当核心数据状态改变时，UISwitch不会打开

Question

我有一个表，其中每一行代表核心数据中的一个对象。每行都包含一个 UISwitch（修改为包含包含它的行的索引路径），切换时应切换核心数据中对象的状态属性。

目前发生的情况是，触摸开关时开关会变为打开状态，然后又返回关闭状态！？

我得到的唯一线索是，当我注释掉

// Establish what position the switch should be in
    if([info.state isEqualToString:@"on"]){
        mySwitch.selected = TRUE;
    } else {
        mySwitch.selected = FALSE;
    }

以及changeState 方法中的两行info.state 行时，开关工作正常。看起来 info.state 设置器，无论它们对开关状态的影响如何，都会阻止开关切换。

我是否只是非常疏忽并且没有正确管理内存？

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }

    // Configure the cell...
    [self configureCell:cell atIndexPath:indexPath];
    return cell;
}

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath {
    InfoObject *info = [self.fetchedResultsController objectAtIndexPath:indexPath];
    cell.textLabel.text = info.name;

    // Use a custom UISwitch that holds a pointer to the row it is associated with
    NamedUISwitch *mySwitch = [[[NamedUISwitch alloc] initWithFrame:CGRectZero] autorelease];
    mySwitch.indexPath = indexPath;
    [mySwitch addTarget:self action:@selector(changeState:) forControlEvents:UIControlEventValueChanged];
    // And of course we need to know what the state is
    NSLog(@"switchState:%@",info.state);

    // Establish what position the switch should be in
    if([info.state isEqualToString:@"on"]){
        mySwitch.selected = TRUE;
    } else {
        mySwitch.selected = FALSE;
    }

    cell.accessoryView = mySwitch;
}

- (void) changeState:(id)sender {
    InfoObject *info = [self.fetchedResultsController objectAtIndexPath:((NamedUISwitch*)sender).indexPath];

    if(((NamedUISwitch*)sender).on){
        info.state = @"on";
    } else {
        info.state = @"off";
    }

    NSError *error;
    if (![self.context save:&error]) {
        NSLog(@"Whoops, couldn't save state: %@", [error localizedDescription]);
        //TODO: alertview
    }
}

Answer 1

我认为代码应该是：

// Establish what position the switch should be in
    if([info.state isEqualToString:@"on"]){
        mySwitch.on = YES;
    } else {
        mySwitch.on = NO;
    }