無法從基於選擇的UIPickerView中刪除項目

Question

因此，只要輸入不是「NULL」，我就有一個UIPicker視圖，它從NSMutableArray中填充。

所以我的選擇器顯示除NULL以外的所有值。

現在，我有一個UITextField框和一個按鈕。所以，無論我在文本字段中輸入什麼內容，並且單擊該按鈕，如果它與NSMutableArray（用於填充UIPickerView）中的任何內容相匹配，它將其設置爲NULL並刷新UIPicker，使其不會再次顯示。

出於某種原因，我可以將值設置爲NULL（使用NSLog進行檢查），但選擇器永遠不會更新，NSMutable Array也不會。

-(void) loadthepicker 
{ 

    NSMutableArray *getarray = [NSMutableArray arrayWithArray:[[NSUserDefaults standardUserDefaults] objectForKey:@"FilerNamesArray"]]; 


    pickerLoaderArray=[[NSMutableArray alloc] init]; 



    for (int j=0; j<20; j++) { 



     if ([[getarray objectAtIndex:j] isEqualToString:@"NULL"]) 
     { 
      // do nothing..don't load 


     } 
     else // add that filter to pickerLoaderArray 
     { 

      [pickerLoaderArray addObject:[getarray objectAtIndex:j]]; 



     } 



    } // end of for 




    [pickerView reloadAllComponents]; 

    [pickerView selectRow:0 inComponent:0 animated:NO]; 

} 

-(NSInteger)numberOfComponentsInPickerView:(NSInteger)component 
{ 
    return 1; 
} 

-(NSInteger)pickerView:(UIPickerView *)picker numberOfRowsInComponent:(NSInteger)component 
{ 

    return [pickerLoaderArray count]; 

} 

-(NSString *)pickerView:(UIPickerView *)picker titleForRow:(NSInteger)row forComponent:(NSInteger)component{ 

    return [pickerLoaderArray objectAtIndex:row]; 
    } 

按鈕：

- (IBAction)deleteButton:(id)sender { 

    NSUserDefaults *CheckFiltersUsed = [NSUserDefaults standardUserDefaults]; 
    NSInteger myInt = [CheckFiltersUsed integerForKey:@"FiltersUsed"]; 

    if (myInt<=20 && myInt>0) { 


     NSLog(@"number of filters used before deleting %ld",(long)myInt); 
     [CheckFiltersUsed setInteger:myInt-1 forKey:@"FiltersUsed"]; 
     [CheckFiltersUsed synchronize]; 

     // get names array 
     NSMutableArray *getarray = [NSMutableArray arrayWithArray:[[NSUserDefaults standardUserDefaults] objectForKey:@"FilerNamesArray"]]; 
     NSArray *get=getarray; 


     // at location where name matches with selectedfilter..put NULL 
     for (int j=0; j<20; j++) { 

      if ( [[getarray objectAtIndex:j] isEqualToString:_filterToDelete.text] && isFilterDeleted==NO) 
      { 

       NSLog(@"------currently %d is %@",j,[getarray objectAtIndex:j]); 
       [getarray insertObject:@"NULL" atIndex:j]; 
       NSLog(@"------now %d is %@",j,[getarray objectAtIndex:j]); 

       UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"" message: @"Deleted" delegate: nil cancelButtonTitle:@"Ok" otherButtonTitles:nil]; [alert show]; 

       isFilterDeleted=YES; 

       [[NSUserDefaults standardUserDefaults] setObject:getarray forKey:@"FilerNamesArray"]; 
       [[NSUserDefaults standardUserDefaults]synchronize]; 

       [self loadthepicker]; 

      } 

      else 
      { 


       NSLog(@"No matching filter name"); 

      } 


     } // end of for 

     //now save this array back. 


    } 

    else 
    { 

     NSUserDefaults *CheckFiltersUsed = [NSUserDefaults standardUserDefaults]; 
     NSInteger myInt = [CheckFiltersUsed integerForKey:@"FiltersUsed"]; 
     NSLog(@"Wrong number of filters!!!... %d",myInt); 

    } 

} 

Answer 1

如果我得到你正在嘗試做的，你想從陣列中刪除和選擇器平等的字符串爲好。但不是你剛剛插入其它的NSString對象爲索引 'J'

在deleteButton方法：

代替此行的

[getarray insertObject:@"NULL" atIndex:j]; 

呼叫

[getarray removeObjectAtIndex:j]; 

**更新

在loadPicker中刪除if語句來檢查是否E弦等於@ 「NULL」

所以不是：

for (int j=0; j<20; j++) { 
    if ([[getarray objectAtIndex:j] isEqualToString:@"NULL"]) 
    { 
     // do nothing..don't load 
    } 
    else // add that filter to pickerLoaderArray 
    { 
     [pickerLoaderArray addObject:[getarray objectAtIndex:j]]; 
    } 
} 

務必：

for(NSString *pickerValue in getarray){ 
    [pickerLoaderArray addObject:pickerValue]; 
}