Question

首先让我为我糟糕的英语道歉。所以我试图做这个程序，从另一个类中获取一个类中的NSString的值。这是代码：

/---------------------/tableViewController.h -----------

#import <UIKit/UIKit.h>
@class paisesDetailViewController;

@interface tableViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource>{
    IBOutlet UITableView *paisesTableView;
    paisesDetailViewController *PaisesDetailViewController;

    //DB
    NSString *DBName;
    NSString *DBPath;
    NSMutableArray *ArrayPais; //means Countrys
    NSString *escolha; //means choise 
}

@property(nonatomic, retain) paisesDetailViewController *PaisesDetailViewController;
@property(nonatomic, retain) NSMutableArray *ArrayPais;
@property(nonatomic, retain) NSString *escolha;

@end




-----------------------------//tableViewController.m---------------

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
   NSInteger row = [indexPath row];
    if(self.PaisesDetailViewController == nil)
    {
        paisesDetailViewController *apaisesDetail = [[paisesDetailViewController alloc] initWithNibName:@"paisesDetailView" bundle:nil];
        self.PaisesDetailViewController = apaisesDetail;
        [apaisesDetail release];
    }

    [tableView deselectRowAtIndexPath:indexPath animated:YES];

    escolha = [[NSString alloc] init];
    self.escolha = [NSString stringWithFormat:@"%@", [ArrayPais objectAtIndex:(row)]]; 

    paisesDetailViewController *nextview = [[paisesDetailViewController alloc] init];
    [self.navigationController pushViewController:nextview animated:YES];
    [nextview release];

}




-----------------------------------//paisesDetailViewController.h------------
#import <UIKit/UIKit.h>
#import "tableViewController.h"
@class tableViewController;

@interface paisesDetailViewController : UIViewController {
    tableViewController *dados;

}

@property(nonatomic, retain) tableViewController *dados;

@end


//-----------------------paisesDetailViewController.m
#import "paisesDetailViewController.h"
#import "tableViewController.h"

@implementation paisesDetailViewController
@synthesize dados;

-(IBAction) createEvent
{
        NSString *help = [[NSString alloc] initWithString: dados.escolha]; 
}

问题是'dados.escolha'总是零，我只是不明白为什么。谢谢你的帮助。

Answer 1

试试这个，

paisesDetailViewController *nextview = [[paisesDetailViewController alloc] init];
nextView.dados = self;
[self.navigationController pushViewController:nextview animated:YES];
[nextview release];

更新：

试试这段代码：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSInteger row = [indexPath row];
    if(self.PaisesDetailViewController == nil)
    {
        paisesDetailViewController *apaisesDetail = [[paisesDetailViewController alloc] initWithNibName:@"paisesDetailView" bundle:nil];
        self.PaisesDetailViewController = apaisesDetail;
        [apaisesDetail release];
    }

    [tableView deselectRowAtIndexPath:indexPath animated:YES];

    escolha = [[NSString alloc] init];
    self.escolha = [NSString stringWithFormat:@"%@", [ArrayPais objectAtIndex:(row)]]; 

    paisesDetailViewController *nextview = [[paisesDetailViewController alloc] init];
    nextView.dados = self;
    [self.navigationController pushViewController:nextview animated:YES];
    [nextview release];
}

Answer 2

确保包含

@synthesize escolha;

tableViewController.m中的

。还要确保在paisesDetailViewController.m中分配并实例化dados

tableViewController *dados = [[tableViewController alloc] init];

然后尝试使用

-(IBAction) createEvent
{
        NSString *help = dados.escolha; 
}

此外，您的大写惯例是倒退的。通常，类名是大写的，而实例不是，例如， MyObject *myObject。

Answer 3

-(IBAction) createEvent
{
    NSString *help = [[NSString alloc] init];

    help = [NSString stringWithFormat: @"%@", self.dados.escolha]; 

    NSLog(@"help is : %@ ", help);

    // You have synthesized them, so use with self
}

iPhone：从另一个类访问NSString值

3 个答案: