the background thread, but the actual assignment takes place on the main thread. You have to do it this way because you're not allowed to update UI elements anywhere except the main thread.