在方法objective-c之外保留数组数据

Question

我有一个数组，players，其中有两个字符串:player1和player2。这是我的。h文件:

#import <UIKit/UIKit.h>
@interface hardOne : UIViewController {
        UISwitch *hard1ON;
        NSMutableArray *players;
        NSString *player1, *player2;
}
@property (nonatomic, retain) IBOutlet UISwitch *hard1ON;
@property (nonatomic) BOOL switchState;
@property (nonatomic, retain) NSMutableArray *players;
- (IBAction) switchValueChanged;
@end

数组在viewDidLoad中初始化，然后数据在我的。m文件中的两个IBActions中输入到数组中:

#import "hardOne.h"
@interface hardOne () <UITextFieldDelegate>
@property (nonatomic, strong) IBOutlet UITextField *textFieldOne;
@property (nonatomic, strong) IBOutlet UITextField *textFieldTwo;
@end
@implementation hardOne
@synthesize hard1ON;
@synthesize players;
@synthesize textFieldOne;
@synthesize textFieldTwo;
BOOL switchState;
int counter = 0;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    [hard1ON setOn:switchState animated:NO];
    //read player names to user defaults
    [textFieldOne setText:[[NSUserDefaults standardUserDefaults] stringForKey:@"player1"]];
    [textFieldTwo setText:[[NSUserDefaults standardUserDefaults] stringForKey:@"player2"]];
    self.players = [[NSMutableArray alloc] init];
    NSLog(@"%@",self.players);
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (IBAction) switchValueChanged
{
    counter += 1;
    if (counter % 2 == 0) {
        switchState = 0;
    } else {
        switchState = 1;
    }
    if (hard1ON.on) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"theChange" object:nil];
    } else {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"theChange2" object:nil];
    }
}
- (IBAction) returnKey1
{
    player1 = [textFieldOne text];
    [self.players addObject:(player1)];
    //set player1's name to user defaults
    [[NSUserDefaults standardUserDefaults] setValue:[textFieldOne text] forKey:@"player1"];
}
- (IBAction) returnKey2
{
    player2 = [textFieldTwo text];
    [self.players addObject:(player2)];
    //set player2's name to user defaults
    [[NSUserDefaults standardUserDefaults] setValue:[textFieldTwo text] forKey:@"player2"];
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    [textField resignFirstResponder];
    return NO;
}
@end    

如果我在第二个IBAction中使用NSLog，一旦它完成，该数组将正确显示在控制台的字符串player1和player2中，但是，如果我试图在其他任何地方使用该数组，它是null。谁能给我指个正确的方向?

Answer 1

玩家有两个定义

1是一个属性。它从未初始化过，所以它是空的。你用它作为自我。玩家和实例变量_players.

One是一个实例变量。它在viewDidLoad中初始化。它不是nil

Answer 2

我会尝试将数组添加为私有实例变量，即将其添加到@interface中的.m文件中

NSMutableArray *players;

那么你应该能够通过使用"players"而不是self.players来访问数组。这应该在你的整个班级中都是可用的。如果这不起作用，那么我会说问题不在于你的变量的范围内，而是与其他一些代码。