PickerDelegate

z_xiaoyuan

于 2009-11-12 00:00:00 发布

阅读量518

点赞数

CC 4.0 BY-SA版权

分类专栏： iPhone 文章标签： uiview

本文链接：https://blog.youkuaiyun.com/z_xiaoyuan/article/details/4800526

iPhone 专栏收录该内容

6 篇文章

订阅专栏

本文详细介绍了UIPickerView的使用方法，包括数据源和代理的实现，以及如何通过代码配置组件和行数，设置选中项及重载组件等内容。通过示例展示了如何根据选择的状态更新数据。

UIPickerView

self has

Variable:

id<UIPickerViewDataSource> dataSource; id<UIPickerViewDelegate> delegate; BOOL showsSelectionIndicator NSInteger numberOfComponents;

Functions

- (NSInteger)numberOfRowsInComponent:(NSInteger)component; - (CGSize)rowSizeForComponent:(NSInteger)component; - (UIView *)viewForRow:(NSInteger)row forComponent:(NSInteger)component; - (void)reloadAllComponents; - (void)reloadComponent:(NSInteger)component; - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated; - (NSInteger)selectedRowInComponent:(NSInteger)component;

self has two @protocal

<UIPickerViewDataSource> @required - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView; - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component; <UIPickerViewDelegate> @optional - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component; - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component; - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component; - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view; - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;

IF you want use Picker in you app, you want to accomplish two delegates

for e.g

#pragma mark - #pragma mark Picker Data Source Methods - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 2; } - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { if (component == kStateComponent) return [self.states count]; return [self.zips count]; } #pragma mark Picker Delegate Methods - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { if (component == kStateComponent) return [self.states objectAtIndex:row]; return [self.zips objectAtIndex:row]; } - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component { return 40.0f; } - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component { if (component == kZipComponent) return 90; return 205; } - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { if (component == kStateComponent) { NSString *selectedState = [self.states objectAtIndex:row]; NSArray *array = [stateZips objectForKey:selectedState]; self.zips = array; [picker selectRow:0 inComponent:kZipComponent animated:YES]; [picker reloadComponent:kZipComponent]; } } - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view { if (component == 0) return [self.column1 objectAtIndex:row]; else if (component == 1) return [self.column2 objectAtIndex:row]; else if (component == 2) return [self.column3 objectAtIndex:row]; else if (component == 3) return [self.column4 objectAtIndex:row]; return [self.column5 objectAtIndex:row]; }