Question

我正在开发一个简单的iOS应用程序，其中有一些包含某些类别的表视图（CategoryViewController）。单击此类别之一时，视图将传递给RecipesListController，其中包含带有配方的另一个表视图。根据点击的类别，此配方从不同的plist加载。

我第一次点击某个类别时，会加载配方列表并正确显示。如果我回到类别列表并单击任何类别（也是相同的），应用程序崩溃。我不知道怎么做。 viewWillAppear在崩溃后得到了正确的判断。

你能帮帮我吗？如果您需要整个项目，我可以为您拉链。 OK？

这是CategoryViewController.h的代码

#import <Foundation/Foundation.h>
#import "RecipeRowViewController.h"

@class RecipesListController;

@interface CategoryViewController : UITableViewController {

    NSArray *recipeCategories;
    RecipesListController *childController;
}

@property (nonatomic, retain) NSArray *recipeCategories;

@end

CategoryViewControoler.m

#import "CategoryViewCotroller.h"
#import "NavAppDelegate.h"
#import "RecipesListController.h"


@implementation CategoryViewController

@synthesize recipeCategories; 



- (void)viewDidLoad {

    // Create the categories
    NSArray *array = [[NSArray alloc] initWithObjects:@"Antipasti", @"Focacce", @"Primi", @"Secondi", @"Contorni", @"Dolci", nil];
    self.recipeCategories = array;
    [array release];

    // Set background image
    UIImageView *bgImg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"sfondo_app.png"]];
    [self.tableView setBackgroundView:bgImg];
    [bgImg release];

    [self.tableView reloadData];
    [super viewDidLoad];
}



- (void)viewDidUnload {

    self.recipeCategories = nil;
//  [childController release];
    [super viewDidUnload];
}



- (void)dealloc {

    [recipeCategories release];
//  [childController release];
    [super dealloc];
}




#pragma mark -
#pragma mark Table data source methods

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

    return [recipeCategories count];
}



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellId = @"RecipesCategoriesCellId";

    // Try to reuse a cell or create a new one
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellId];
    if (cell == nil) {

        cell = [[[UITableViewCell alloc]
                 initWithStyle:UITableViewCellStyleDefault
                 reuseIdentifier:CellId] autorelease];
    }

    // Get the right value and assign to the cell
    NSUInteger row = [indexPath row];
    NSString *rowString = [recipeCategories objectAtIndex:row];
    cell.textLabel.text = rowString;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    [rowString release];

    return cell;
}



#pragma mark -
#pragma mark Table view delegate methods

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    if (childController == nil) {
        childController = [[RecipesListController alloc] initWithStyle:UITableViewStyleGrouped];
    }

    childController.title = @"Ricette";
    childController.category = [indexPath row];

    [self.navigationController pushViewController:childController animated:YES];
}



@end

RecipesListController.h

#import <Foundation/Foundation.h>
#import "RecipeRowViewController.h"

#define kRecipeArrayLink        0
#define kRecipeArrayDifficulty  1
#define kRecipeArrayFoodType    2


#define kRecipeAntipasti    0
#define kRecipeFocacce      1
#define kRecipePrimi        2
#define kRecipeSecondi      3
#define kRecipeContorni     4
#define kRecipeDolci        5


@class DisclosureDetailController;

@interface RecipesListController : UITableViewController {

    NSInteger category;
    NSDictionary *recipesArray;
    NSArray *recipesNames;
    NSArray *recipesLinks;
    DisclosureDetailController *childController;
}

@property (nonatomic) NSInteger category;
@property (nonatomic, retain) NSDictionary *recipesArray;
@property (nonatomic, retain) NSArray *recipesNames;
@property (nonatomic, retain) NSArray *recipesLinks;

@end

RecipesListcontroller.m

#import "RecipesListController.h"
#import "NavAppDelegate.h"
#import "DisclosureDetailController.h"


@implementation RecipesListController

@synthesize category, recipesArray, recipesNames, recipesLinks;



