我有两个通过展开segue连接的控制器。第一个视图有一个表格，表示：Auction，Make，Model为三行。当用户点击“拍卖”行时，它会将它们发送到之前拍卖的桌面视图。
我想要做的是在第一个视图上显示拍卖（从第二个视图点击）。我有解开的segue工作，但当我尝试创建一个静态变量来保存文本时，它会在转回时自行更改为NULL。例如，我设置了一个名为“标签”的static NSString。单击第二个表视图中的行时，标签将更改为该单元格的文本值。但是当我将它传回segue时，它会变为NULL。
这是第一个观点：
#import "searchCar.h"
#import "auctionTable.h"
@implementation searchCar
@synthesize auctionLabel;
- (IBAction)unwindToList:(UIStoryboardSegue *)segue
{
auctionTable *unwoundSegue = segue.sourceViewController;
self.auctionLabel.text = unwoundSegue.auctionName;
}
@end
以下是第二个观点：
#import "searchCar.h"
#import "auctionTable.h"
static NSString *label;
@implementation auctionTable
@synthesize auctionName;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//Default section data
self.defaultItemsArray=@[@"All"];
//First section data
self.firstItemsArray = @[@"Houston, TX 4/2014",@"Davenport, IA 4/2014",@"Kissimmee, FL 1/2014",@"Las Vegas, NV 1/2014"];
//Second section data
self.secondItemsArray = @[@"Kansas City, MO 12/2013",
@"Anaheim, CA 11/2013",
@"Davenport, IA 11/2013",
@"Schaumburg, IL 10/2013",
@"Dallas, TX 9/2013",
@"Monterey, CA 8/2013",
@"Walworth, WI 8/2013",
@"Santa Monica, CA 7/2013",
@"Des Moines, IA 7/2013",
@"West Allis, WI 7/2013",
@"Champaign , IL 6/2013",
@"Indianapolis, IN 5/2013",
@"Kansas City, MO 4/2013",
@"Houston, TX 4/2013",
@"Davenport, IA 4/2013",
@"Boynton Beach, FL 2/2013",
@"Kissimmee, FL 1/2013"];
//Third section data
self.thirdItemsArray = @[@"Kansas City, MO 12/2012",
@"Anaheim, CA 11/2012",
@"Davenport, IA 11/2012",
@"St Charles, IL 10/2012",
@"Dallas, TX 9/2012",
@"Monterey, CA 8/2012",
@"Walworth, WI 8/2012",
@"Des Moines, IA 7/2012",
@"West Allis, WI 7/2012",
@"St. Charles, IL 6/2012",
@"St. Paul, MN 6/2012",
@"North Little Rock, AR 6/2012",
@"Indianapolis, IN 5/2012",
@"Houston, TX 4/2012",
@"Walworth, WI 4/2012",
@"Kansas City, MO 3/2012",
@"Kissimmee, FL 1/2012"];
//Fourth section data
self.fourthItemsArray = @[@"Kansas City, MO 12/2011",
@"Dallas, TX 10/2011",
@"Fontana, WI 9/2011",
@"St. Charles, IL 9/2011",
@"Monterey, CA 8/2011",
@"Walworth, WI 8/2011",
@"Des Moines, IA 7/2011",
@"West Allis, WI 7/2011",
@"St. Charles, IL 6/2011",
@"St. Paul, MN 6/2011",
@"Indianapolis, IN 5/2011",
@"Walworth, WI 3/2011",
@"Kansas City, MO 3/2011",
@"Kissimmee, FL 1/2011"];
//Fifth section data
self.fifthItemsArray = @[@"Kansas City, MO 12/2010",
@"Canal Winchester, OH 11/2010",
@"Ft. Lauderdale, FL 10/2010",
@"Winsted, MN 10/2010",
@"St. Charles, IL 9/2010",
@"Monterey, CA 8/2010",
@"Walworth, WI 8/2010",
@"Des Moines, IA 7/2010",
@"St. Charles, IL 6/2010",
@"St. Paul, MN 6/2010",
@"Indianapolis, IN 5/2010",
@"Kansas City, MO 4/2010",
@"Kissimmee, FL 1/2010"];
//Sixth section data
self.sixthItemsArray = @[@"Kansas City, MO 12/2009",
@"Branson, MO 10/2009",
@"St. Charles, IL 10/2009",
@"Canal Winchester, OH 9/2009",
@"Monterey, CA 8/2009",
@"Des Moines, IA 7/2009",
@"St. Charles, IL 6/2009",
@"St. Paul, MN 6/2009",
@"Indianapolis, IN 5/2009",
@"Kansas City, MO 3/2009",
@"Kissimmee, FL 1/2009"];
//Seventh section data
self.seventhItemsArray = @[@"Kansas City, MO 12/2008",
@"St. Charles, IL 10/2008",
