如何设置 ABPeoplePickerNavigationController 的提示？

这是我用来调用人员选择器的代码，但提示标签文本不会更改：

ABPeoplePickerNavigationController *picker = [[ABPeoplePickerNavigationController alloc] init];
picker.peoplePickerDelegate = self;
picker.displayedProperties = [NSArray arrayWithObjects: [NSNumber numberWithInt:kABPersonEmailProperty], nil];  

picker.navigationItem.prompt = @"Choose a contact to...";

[self presentModalViewController:picker animated:YES];

其他答案中缺少一条关键信息，而且不是很明显。您需要设置提示after该行：

[self presentModalViewController:picker animated:YES];

所以，如果你这样做，它会起作用：

[self presentModalViewController:picker animated:YES];
picker.navigationBar.topItem.prompt = @"Choose a contact to...";