// 1.创建DatePicker

    UIDatePicker *datePicker = [[UIDatePicker alloc] init];

    // 2.设置模式

    [datePicker setDatePickerMode:UIDatePickerModeDate];

    // 3.设置locale

    [datePicker setLocale:[NSLocale localeWithLocaleIdentifier:@"zh_CN"]];

    // 4.设置textField的响应键盘为DatePicker

    [self.textField setInputView:datePicker];

// 1.创建UIToolBar

    UIToolbar *toolBar = [[UIToolbar alloc] init];

    toolBar.barTintColor = [UIColor grayColor]; // 这个才是UIToolBar的背景色

    toolBar.frame = CGRectMake(, , , ); // 必须设置好size，UIToolBar才能显示，否则只能显示Item，且不能点击

    // 2.创建Item

    UIBarButtonItem *item1 = [[UIBarButtonItem alloc] initWithTitle:@"上一个" style:UIBarButtonItemStylePlain target:self action:@selector(previousClicked)];

    UIBarButtonItem *item2 = [[UIBarButtonItem alloc] initWithTitle:@"下一个" style:UIBarButtonItemStylePlain target:self action:@selector(nextClicked)];

    UIBarButtonItem *item3 = [[UIBarButtonItem alloc] initWithTitle:@"完成" style:UIBarButtonItemStylePlain target:self action:@selector(finishClicked)];

    // 间隙Item

    UIBarButtonItem *spaceItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];

    // 3.添加Item到UIToolBar

    toolBar.items = @[item1, item2, spaceItem, item3];

    // 4.添加UIToolBar到键盘上方，设置为textField的辅助视图

    self.textField.inputAccessoryView = toolBar;