IOS_OC UIPickerView

UIPickerView 类似于UITableView和UICollectionView

首先实现

// 返回pickerView有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{ return 3;}
// 返回第component列有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{ return 2;}
#pragma mark - 代理
// 返回第component列的每一行的行高
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{ return 80.0;}
// 返回第component列第row行的标题
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{ return @"a";}
//NSAttributedString富文本属性: 可以描述文字大小和颜色
- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component NS_AVAILABLE_IOS(6_0); // attributed title is favored if both methods are implemented
// 总结：如果同时实现返回字符串和view的方法，返回UIView的优先级比较高
// 返回第component列第row行的View
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{ UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 60)]; v.backgroundColor = [UIColor redColor]; return v;}
// 选中第component第row的时候调用// __func__： 返回当前方法在哪个类里面调用
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{ NSLog(@"%s---%ld-%ld",__func__,component,row);
}

使用UIPickerView时一般需要自定义键盘

#pragma mark - UITextFieldDelegate
// 是否允许开始编辑
//- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField//{// return NO;//}
// 是否允许结束编辑
//- (BOOL)textFieldShouldEndEditing:(UITextField *)textField//{// return NO;//}

// 是否允许用户输入文字
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ 
return NO;
}
// 文本框开始编辑的时候调用
- (void)textFieldDidBeginEditing:(UITextField *)textField{
 // 给生日文本框赋值
 [self dateChange:_datePicker];
}
- (void)viewDidLoad { [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib. _birthdayField.delegate = self;
 // 自定义生日键盘
 [self setUpBirthdayKeyboard];
}
// 自定义生日键盘
- (void)setUpBirthdayKeyboard{ 
// 创建UIDatePicker // 注意：UIDatePicker有默认的尺寸，可以不用设置frame UIDatePicker *picker = [[UIDatePicker alloc] init]; 
_datePicker = picker; 
// 设置地区 zh:中国
 picker.locale = [NSLocale localeWithLocaleIdentifier:@"zh"]; 
// 设置日期的模式 
picker.datePickerMode = UIDatePickerModeDate;
 // 监听UIDatePicker的滚动
 [picker addTarget:self action:@selector(dateChange:) forControlEvents:UIControlEventValueChanged]; 
_birthdayField.inputView = picker;
}
// 当UIDatePicker滚动的时候调用
// 给生日文本框赋值
- (void)dateChange:(UIDatePicker *)datePicker{
 NSLog(@"%@",datePicker.date);
 // 日期转换字符串 
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
 fmt.dateFormat = @"yyyy-MM-dd"; 
NSString *dateStr = [fmt stringFromDate:datePicker.date]; 
_birthdayField.text = dateStr;
}
- (void)didReceiveMemoryWarning { 
[super didReceiveMemoryWarning]; 
// Dispose of any resources that can be recreated.
}