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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