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在[super dealloc]弹出视图崩溃应用程序

retain release objective-c iphone

vikingosegundo · 技术社区 · 15 年前

我有一个 tableView:didSelectRowAtIndexPath: 在这里,我每次选择一个项目时都创建一个viewcontroller实例。有时它可以工作很长时间,有时它崩溃与 EXC_BAD_ACCESS 很快。调试程序将此行归咎于 [super dealloc]; 在QuestionDetailView控制器中。

为什么?我记录问题详细信息视图控制器重新计数。看起来不错。

问题详细视图控制器

#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

表视图:didselectrowatindexpath:

- (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];
}

2 回复 | 直到 15 年前

Dave DeLong 15 年前

这是:

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

看起来非常可疑。你做了吗 [self retain] ?如果没有,那你为什么要释放?如果你是,你可能做错了什么,因为 [自我保留] 是一件非常罕见的事情需要去做。

Johan Kool 15 年前

而不是:

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

用途:

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

或:

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