iPhone:UISegmentedControl，如何让导航返回后记住索引？

Question

我的 tableview Controller 上有一个段。

segmentIndex=0 -> tableView 正在加载 -> 点击。导航到另一个 tableViewController。segmentIndex=1 -> tableView 正在加载 -> 点击。导航到另一个 tableViewController。

切换 TableView 很顺利。问题是导航回来后我需要记住以前的索引值。如何实现？我当前的代码:

- viewWillAppear
self.segment=[[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Nominals",@"Coinage",nil]];
[self.segment setFrame:CGRectMake(80, 0, 200, 30)];
[self.segment setSegmentedControlStyle:UISegmentedControlStyleBar];
//self.segment.selectedSegmentIndex=0;
[self.segment addTarget:self action:@selector(segmentValueChaged:) forControlEvents:UIControlEventValueChanged];
[[self navigationItem] setTitleView:self.segment];


-(IBAction)segmentValueChaged:(id)sender
{
switch (self.segment.selectedSegmentIndex) 
{
    case 0:
    {
        DBAccess *access=[[DBAccess alloc]init];
        self.items=[access returnNominals:self.subCountryID nk:fromPeriod];
        [access closeDataBase];
        self.tableView.hidden=NO;
        [self.tableView reloadData];
        self.segmentIndex=0;
         break;
    }
    case 1:
    {
        DBAccess *access=[[DBAccess alloc]init];
        self.coinageArr=[access returnCoinage:fromPeriod period:subCountryID];
        self.tableView.hidden=NO;
        [self.tableView reloadData];
        self.segmentIndex=1;
        break;
    }
}
}

提前谢谢你们。

编辑:

self.segment=[[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Nominals",@"Coinage",nil]];
[self.segment setFrame:CGRectMake(80, 0, 200, 30)];
[self.segment setSegmentedControlStyle:UISegmentedControlStyleBar];
if(!self.segmentIndex)
{
    self.segment.selectedSegmentIndex=-1;
}
else 
{
    self.segment.selectedSegmentIndex=self.segmentIndex;
}

//self.segment.selectedSegmentIndex=self.segmentIndex;
[self.segment addTarget:self action:@selector(segmentValueChaged:) forControlEvents:UIControlEventValueChanged];
[[self navigationItem] setTitleView:self.segment];


-(void)viewWillDisappear:(BOOL)animated
{
switch (self.segment.selectedSegmentIndex) 
{
    case 0:
    {
        self.segmentIndex=0;
        break;
    }
    case 1:
    {
        self.segmentIndex=1;
        break;
    }
}

}

Answer 1

您将您的值存储在 viewWillDisappear 中，当您返回到您的 Controller viewWillAppear 时，您将设置回您存储的值。所以你还可以做的是，首先将值设置为...比方说-1。如果在您的 viewWillAppear 中值为 -1，则您设置默认值，否则，您使用该值。

- (void)viewWillAppear:(BOOL)animated {
    self.segment=[[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Nominals",@"Coinage",nil]];
    [self.segment setFrame:CGRectMake(80, 0, 200, 30)];
    [self.segment setSegmentedControlStyle:UISegmentedControlStyleBar];

    if (self->_currentIndex == -1) {
        NSInteger myDefaultValue = 0;
        self.segment.selectedSegmentIndex=myDefaultValue;
    } else {
        self.segment.selectedSegmentIndex=self->_currentIndex;
    }

   [self.segment addTarget:self action:@selector(segmentValueChaged:) forControlEvents:UIControlEventValueChanged];
   [[self navigationItem] setTitleView:self.segment];
}

当 Controller 即将消失时，您还必须存储该值。

- (void)viewWillDisappear:(BOOL)animated {
    self->_currentIndex = self.segment.selectedSegmentIndex;
}

在界面中定义 NSInteger _currentIndex; 的地方