@"Canal Winchester, OH 9/2008",
@"Des Moines, IA 7/2008",
@"St. Charles, IL 6/2008",
@"St. Paul, MN 6/2008",
@"Indianapolis, IN 5/2008",
@"Kissimmee, FL 1/2008"];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 7;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
if(section == 0)
return @"Default";
else if(section == 1)
return @"2014";
else if(section == 2)
return @"2013";
else if(section == 3)
return @"2012";
else if(section == 4)
return @"2011";
else if(section == 5)
return @"2010";
else if(section == 6)
return @"2009";
else if(section == 7)
return @"2008";
else
return 0;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection: (NSInteger)section
{
if(section == 0)
return [self.defaultItemsArray count];
else if(section == 1)
return [self.firstItemsArray count];
else if(section == 2)
return [self.secondItemsArray count];
else if(section == 3)
return [self.thirdItemsArray count];
else if(section == 4)
return [self.fourthItemsArray count];
else if(section == 5)
return [self.fifthItemsArray count];
else if(section == 6)
return [self.sixthItemsArray count];
else if(section == 7)
return [self.seventhItemsArray count];
else
return 0;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"auctionCell"];
if(indexPath.section == 0)
{
cell.textLabel.text = [self.defaultItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 1)
{
cell.textLabel.text = [self.firstItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 2)
{
cell.textLabel.text = [self.secondItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 3)
{
cell.textLabel.text = [self.thirdItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 4)
{
cell.textLabel.text = [self.fourthItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 5)
{
cell.textLabel.text = [self.fifthItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 6)
{
cell.textLabel.text = [self.sixthItemsArray objectAtIndex:indexPath.row];
}
else if(indexPath.section == 7)
{
cell.textLabel.text = [self.seventhItemsArray objectAtIndex:indexPath.row];
}
else{
cell.textLabel.text = @"Not Found";
}
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
label = cell.textLabel.text;
}
-(void) prepareForSegue: (UIStoryboardSegue *)segue sender: (id)sender {
if ([segue.identifier isEqualToString:@"completeEntry"]) {
self.auctionName = label;
}
}
@end
答案 0 :(得分：1)
您的代码无效的原因是因为在didSelectRowAtIndexPath之前调用了prepareForSegue。使用segues时，最好不要实现didSelectRowAtIndexPath。您可以在prepareForSegue：sender：中获取从sender参数中选择的单元格。你的代码应该是这样的，
-(void) prepareForSegue: (UIStoryboardSegue *)segue sender: (UITableViewCell *)sender {
if ([segue.identifier isEqualToString:@"completeEntry"]) {
_label = sender.textLabel.text;
self.auctionName = _label;
}
}
从单元格获取数据通常也不是一个好习惯，单元格用于显示数据，而不是提供数据，但是设置数据源的方式使得这有点困难。不是拥有多个数组，而是拥有一个阵列的单个数组（然后你不需要所有其他的 - 如果是），你将拥有更清晰的代码。
答案 1 :(得分：0)
为什么不使用
(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
self.auctionName = cell.textLabel.text;
}
？并摆脱prepareForSegue
auctionTable
您没有显示@property的{{1}}定义，但应将其定义为
auctionName副本将确保您获得字符串的副本，而不是引用可能已取消分配的字符串。
顺便说一下，作为一种风格问题，@property (copy,nonatomic) NSString *auctionName
应该是auctionTable而AuctionTable应该是searchCar - 类以大写字母开头。