- (void)viewDidLoad {

    // Set background image
    UIImageView *bgImg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"sfondo_app.png"]];
    [self.tableView setBackgroundView:bgImg];
    [bgImg release];

    [self.tableView reloadData];

    [super viewDidLoad];
}



- (void)viewWillAppear:(BOOL)animated {

    if (self.recipesArray != nil) {

        // Release the arrays
        [self.recipesArray release];
        [self.recipesNames release];
    }

    // Load the dictionary
    NSString *path = nil;

    // Load a different dictionary, based on the category
    if (self.category == kRecipeAntipasti) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_antipasti" ofType:@"plist"];

    } else if (self.category == kRecipeFocacce) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_focacce" ofType:@"plist"];

    } else if (self.category == kRecipePrimi) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_primi" ofType:@"plist"];

    } else if (self.category == kRecipeSecondi) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_secondi" ofType:@"plist"];

    } else if (self.category == kRecipeContorni) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_contorni" ofType:@"plist"];

    } else if (self.category == kRecipeDolci) {
        path = [[NSBundle mainBundle] pathForResource:@"recipes_dolci" ofType:@"plist"];
    }

    NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:path];
    self.recipesArray = dict;
    [dict release];

    // Save recipes names
    NSArray *array = [[recipesArray allKeys] sortedArrayUsingSelector:
                      @selector(compare:)];
    self.recipesNames = array;

    [self.tableView reloadData];
    [super viewWillAppear:animated];
}


- (void)viewDidUnload {

    self.recipesArray = nil;
    self.recipesNames = nil;
    self.recipesLinks = nil;
//  [childController release];
    [super viewDidUnload];
}



- (void)dealloc {

    [recipesArray release];
    [recipesNames release];
    [recipesLinks release];
//  [childController release];
    [super dealloc];
}




#pragma mark -
#pragma mark Table data source methods

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

    return [recipesNames count];
}



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *RecipesListCellId = @"RecipesListCellId";

    // Try to reuse a cell or create a new one
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:RecipesListCellId];
    if (cell == nil) {

        cell = [[[UITableViewCell alloc]
                initWithStyle:UITableViewCellStyleDefault
                reuseIdentifier:RecipesListCellId] autorelease];
    }

    // Get the right value and assign to the cell
    NSUInteger row = [indexPath row];
    NSString *rowString = [recipesNames objectAtIndex:row];
    cell.textLabel.text = rowString;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    [rowString release];

    return cell;
}



#pragma mark -
#pragma mark Table view delegate methods

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    if (childController == nil) {
        childController = [[DisclosureDetailController alloc] initWithNibName:@"DisclosureDetail" bundle:nil];
    }

    childController.title = @"Dettagli";
    NSUInteger row = [indexPath row];

    childController.recipeName = [recipesNames objectAtIndex:row];

    NSArray *recipeRawArray = [recipesArray objectForKey:childController.recipeName];
    childController.recipeLink = [recipeRawArray objectAtIndex:kRecipeArrayLink];
    childController.recipeDifficulty = [recipeRawArray objectAtIndex:kRecipeArrayDifficulty];

