iOS将数据从tableview传递到新视图

Question

我正密切关注这个群组http://klanguedoc.hubpages.com/hub/iOS-How-To-Display-Detail-Data-from-UITableView-in-Detail-View-Controller，并且能够几乎完美地复制它，除了最终组件。 prepareForSegue方法。

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([[segue identifier] isEqualToString:@"showDetail"]) {
        klViewController *detailViewController = [segue destinationViewController];

        detailViewController.treeData = [self.ds objectAtIndex:[self.tableView indexPathForSelectedRow].row];

    }
}

我试着仔细观察并尝试找到prepareForSegue方法的其他在线示例，但它们都指向相同的方向，这意味着方法和代码是正确的！

xcode发出的错误是ARC问题 - 'NSString'没有可见的@interface声明选择器'isEqualToString：'

任何人都可以指出我正确的方向吗？

如果我错了，请纠正我，但是这个prepareForSegue方法应该假设在tableview类中吗？如果它不是请让我知道，因为我是xcode的新手，教程很朦胧，因此我害怕错过解释代码的位置。

非常感谢提前：）

编辑：

SampleData.h

#import <Foundation/Foundation.h>

@interface SampleData : NSObject

@property (nonatomic,strong) NSString * treeName;
@property (nonatomic,strong) NSString * treeDescription;

@end

SampleData.m

#import "SampleData.h"

@implementation SampleData
@synthesize treeName, treeDescription;


@end

SampleDataDOA.h

#import <Foundation/Foundation.h>
#import "SampleData.h"
@interface SampleDataDAO : NSObject

@property (nonatomic,strong) NSMutableArray *someDataArray;

-(NSMutableArray *)PopulateDataSource;

@end

SampleDataDOA.m

#import "SampleDataDAO.h"

@implementation SampleDataDAO

@synthesize someDataArray;



-(NSMutableArray *)PopulateDataSource
{
    someDataArray= [[NSMutableArray alloc]initWithCapacity:3];
    SampleData * mydata= [[SampleData alloc]init];

    mydata.treeName = @"Oak";
    mydata.treeDescription = @"an oak is a tree or shurb bla bla bla";
    [someDataArray addObject:mydata];
    mydata=nil;

    mydata=[[SampleData alloc]init];
    mydata.treeName=@"Douglas Fir";
    mydata.treeDescription=@"Douglas Fir are medium-size to extremely large evergreen trees";
    [someDataArray addObject:mydata];
    mydata=nil;

    mydata=[[SampleData alloc]init];
    mydata.treeName=@"Sugar Maple";
    mydata.treeDescription=@"Sugar Maple is a species of Maple. Sugar Maple is best known for it's sweet leaves as it contain natural sugar and is extremely healthy and beneficial to our health";
    [someDataArray addObject:mydata];
    mydata=nil;



    return someDataArray;
}


@end

TableViewController.h

#import <UIKit/UIKit.h>
#import "SampleDataDAO.h"
#import "SampleData.h"
#import "ViewController.h"

@interface TableViewController : UITableViewController

@property(nonatomic,strong) SampleDataDAO* daoDS;
@property (nonatomic,strong) NSMutableArray *ds;


@end

TableViewController.m（方法prepareForSegue出错）

#import "TableViewController.h"

@interface TableViewController ()

@end

@implementation TableViewController
@synthesize daoDS,ds;

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if( [[segue identifier] isEqualtoString:@"showDetail"]){        
        ViewController * detailViewController = [segue destinationViewController];

        detailViewController.treeData=[self.ds objectAtIndex:[self.tableView indexPathForSelectedRow].row];
    }
}


- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    daoDS = [[SampleDataDAO alloc]init];
    self.ds = daoDS.PopulateDataSource;

    // Uncomment the following line to preserve selection between presentations.
    // self.clearsSelectionOnViewWillAppear = NO;

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{

    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    // Return the number of rows in the section.
    return 3;
}   

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"treeCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil){
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
    // Configure the cell...
    SampleData * sample = [self.ds objectAtIndex:indexPath.row];
    cell.textLabel.text = sample.treeName;
    NSLog(@"Cell Value %d %@", indexPath.row, cell.textLabel.text);




    return cell;
}





/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}
*/

/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
    }   
    else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}
*/

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the item to be re-orderable.
    return YES;
}
*/

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Navigation logic may go here. Create and push another view controller.
    /*
     <#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
     // ...
     // Pass the selected object to the new view controller.
     [self.navigationController pushViewController:detailViewController animated:YES];
     */
}

@end

ViewController.h

#import <UIKit/UIKit.h>
#import "SampleData.h"
@interface ViewController : UIViewController
@property (strong, nonatomic) IBOutlet UITextView *treeInfo;
@property (nonatomic, strong) SampleData * treeData;

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize treeData, treeInfo;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}   

@end

P.S - 代码几乎与网站上的1相似，主要区别在于我删除了代码的图片部分。

编辑 - 错误日志文件 'NSString'没有可见的@interface声明选择器'isEqualtoString：'     if（[[segue identifier] isEqualtoString：@“showDetail”]）{

错误下划线是“[[”希望这对你们找出真正的错误是一个有用的暗示._。

Answer 1

因此，当您处理iOS时，您处于MVC架构中，这意味着您拥有控制故事板的ViewControllers，因此您的prepareForSegue方法应该位于与正在转换的视图对应的ViewController类中。

也许在右侧的身份检查员中查看您的故事板。确保“自定义类”是您正在使用的具有prepareForSegue方法的视图控制器

没有看到更多的代码，很难说，但这个链接似乎可能有你需要的东西："No visible @interface for 'BlahDataController' declares the selector 'aMethod:'"

如果此链接不起作用，请尝试再次查看给定教程的每个步骤。你可能会找到一些东西

干杯

Answer 2

首先，改变：

if ([[segue identifier] isEqualToString:@"showDetail"]) {

到

if ([segue.identifier isEqualToString:@"showDetail"]) {

和

klViewController *detailViewController = [segue destinationViewController];

到

klViewController *detailViewController = segue.destinationViewController;

另外，我倾向于将segue连接到ViewController或TableViewController本身，而不是连接到tableview单元格。然后在cellForRowAtIndexPath中，我会触发segue并传入IndexPath，如下所示：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    [self performSegueWithIdentifier:@"showDetail" sender:indexPath];
}

然后使用你的prepareForSegue方法，我会这样做：

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([segue.identifier isEqualToString:@"showDetail"]) {
        // Get the indexPath
        NSIndexPath *indexPath = (NSIndexPath *)sender;

        klViewController *detailViewController = segue.destinationViewController;
        detailViewController.treeData = [self.ds objectAtIndex:indexPath.row;
    }
}