恢复文件文档基础应用程序
我的第一个基于文档的应用程序遇到了一些问题。很简单： 在 myDocument.m 上，我创建了一些方法
- (IBAction)salva:(id)sender {
[array addObject:@"Hello"];
[nomeLabel setStringValue:@"ciao"];
NSLog(@"%@",[array objectAtIndex:0]);
}
，用于在数组上保存值
- (BOOL) writeToURL:(NSURL *)url ofType:(NSString *)typeName error:(NSError **)outError {
return [array writeToURL:url atomically:YES];
}
，用于使用此方法将数组保存在文件上，
- (void) imposta {
[nomeLabel setStringValue:[array objectAtIndex:0]];
NSLog(@"Ciao");
}
我使用数组的内容设置标签的内容
- (BOOL) readFromURL:(NSURL *)url ofType:(NSString *)type error:(NSError **)outError{
[ array release];
array = [[NSMutableArray alloc] initWithContentsOfURL:url];
NSLog(@"%@",[array objectAtIndex:0]);
[self imposta];
return YES;
}
，用于加载文件。 问题是我无法使用加载数组的内容设置标签。该数组已加载，因为使用 NSLog 我看到了正确的值，问题是我无法将其放在上面
I have a little problem with my first document based application. Is very simple:
on myDocument.m I make some method
- (IBAction)salva:(id)sender {
[array addObject:@"Hello"];
[nomeLabel setStringValue:@"ciao"];
NSLog(@"%@",[array objectAtIndex:0]);
}
this for save a value on my array
- (BOOL) writeToURL:(NSURL *)url ofType:(NSString *)typeName error:(NSError **)outError {
return [array writeToURL:url atomically:YES];
}
this for save the array on a file
- (void) imposta {
[nomeLabel setStringValue:[array objectAtIndex:0]];
NSLog(@"Ciao");
}
with this method I set the content of a label with the content of array
- (BOOL) readFromURL:(NSURL *)url ofType:(NSString *)type error:(NSError **)outError{
[ array release];
array = [[NSMutableArray alloc] initWithContentsOfURL:url];
NSLog(@"%@",[array objectAtIndex:0]);
[self imposta];
return YES;
}
this for load the file.
The problem is that I can't set the label with the content of loaded array. The array wes loaded because with an NSLog I see the correct value, the problem is that I can't put it on th
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第一次打开文档时，会在实例化窗口控制器之前调用
-readFromURL:ofType:error:。这意味着您的 nameLabel 连接可能为零。您应该尽早在-awakeFromNib或-windowControllerDidLoadNib:中进行更新。但实际上，NSDocument 是一个模型对象，因此无论如何都不应该直接连接到视图对象。文档应该只存储其数据，窗口控制器应该负责更新视图。
When opening a document for the first time,
-readFromURL:ofType:error:is called before the window controllers are instantiated. That means your nameLabel connection is probably nil. You should update in-awakeFromNibor-windowControllerDidLoadNib:at the very earliest.But really, NSDocument is a model object and therefore shouldn't be connected directly to a view object anyway. The document should just be storing its data, and the window controller should be responsible for updating the view.