    [self.navigationController pushViewController:childController animated:YES];
}



@end

这是崩溃日志

Program received signal:  “EXC_BAD_ACCESS”.
(gdb) bt
#0  0x00f0da63 in objc_msgSend ()
#1  0x04b27ca0 in ?? ()
#2  0x00002665 in -[RecipesListController viewWillAppear:] (self=0x4b38a00, _cmd=0x6d81a2, animated=1 '\001') at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:67
#3  0x00370c9a in -[UINavigationController _startTransition:fromViewController:toViewController:] ()
#4  0x0036b606 in -[UINavigationController _startDeferredTransitionIfNeeded] ()
#5  0x0037283e in -[UINavigationController pushViewController:transition:forceImmediate:] ()
#6  0x04f49549 in -[UINavigationControllerAccessibility(SafeCategory) pushViewController:transition:forceImmediate:] ()
#7  0x0036b4a0 in -[UINavigationController pushViewController:animated:] ()
#8  0x00003919 in -[CategoryViewController tableView:didSelectRowAtIndexPath:] (self=0x4b27ca0, _cmd=0x6d19e3, tableView=0x500c200, indexPath=0x4b2d650) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/CategoryViewCotroller.m:104
#9  0x0032a794 in -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] ()
#10 0x00320d50 in -[UITableView _userSelectRowAtPendingSelectionIndexPath:] ()
#11 0x000337f6 in __NSFireDelayedPerform ()
#12 0x00d8cfe3 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ ()
#13 0x00d8e594 in __CFRunLoopDoTimer ()
#14 0x00ceacc9 in __CFRunLoopRun ()
#15 0x00cea240 in CFRunLoopRunSpecific ()
#16 0x00cea161 in CFRunLoopRunInMode ()
#17 0x016e0268 in GSEventRunModal ()
#18 0x016e032d in GSEventRun ()
#19 0x002c342e in UIApplicationMain ()
#20 0x00001c08 in main (argc=1, argv=0xbfffef58) at /Users/claudiocanino/Documents/iOS/CottoMangiato/main.m:15

另一个bt日志：

(gdb) bt
#0  0x00cd76a1 in __CFBasicHashDeallocate ()
#1  0x00cc2bcb in _CFRelease ()
#2  0x00002dd6 in -[RecipesListController setRecipesArray:] (self=0x6834d50, _cmd=0x4293, _value=0x4e3bc70) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:16
#3  0x00002665 in -[RecipesListController viewWillAppear:] (self=0x6834d50, _cmd=0x6d81a2, animated=1 '\001') at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:67
#4  0x00370c9a in -[UINavigationController _startTransition:fromViewController:toViewController:] ()
#5  0x0036b606 in -[UINavigationController _startDeferredTransitionIfNeeded] ()
#6  0x0037283e in -[UINavigationController pushViewController:transition:forceImmediate:] ()
#7  0x091ac549 in -[UINavigationControllerAccessibility(SafeCategory) pushViewController:transition:forceImmediate:] ()
#8  0x0036b4a0 in -[UINavigationController pushViewController:animated:] ()
#9  0x00003919 in -[CategoryViewController tableView:didSelectRowAtIndexPath:] (self=0x4b12970, _cmd=0x6d19e3, tableView=0x5014400, indexPath=0x4b2bd00) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/CategoryViewCotroller.m:104
#10 0x0032a794 in -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] ()
#11 0x00320d50 in -[UITableView _userSelectRowAtPendingSelectionIndexPath:] ()
#12 0x000337f6 in __NSFireDelayedPerform ()
#13 0x00d8cfe3 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ ()
#14 0x00d8e594 in __CFRunLoopDoTimer ()
#15 0x00ceacc9 in __CFRunLoopRun ()
#16 0x00cea240 in CFRunLoopRunSpecific ()
#17 0x00cea161 in CFRunLoopRunInMode ()
#18 0x016e0268 in GSEventRunModal ()
#19 0x016e032d in GSEventRun ()
#20 0x002c342e in UIApplicationMain ()
#21 0x00001c08 in main (argc=1, argv=0xbfffef58) at /Users/claudiocanino/Documents/iOS/CottoMangiato/main.m:15

由于

Answer 1

// Get the right value and assign to the cell

NSUInteger row = [dexPath row]in;
NSString *rowString = [recipeCategories objectAtIndex:row];
cell.textLabel.text = rowString;
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

[rowString release];

我只是在寻找线索，因为我有一个非常类似的问题（我自己是一个初学者），但是当我查看你的代码时，你可能会释放rowstring，尽管你不拥有它？ [recipeCategories objectAtIndex:row]不应该让你对发布负责，不是创建/分配/复制方法。

iOS TableView崩溃加载不同的数据

1 个答案: