代码没有起作用,该怎么解决_Iphone

代码没有起作用
代码：

C/C++ code

#pragma mark -#pragma mark UITextViewDelegate- (void)doneEditting:(id)sender {        [textViewContent resignFirstResponder];    self.navigationItem.rightBarButtonItem = nil;}- (void)textViewDidBeginEditing:(UITextView *)textView {        self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc]                                                initWithTitle:@"Done"                                                style:UIBarButtonItemStyleDone                                                target:self                                                action:@selector(doneEditting:)]                                                autorelease];}

没有在navigation bar上面添加一个文字为Done的按钮。
怎么回事呢？

------解决方案--------------------
你好~
系统自带《Done》按钮的~

UIBarButtonItem *aItme = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneEditting:)];
self.navigationItem.rightBarButtonItem = aItem;
[aItem release];

希望有所帮助