我是Objective C的新手，我有一个问题。我创建了一个警报视图并在其中有一个文本字段，因此当用户尝试输入名称时，他/她可以使用名为他/她为文件名输入的标签。当用户点击按钮说明＆＃34; new＆＃34;将出现一个警告，其中包含一个文本框，提示用户输入文件的名称。一旦他们完成了这个，按钮说明＆＃34; new＆＃34;将被隐藏，并且标明他们输入的文本的标签将取消隐藏。如果他们觉得他们不再需要该文件，他们可以选择删除它。当他们单击删除按钮时，会出现一个警告，询问他们是否要使用两个按钮删除文件：是和否，但如果他们单击是，则会导致应用程序崩溃。请帮忙。
这是我的头文件：
#import <UIKit/UIKit.h>
NSString *File0Name;
NSString *File1Name;
NSString *File2Name;
NSString *File3Name;
int file;
int delet;
@interface Load : UIViewController <UIAlertViewDelegate>
{
IBOutlet UIButton *File1;
IBOutlet UIButton *File2;
IBOutlet UIButton *File3;
IBOutlet UIButton *DeleteFile1;
IBOutlet UIButton *DeleteFile2;
IBOutlet UIButton *DeleteFile3;
IBOutlet UILabel *File1Label;
IBOutlet UILabel *File2Label;
IBOutlet UILabel *File3Label;
}
-(IBAction)File1:(id)sender;
-(IBAction)File2:(id)sender;
-(IBAction)File3:(id)sender;
-(IBAction)DeleteFile1:(id)sender;
-(IBAction)DeleteFile2:(id)sender;
-(IBAction)DeleteFile3:(id)sender;
@end
这是我的实施文件：
-(IBAction)DeleteFile1:(id)sender{
NSString *delete1 = [NSString stringWithFormat:@"Are you sure you would like to delete %@", File1Name];
UIAlertView *Delete1 = [[UIAlertView alloc] initWithTitle:@"Delete File" message:delete1 delegate:self cancelButtonTitle:@"Yes" otherButtonTitles:@"No", nil];
[Delete1 show];
delet = 1; //This is sortive like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(IBAction)DeleteFile2:(id)sender{
NSString *delete2 = [NSString stringWithFormat:@"Are you sure you would like to delete %@", File2Name];
UIAlertView *Delete2 = [[UIAlertView alloc] initWithTitle:@"Delete File" message:delete2 delegate:self cancelButtonTitle:@"Yes" otherButtonTitles:@"No", nil];
[Delete2 show];
delet = 2; //This is sortive like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(IBAction)DeleteFile3:(id)sender{
NSString *delete3 = [NSString stringWithFormat:@"Are you sure you would like to delete %@", File3Name];
UIAlertView *Delete3 = [[UIAlertView alloc] initWithTitle:@"Delete File" message:delete3 delegate:self cancelButtonTitle:@"Yes" otherButtonTitles:@"No", nil];
[Delete3 show];
delet = 3; //This is like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(IBAction)File1:(id)sender{
UIAlertView *Alert1 = [[UIAlertView alloc] initWithTitle:@"Name this file!" message:@"Enter a name for this new file." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];
Alert1.alertViewStyle = UIAlertViewStylePlainTextInput;
[Alert1 show];
file = 1; //This is also like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(IBAction)File2:(id)sender{
UIAlertView *Alert2 = [[UIAlertView alloc] initWithTitle:@"Name this file!" message:@"Enter a name for this new file." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];
Alert2.alertViewStyle = UIAlertViewStylePlainTextInput;
[Alert2 show];
file = 2; //This is also like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(IBAction)File3:(id)sender{
UIAlertView *Alert3 = [[UIAlertView alloc] initWithTitle:@"Name this file!" message:@"Enter a name for this new file." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];
Alert3.alertViewStyle = UIAlertViewStylePlainTextInput;
[Alert3 show];
file = 3; //This is also like a tag so when I specify which button was clicked I can also specify which alert it is for
}
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex: (NSInteger)buttonIndex{
if ((buttonIndex == 0) && (file == 1)) {
File1Name = [[alertView textFieldAtIndex:0] text];
File1Label.text = File1Name;
File1.hidden = YES;
File1Label.hidden = NO;
DeleteFile1.hidden = NO;
NSLog(@"%@", File1Label.text);
}
if ((buttonIndex == 0) && (file == 2)) {
File2Name = [[alertView textFieldAtIndex:0] text];
File2Label.text = File2Name;
File2.hidden = YES;
File2Label.hidden = NO;
DeleteFile2.hidden = NO;
NSLog(@"%@", File2Label.text);
}
if ((buttonIndex == 0) && (file == 3)) {
File3Name = [[alertView textFieldAtIndex:0] text];
File3Label.text = File3Name;
File3.hidden = YES;
File3Label.hidden = NO;
DeleteFile3.hidden = NO;
NSLog(@"%@", File3Label.text);
}
if ((buttonIndex == 0) && (file == 1)) {
File1Name = [[alertView textFieldAtIndex:0] text];
File1Label.text = File1Name;
File1.hidden = YES;
File1Label.hidden = NO;
DeleteFile1.hidden = NO;
NSLog(@"%i", File1.hidden);
NSLog(@"%i", File1Label.hidden);
}
if ((buttonIndex == 0) && (delet == 1)) {
File1Label.hidden = YES;
File1Label.text = @"Label";
File1.hidden = NO;
DeleteFile1.hidden = YES;
}
if ((buttonIndex == 0) && (delet == 2)) {
File2Label.hidden = YES;
File2Label.text = @"Label";
File2.hidden = NO;
DeleteFile2.hidden = YES;
}
if ((buttonIndex == 0) && (delet == 3)) {
File3Label.hidden = YES;
File3Label.text = @"Label";
File3.hidden = NO;
DeleteFile3.hidden = YES;
}
}
- (void)viewDidLoad
{
DeleteFile1.hidden = YES;
DeleteFile2.hidden = YES;
DeleteFile3.hidden = YES;
File1.hidden = NO;
File1Label.hidden = YES;
File2.hidden = NO;
File2Label.hidden = YES;
File3.hidden = NO;
File3Label.hidden = YES;
[super viewDidLoad];
// Do any additional setup after loading the view.
}
@end
万一你想知道我拿出了其他方法，比如＆＃34;确实收到了内存警告＆＃34;这里不会这么长，但在我真正的 .m 文件中，我有它们。
如果这有帮助，以下是调试器控制台中显示的内容：
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'textFieldIndex (0) is outside of the bounds of the array of text fields'
*** First throw call stack:
(
0 CoreFoundation 0x0185b1e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x015da8e5 objc_exception_throw + 44
2 CoreFoundation 0x0185afbb +[NSException raise:format:] + 139
3 UIKit 0x007af61d -[UIAlertView textFieldAtIndex:] + 97
4 Balloon Assault 0x00003700 -[Load alertView:clickedButtonAtIndex:] + 144
5 UIKit 0x007a9733 -[UIAlertView modalItem:tappedButtonAtIndex:] + 67
6 UIKit 0x0087bac5 -[_UIModalItemsCoordinator _notifyDelegateModalItem:tappedButtonAtIndex:] + 180
7 UIKit 0x003b01c8 -[_UIModalItemAlertContentView tableView:didSelectRowAtIndexPath:] + 1035
8 UIKit 0x003849a1 -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1513
9 UIKit 0x00384b14 -[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 279
10 UIKit 0x0038910e __38-[UITableView touchesEnded:withEvent:]_block_invoke + 43
11 UIKit 0x002b80aa ___afterCACommitHandler_block_invoke + 15
12 UIKit 0x002b8055 _applyBlockToCFArrayCopiedToStack + 403
13 UIKit 0x002b7e76 _afterCACommitHandler + 532
14 CoreFoundation 0x0182336e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
15 CoreFoundation 0x018232bf __CFRunLoopDoObservers + 399
16 CoreFoundation 0x01801254 __CFRunLoopRun + 1076
17 CoreFoundation 0x018009d3 CFRunLoopRunSpecific + 467
18 CoreFoundation 0x018007eb CFRunLoopRunInMode + 123
19 GraphicsServices 0x0218e5ee GSEventRunModal + 192
20 GraphicsServices 0x0218e42b GSEventRun + 104
21 UIKit 0x0029af9b UIApplicationMain + 1225
22 Balloon Assault 0x0000488d main + 141
23 libdyld.dylib 0x0268e701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
答案 0 :(得分：1)
你正在崩溃，因为你说的是，例如，
File1Name = [[alertView textFieldAtIndex:0] text];
但您的提醒视图没有文字字段。看看如何创建警报视图。你是说，例如：
[[UIAlertView alloc] initWithTitle:@"Delete File" message:delete1 delegate:self cancelButtonTitle:@"Yes" otherButtonTitles:@"No", nil];
该警报视图中没有文本字段，您没有在那里放置文本字段。对于某些提醒视图，您要将alertViewStyle设置为UIAlertViewStylePlainTextInput，它会为您提供一个文本字段。但对于其他人，你不是。因此，当您的代理代码遇到没有代码的警报视图时，您就会崩溃。
显然，您在委托方法中决定要响应哪个警报视图的技术无法正常工作。这并不奇怪，因为您并未在每种情况下同时设置file和delet。但无论如何，这是一个糟糕的主意，因为警报视图是一回事，而Load对象中的实例变量则是另一回事。这是从一开始就做出这种区分的坏方法。
你对这种技术的评论说＆＃34;这就像一个标签＆＃34;。但它的不是就像一个标签。标签属于到警报视图（或其中的某些内容）。
区分哪个警报视图的方法是查看关于警报视图本身的 。例如，请求alertViewStyle！这将告诉您它是否有任何文本字段。