IOS中的各种Picker

简述

在应用的一些设置中经常要用到一些Picker来快速帮助用户选定取值，一般会用到的有UIDatePicker，UIPickerView以及UIImagePickerController。

初始界面

如图，在搭建好的界面，实现方法来完成各个选择。首先是日期选择

UIDatePicker

主要需要设置的属性有

locale

datePickerMode

    UIDatePicker *datePicker = [[UIDatePicker alloc] init];    datePicker.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_Hans_cn"];    datePicker.datePickerMode = UIDatePickerModeDate;        NSString *stdDate = @"1990-01-01";    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];    formatter.dateFormat = @"yyyy-MM-dd";    [datePicker setDate:[formatter dateFromString:stdDate] animated:YES];    [datePicker addTarget:self action:@selector(showDate:) forControlEvents:UIControlEventValueChanged];        _dateField.inputView = datePicker;    _dateField.text = stdDate;

在这里，我们也对它的初始日期进行了设置。

对齐事件进行监听即可达到目的，并没有代理协议。

- (void)showDate:(UIDatePicker *)datePicker{    NSDate *date = datePicker.date;    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];    formatter.dateFormat = @"yyyy-MM-dd";    NSString *outputString = [formatter stringFromDate:date];        _dateField.text = outputString;}

UIImagePickerController

如果不自定义选取照片视图的话，实现照片或者拍照选取功能十分简单，设置协议就可以快速调用。

    UIImagePickerController *imagePC = [[UIImagePickerController alloc] init];    //从照片库中选择图片， 也可以设置相机    imagePC.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;    //允许对图片进行简单的编辑    imagePC.allowsEditing = YES;    imagePC.delegate = self;    [self presentViewController:imagePC animated:YES completion:nil];

协议方法获取图片并进行设置

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{    const NSString *REditedImageIdentifier = @"UIImagePickerControllerEditedImage";        UIImage *image = info[REditedImageIdentifier];    [_imageButton setImage:image forState:UIControlStateNormal];        [picker dismissViewControllerAnimated:YES completion:nil];}

UIPickerView

在Component较多的时候，PickerView稍微要复杂一些。首先初始化和设置属性

- (void)pickerViewAndMethod{    UIPickerView *pickerView = [[UIPickerView alloc] init];    pickerView.delegate = self;    pickerView.dataSource = self;    //显示选择活动器    pickerView.showsSelectionIndicator = YES;    _cityField.inputView = pickerView;    _cityField.text = @"北京 - 海淀";}

实现数据源和代理方法，来刷新自身数据和界面。

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{    return rComponentCount;}- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{    if (component == rProvinceComponent)    {        return _cityList.count;    }    else    {        NSInteger i = [pickerView selectedRowInComponent:rProvinceComponent];        NSArray *arr = _cityList[i][@"city"];        return arr.count;    }}- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    if (component == rProvinceComponent)    {        NSString *proName = _cityList[row][@"province"];        return proName;    }    else    {        NSInteger i = [pickerView selectedRowInComponent:rProvinceComponent];        NSString *cityName = _cityList[i][@"city"][row];        return cityName;    }}- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{    [pickerView reloadComponent:rCityComponent];        NSInteger proIndex = [pickerView selectedRowInComponent:rProvinceComponent];    NSString *proName = _cityList[proIndex][@"province"];        NSInteger cityIndex = [pickerView selectedRowInComponent:rCityComponent];    NSString *cityName = _cityList[proIndex][@"city"][cityIndex];        _cityField.text = [NSString stringWithFormat:@"%@ - %@", proName, cityName];}

数据源来自于自己写的一个简单的Plist文件。一个数组中包含多个字典。

这样一个使用各种Picker进行设置的功能就完成了。

demo示例点击打开链接

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