是否將autorelease對象分配給保留屬性會增加其保留數？

Question

我會想'self.data ='會保留autorelease NSMutableArray對象和它包含的NSMutableDictionary對象，但是當表格的cellForRowAtIndexPath方法試圖訪問self.data中的NSDictionaries時，我最終得到EXC_BAD_ACCESS。

@property (strong, nonatomic) NSMutableArray *data; 

- (void) updateReceivedData:(NSData *) jsonData 
{ 
    NSMutableArray *fetchedData = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error]; 
     self.data = [self convertDates:fetchedData withFormat:kMySQLDateTimeFormat]; 
     [self.tableView reloadData]; 
    } 
} 

- (NSMutableArray*) convertDates:(NSMutableArray *) array withFormat:(NSString *) format 
{ 
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
    [dateFormatter setDateFormat:format]; 
    NSMutableArray *newArray = [NSMutableArray arrayWithArray:array]; 
    for (NSMutableDictionary *dict in newArray) 
    { 
     for (id key in dict.allKeys) 
     { 
      if ([[dict objectForKey:key] isKindOfClass:[NSString class]]) 
      { 
       NSString *value = [dict objectForKey:key]; 
       NSDate *date = [dateFormatter dateFromString:value]; 
       if (date) [dict setObject:date forKey:key]; 
      } 
     } 
    } 
    [dateFormatter release]; 
    return newArray; 
} 

BAD_ACCESS HERE在NSLog之間拋出這裏。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *CellIdentifier = @"cell"; 
    CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 

    if (cell == nil) { 
     NSLog (@"Cell was nil"); 
     cell = [[[CustomCell alloc] init] autorelease]; 
    } 

    NSDictionary *dict = [[NSDictionary alloc] init]; 
    if (_isFiltered){ 
     dict = [self.filteredData objectAtIndex:indexPath.row]; 
    } else { 
     dict = [self.data objectAtIndex:indexPath.row]; 
    } 
    NSLog (@"Filling Label 1"); 
    cell.IDLabel.text = [[dict objectForKey:@"Id"] stringValue]; 
    NSLog (@"Filling Label 2"); 
    cell.firstNameLabel.text = [dict objectForKey:@"firstName"]; 
    [dict release]; 
    return cell; 
} 

Answer 1

打開殭屍，看看它是否抓住了問題（EXC_BAD_ACCESS並不一定意味着過度釋放的對象，但它可能）。

對象的保留計數的絕對值無關緊要。

但是，strong屬性意味着該對象被保留，是的，如果您通過setter（即self.data = ...而不是_data = ...）進行分配。

Answer 2

你爲什麼要在cellForRowAtIndexPath中釋放字典：儘管你分配字典，你正在分配另一個指針，這是來自filteredData或數據的對象。只要刪除[數據發佈]，同時聲明數據分配爲零

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *CellIdentifier = @"cell"; 
    CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 

    if (cell == nil) { 
     NSLog (@"Cell was nil"); 
     cell = [[[CustomCell alloc] init] autorelease]; 
    } 

    // **As you will be assigning the object from filteredData/data, don't allocate here** 
    NSDictionary *dict = nil; 
    if (_isFiltered){ 
     dict = [self.filteredData objectAtIndex:indexPath.row]; 
    } else { 
     dict = [self.data objectAtIndex:indexPath.row]; 
    } 
    NSLog (@"Filling Label 1"); 
    cell.IDLabel.text = [[dict objectForKey:@"Id"] stringValue]; 
    NSLog (@"Filling Label 2"); 
    cell.firstNameLabel.text = [dict objectForKey:@"firstName"]; 
    // **Release not required as you didn't allocate** 
    //[dict release]; 
    return cell; 
}