相关疑难解决方法(0)

我添加了我的编辑按钮

self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] 
        initWithBarButtonSystemItem:UIBarButtonSystemItemEdit target:self 
        action:@selector(editNavButtonPressed)] autorelease];

但我似乎无法将其转为完成和返回,控制台说它是Null

-(IBAction)editNavButtonPressed
{
//[self.tableView setEditing:YES animated:YES];
BOOL editing = !self.tableView.editing;
NSLog(@"tile=#%@#", self.navigationItem.rightBarButtonItem.title);

if ([self.navigationItem.rightBarButtonItem.title isEqualToString:NSLocalizedString(@"Edit", @"Edit")]) {
    self.navigationItem.rightBarButtonItem.title = NSLocalizedString(@"Done", @"Done");
} else {
    self.navigationItem.rightBarButtonItem.title = NSLocalizedString(@"Edit", @"Edit");

}
//self.navigationItem.rightBarButtonItem.enabled = !editing;
//self.navigationItem.rightBarButtonItem.title = (editing) ? NSLocalizedString(@"Done", @"Done") : NSLocalizedString(@"Edit", @"Edit");
[self.tableView setEditing: editing animated: YES];

}