Question

我有问题。我尝试在xib文件中创建的classViewController中初始化变量。我尝试使用下面的代码，但是当我将一个对象附加到数组时，这些数组未初始化。你能帮助我吗？谢谢，抱歉我的英语。

#import <UIKit/UIKit.h>

@interface AccelerometroViewController : UIViewController <UIAccelerometerDelegate, UITextFieldDelegate, UIAlertViewDelegate>{

    //.....     

    NSMutableArray *arrayPosizioni;
    NSMutableArray *arrayPosizioniCorrenti;

    NSString *nomePosizioneCorrente;

}

-(IBAction)salvaPosizione;


//...
@property (nonatomic, assign)   NSMutableArray      *arrayPosizioni;
@property (nonatomic, assign)   NSMutableArray      *arrayPosizioniCorrenti;

@property (nonatomic, assign)   NSString      *nomePosizioneCorrente;

@end



#import "AccelerometroViewController.h"
#import "Position.h"

@implementation AccelerometroViewController



float actualX;
float actualY;
float actualZ;


@synthesize arrayPosition;
@synthesize arrayCurrentPosition;

@synthesize nameCurrentPosition;

    -(id)init {
        self = [super init];
        if (self != nil) {
            arrayPosition = [[NSMutableArray alloc]init];
            arrayCurrentPosition = [[NSMutableArray alloc]init];
            nameCurrentPosition = [NSString stringWithFormat:@"noPosition"]; 
            actualX = 0;
            actualY = 0;
            actualZ = 0;
        }
        return self;
    }


    -(void)updateTextView:(NSString*)nomePosizione
    {
        NSString *string = [NSString stringWithFormat:@"%@", nameCurrentPosition];
        textEvent.text = [textEvent.text        stringByAppendingString:@"\n"];
        textEvent.text = [textEvent.text        stringByAppendingString:string];
    }


    -(IBAction)savePosition{

        Posizione *newPosition;
        newPosition = [[Position alloc]init];

        if([newPosition     setValue:(NSString*)fieldNomePosizione.text:(float)actualX:(float)actualY:(float)actualZ]){
       //setValue is a method of Position. I'm sure that this method is correct
            UIAlertView *alert = [[UIAlertView  alloc] initWithTitle:@"Salvataggio Posizione" message:@"Posizione salvata con successo" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
            [alert  show];
            [alert  release];           
            [arrayPosition  addObject:newPosition];
        }
        else{
            UIAlertView *alert = [[UIAlertView  alloc] initWithTitle:@"Salvataggio osizione" message:@"Errore nel salvataggio" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
            [alert show];
            [alert release];
        }
   }

 - (void) initialise {
     arrayPosition = [[NSMutableArray alloc] init];
     arrayCurrentPosition = [[NSMutableArray alloc] init];
     nameCurrentPosition = @"noPosition"; 
     actualX = 0;
     actualY = 0;
     actualZ = 0;
 }

 - (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle {
     if (self = [super initWithNibName:nibName bundle:bundle]) {
         [self initialise];
     }
}

Answer 1

除了Felix关于错误命名的评论之外，你的属性也是错误的。需要保留或复制对象，而不是分配对象（在大多数情况下），这样您就可以确定它们的价值不会消失。你需要拥有它们。因此我会使用以下内容：

@property (nonatomic, readwrite, retain)   NSMutableArray *arrayPosition;
@property (nonatomic, readwrite, retain)   NSMutableArray *arrayCurrentPosition;
@property (nonatomic, readwrite, copy)   NSString *nameCurrentPosition;

然后，因为你保留了一些东西，你负责释放它。因此，你需要一个dealloc方法来做到这一点。

-(void)dealloc {
    self.arrayPosition = nil;
    self.arrayCurrentPosition = nil;
    self.nameCurrentPosition = nil;
    [super dealloc];
}

使用nibFIle初始化失败

1 个答案: