執行錯誤訪問NSString

Question

individualPercUpdated被調用UIControlEventEditingDidEnd而checkInitialValue被調用UIControlEventEditingDidBegin。通過給予警告Exec的錯誤訪問

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    initialValue=[[NSString alloc] init]; 
} 

-(void) individualPercUpdated:(UITextField *)textField{ 

    if(initialValue!=nil){ 
     if(!([initialValue isEqualToString:textField.text])){ 
      initialValue=textField.text; 
      NSLog(@"%@",textField.text); 
     } 
    } 

    else{ 
     NSLog(@"%@",textField.text); 
    } 
} 

-(void) checkInitialValue:(UITextField *)textField{ 
     initialValue=textField.text; 
    } 

} 

Answer 1

更換無處不在一行if(!([initialValue isEqualToString:textField.text]))我PROG崩潰您使用實例變量財產和獲得它，雖然它，你不會有內存管理的任何問題。

@property (nonatomic, copy) NSString *initialValue; 
... 
@synthesize initialValue = _initialValue; 
.... 
//Access with: 
self.initialValue = @"something";