Question

我有一个tableView:didSelectRowAtIndexPath:，每次选择一个项目时我都会创建一个ViewController-Instance。有时它很长时间都能正常工作，有时会很快崩溃EXC_BAD_ACCESS。调试器会在QuestionDetailViewController中归咎于行[super dealloc];。

为什么呢？我记录了QuestionDetailViewController的retainCount。看起来很好。

QuestionDetailViewController

#import <UIKit/UIKit.h>
#import "Question.h"
#import "Answer.h"
@interface QuestionDetailViewController : UIViewController < UIScrollViewDelegate , QuestionDetailViewProtocol> {
    Question *question;
    UILabel *answerText;
    UILabel *titleLabel;
}

@property(nonatomic,retain) Question *question;
@property(nonatomic,retain) UILabel *answerText;
@property(nonatomic,retain) UILabel *titleLabel;

@end


#import "QuestionDetailViewController.h"
@implementation QuestionDetailViewController
@synthesize question;
@synthesize answerText;
@synthesize titleLabel; 


- (void)viewDidLoad {
    [super viewDidLoad];
}

- (void)viewWillAppear:(BOOL)animated {
    UIColor *bgColor = [UIColor colorWithRed:199.0/255 green:234.0/255 blue:251.0/255 alpha:1];
    self.answerText = (UILabel *)[self.view viewWithTag:2]; 
    self.answerText.backgroundColor = bgColor;
    self.answerText.text = self.question.answer.text;
    self.titleLabel = (UILabel*)[self.view viewWithTag:1]; 
    CGSize sizeTitle = [self.question.title sizeWithFont:[titleLabel font]
                                       constrainedToSize:CGSizeMake(280.0, INFINITY) 
                                           lineBreakMode:UILineBreakModeWordWrap];
    self.titleLabel.text = self.question.title;
    self.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
    self.titleLabel.frame = CGRectMake(10,10, 260, sizeTitle.height);

    CGSize sizeText = [self.question.answer.text sizeWithFont:[self.answerText font]
                                            constrainedToSize:CGSizeMake(280.0, INFINITY) 
                                                lineBreakMode:UILineBreakModeWordWrap];
    self.answerText.frame = CGRectMake(0,20+sizeTitle.height, 310, sizeText.height+sizeTitle.height);
    [(UIScrollView *)self.view setContentSize:CGSizeMake(280, answerText.frame.size.height +sizeTitle.height)];
    self.view.backgroundColor = bgColor;
    [super viewWillAppear:animated];
}

- (void)viewDidDisappear:(BOOL)animated {
    NSLog(@"%d", [self retainCount]);
    [super viewDidDisappear:animated];
    [self release];
}

-(IBAction)goBack:(id)sender{
    [self.navigationController popViewControllerAnimated:YES];
}

- (void)dealloc {
    NSLog(@"QDC dealoc");
    [self.answerText release];
    [self.titleLabel release];
    [self.question release];
    [super dealloc];
}

@end

的tableView：didSelectRowAtIndexPath方法：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {   
    QuestionDetailViewController *qdc = [[QuestionDetailViewController alloc] initWithNibName:@"QuestionDetailViewController" bundle:nil];
    Question* question;
    if ([filteredQuestions count]>0) {
        question = [self.filteredQuestions objectAtIndex:indexPath.row];
    } else {
        question = [self.questions objectAtIndex:indexPath.row];
    }
    [qdc setQuestion:question];
    [question release];
    NSLog(@"%d", [qdc retainCount]);
    [self.navigationController pushViewController:qdc animated:YES];
    [qdc release];
}

Answer 1

而不是：

[self.answerText release];
[self.titleLabel release];
[self.question release];

使用：

self.answerText = nil;
self.titleLabel = nil;
self.question = nil;

或：

[answerText release]; answerText = nil;
[titleLabel release]; titleLabel = nil;
[question release]; question = nil;

Answer 2

此：

- (void)viewDidDisappear:(BOOL)animated {
    NSLog(@"%d", [self retainCount]);
    [super viewDidDisappear:animated];
    [self release];
}

看起来非常可疑。你做过[self retain]吗？如果没有，那么你为什么要发布？如果你是，你可能做错了什么，因为[self retain]是需要做的非常罕见的事情。

弹出视图在[super dealloc]崩溃应用程序

2 个答案: