包括一個If語句的單個選擇器 - 不工作

Question

我有一個選擇器，我想要合併一個if語句，以便根據返回的文本顯示會有所不同，在執行此操作時出現了一些問題，代碼如下：

@implementation ButtonFive 

@synthesize singlePicker; 
@synthesize pickerData; 

-(IBAction)buttonPressed { 
NSInteger row = [singlePicker selectedRowInComponent:0]; 
NSString *selected = [pickerData objectAtIndex:row]; 




if ([selected isEqualToString: @"MC860"]) 
    //if ([selected isEqualToString: @"MC860"]) 
{ 
NSString *title = [[NSString alloc] initWithFormat: @"Use the maintenance utility to upgrade the %@!", selected]; 

} 

else { 
NSString *title = [[NSString alloc] initWithFormat: @"try this %@!", selected]; 

} 



//NSString *title = [[NSString alloc] initWithFormat: @"you selected %@!", selected]; 


UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message : @"Thank you for choosing." delegate:nil cancelButtonTitle :@"Continue" otherButtonTitles :nil]; 
[alert show]; 
[alert release]; 
[title release]; 
} 


- (void)viewDidLoad { 
NSArray *array = [[NSArray alloc]  initWithObjects:@"B410",@"B411",@"B440",@"B840",@"MC860", @"MC861",@"MC861",@"B410",@"B411",@"B440",@"B840",@"MC860", nil]; 
self.pickerData = array; 
[array release]; 
[super viewDidLoad]; 
} 

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView 
{ 
     return 1; 
} 

-(NSInteger)pickerView:(UIPickerView *)pickerView 
numberOfRowsInComponent:(NSInteger)component 
{ 
return [pickerData count]; 
} 

-(NSString *)pickerView:(UIPickerView *)pickerView 
     titleForRow:(NSInteger)row 
     forComponent:(NSInteger)component 
{ 
return[pickerData objectAtIndex:row]; 
} 

標題文本無法識別，但我想我可能會對此全部錯誤，任何幫助都非常感謝。

Answer 1

你應該得到編譯錯誤..原因很明顯......你在if和else塊中聲明瞭標題，但你應該在if-else塊之前聲明它！

即。你應該使用這個代碼代替你的 -

NSString *title; 


if ([selected isEqualToString:@"MC860"])//if ([selected isEqualToString: @"MC860"]) 
{ 
    title = [[NSString alloc] initWithFormat:@"Use the maintenance utility to upgrade the %@!", selected]; 
} 
else { 
    title = [[NSString alloc] initWithFormat:@"try this %@!", selected]; 

}