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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
 
[cpp] 
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。
 
[cpp]  
- (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。
 
[cpp]  
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
 
[cpp]  
- (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
 
[cpp]  
- (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。
 
[cpp] 
- (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。
补充:移动开发 , IOS ,
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