ios - 在表格视图中保存选定的行并返回主屏幕 UIButtons

Question

Plz code Help 谁能告诉我如何完成这项任务？在主屏幕中，用户选择足球运动员，在表格视图单元格的第二个屏幕中，用户选择特定行并保存该行并返回主视图。在主视图中，它会显示特定行的视频。基本上我想知道特定的行选择，将该选择保存在表格视图中并在主屏幕中显示他们的内容。

Answer 1

通过下面的代码，它实现了委托概念，也实现了你的问题的解决方案希望这对你有帮助:)

  //in your main view controller

  #import "ViewController.h"
  #import "FootBallPlayersViewController.h"

  @interface ViewController ()<FootballPlayerDelegate>//confirms to this delegate 

  @end

  @implementation ViewController

  - (void)viewDidLoad
   {
        [super viewDidLoad];



// Do any additional setup after loading the view, typically from a nib.
   }

 - (IBAction)whenSelectButtonClicked:(id)sender
   {
        FootBallPlayersViewController *controller = [[FootBallPlayersViewController alloc]initWithNibName:@"FootBallPlayersViewController" bundle:nil];
        controller.delegate = self; //u must set to self
        [self presentViewController:controller animated:YES completion:nil];


   }

  - (void)didReceiveMemoryWarning
  {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
  }

  - (void)selectedFootBallPlayer:(NSString *)player
    {
      //implementation of your delegate method

      //hear u are getting the football player name and u can continue further hear
       NSLog(@"%@",player);
      if([player isEqualToString:@"player1"])
        {
          UIButton *aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
          [aButton setTitle:player forState:UIControlStateNormal];
          [aButton addTarget:self action:@selector(whenFirstPlayerButtonClicked:) forControlEvents:UIControlEventTouchUpInside]; //add the target to self for click events 
          aButton.frame = CGRectMake(50, 50, 200, 55);
          [self.view addSubview:aButton];

       }
     else
      {
       UIButton *aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
       [aButton setTitle:player forState:UIControlStateNormal];
       aButton.frame = CGRectMake(50, 105, 200, 55);
        [aButton addTarget:self action:@selector(whenSecondPlayerButtonClicked:) forControlEvents:UIControlEventTouchUpInside]; //same hear
       [self.view addSubview:aButton];

      }


  }
   //now define the action methods 
 - (void)whenFirstPlayerButtonClicked:(UIButton *)sender
  {

       NSLog(@"player 1 video start");    
  }

  - (void)whenSecondPlayerButtonClicked:(UIButton *)sender
  {
       NSLog(@"player 2 video start ");
  }


  @end

在包含 tableview 的视图中做这样的事情

//在FootBallPlayersViewController.h中

   #import <UIKit/UIKit.h>
     @protocol FootballPlayerDelegate <NSObject>     //define a protocol named      FootballPlayerDelegate
    - (void)selectedFootBallPlayer:(NSString *)player;
    @end

   @interface FootBallPlayersViewController : UIViewController
    {
       NSArray *players;
       NSString *selectedPlayer;
    }

   @property (retain, nonatomic) IBOutlet UITableView *playerTable;
   @property (nonatomic, assign) id<FootballPlayerDelegate>delegate; //create a delegate

   @end

在你的FootBallPlayersViewController.m文件中

   #import "FootBallPlayersViewController.h"

   @interface FootBallPlayersViewController ()<UITableViewDataSource,UITableViewDelegate>
     {


    }
   @end

   @implementation FootBallPlayersViewController
   @synthesize delegate; //synthesizing the delegate

   - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
   {
      self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
      if (self) {
      // Custom initialization
         }
     return self;
    }

    - (void)viewDidLoad
   {
       [super viewDidLoad];
        players = [[NSArray alloc]initWithObjects:@"player1",@"player2", nil];
      // players = [[NSArray alloc]initWithObjects:@"player1","player2", nil];
     // Do any additional setup after loading the view from its nib.
   }

    - (void)didReceiveMemoryWarning
    {
      [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
    }

   - (void)dealloc
  {
      [players release];
      [_playerTable release];
      [super dealloc];
  }
 - (IBAction)whenDoneButtonClicked:(id)sender {
      //when done button clicked -->
      //send a delegate to main controller
      if([self.delegate respondsToSelector:@selector(selectedFootBallPlayer:)])//to avoid crash
        {
          [self.delegate selectedFootBallPlayer:selectedPlayer]; //call the delegate method hear
        }
     //dismiss the view
     [self dismissViewControllerAnimated:YES completion:nil];

    }


    - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
     {
        return 1;
      }

     - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
    {
         return players.count;
    }

     - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
   {

        UITableViewCell *cell = [tableView dequeueReusableHeaderFooterViewWithIdentifier:@"cell"];
        if(cell == nil)
       {
          cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
       }

        cell.textLabel.text = [players objectAtIndex:indexPath.row];
        return cell;
   }

   - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
   {
      //u can manage check mark and all, i am getting the selected player name
     selectedPlayer = [players objectAtIndex:indexPath.row];
    }

 @end

Answer 2

简单的解决方案... 由于您是新手，我正在澄清每一点。

1. 首先在 AppDelegate.h 中创建一个属性

   @property int selectedRow;

2. 将选定的 indexpath.row 保存在第二个屏幕中，即您的表格视图屏幕，并导入 AppDelegate.h

   (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
      {   
        self.appDelegate=(AppDelegate *)[[UIApplication sharedApplication] delegate];
        self.appDelegate.selectedRow=indexPath.row; //saving the row
   
       }
   

3. 在主屏幕的 viewWillAppear()

   -(void)viewWillAppear:(BOOL)animated
     {
        if(self.appDelegate.selectedRow!=-1)//check wether row is selected or not
            {
   
                //action to show the specific row videos
   
             }
      }
   

Answer 3

实现此目的的好方法：

1. 自定义委托
2. NSNotificationCenter
3. NSUserDefaults（编辑：不必要的磁盘写入）
4. 维护一个 Common NSObject 子类并刷新数据-willAppear

其他方法：

1. 数据库（核心数据/SQLite）或 plist（对于您的情况来说太重了）（编辑：不必要的磁盘写入）
2. UIPasteBoard

---

快速委托教程：

---

第 1 部分：创建委托

假设这是在UITableViewController我命名的子类的 .h 中YourTableViewControllerClassName

//declare the protocol
@class YourTableViewControllerClassName;
@protocol YourTableViewControllerClassNameDelegate <NSObject>
//@required    //uncomment to specify required delegate methods as below
//- (void)requiredMethodNotUsedForThisExample;
@optional
- (void)selectedRow: (NSString *)selectedObj;
@end

@interface YourTableViewControllerClassName : UITableViewController
//declare a weak property to store any object
@property (nonatomic, weak) id <YourTableViewControllerClassNameDelegate> delegate;
@end

---

假设这是-didSelectRowAtIndexPath相应UITableViewController子类的：

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    //the following line is the main thing and can be called
    //in any method within this class (placed wisely)
    if([[self delegate] respondsToSelector:@selector(selectedRow)]) { //avoid crash
        [[self delegate] selectedRow:cell.textLabel.text];    
    }
    [self.navigationController popViewControllerAnimated:YES];
}

---

第 2 部分：实现委托

假设这是前一个UIViewController子类中某处的代码：

//call this method somewhere
-(void)pushMyTableViewController
{
    //declare "UILabel lblText;" in the .h of this class
    //lblText = [UILabel alloc] init];
    //[lblText setFrame: CGRectMake(0,0,100,35)];
    //[self.view addSubview:lblText];

    YourTableViewControllerClassName *tvcObj = [[YourTableViewControllerClassName alloc] init];
    //for the following line, remember to declare
    //<YourTableViewControllerClassNameDelegate> in the .h of this class
    //hence declaring that this class conforms to the delegate protocol
    [tvcObj setDelegate:self];
    [self.navigationController pushViewController:tvcObj animated:YES];
}

---

这将是您可以在前一个UIViewController子类中实现的委托方法：

#pragma mark - Optional YourTableViewControllerClassName Delegate Methods
-(void)selectedRow:(NSString *)selectedObj
{
    [lblText setText:selectedObj];
}

---

注意：这不会解决您的特定问题，因为我们仅根据UITableViewController子类中的选定行设置标签。
重点是展示委托是如何工作的。
此外，如果您可以在前cell.textLabel.text一个类中获取并设置它，那么您可以在适当的位置进行更改（主要是 中的方法/s ）并传递所选项目的数组索引或任何对象/变量/其他让你的生活更轻松UILabel@protocol

*如果你想要一些更简单的东西，那就去NSNotificationCenter或者NSUserDefaults甚至可能UIPasteBoard（如果它漂浮你的船）

Answer 4

选择任何行时使用调用的 tableView 委托

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
   AppDelegate* appDelegate = [UIApplication sharedApplication].delegate;
   appDelegate.selectedindex = indexpath.row;

   or

   [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithInt:indexpath.row] forKey:@"SelcetedIndex"];
}

那么你可以做 3 件事来获得你选择的索引

1）为索引路径创建一个应用程序委托变量，以便您可以在此处设置并获取其他控制器上的值

// 在 appDelegate 文件中添加属性 @property int selectedIndex;

2) 使用 NSUserDefault 设置选中的索引值

// read userDefault value 
[[[NSUserDefaults standardUserDefaults] objectForKey:@"SelcetedIndex"] intValue];

3）使用委托将值返回给前一个控制器

// 尝试 google 并首先了解这个概念，如果你想使用 delgate，请告诉我