pickerView

一.UIPickerViewDataSource

// 返回有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;

// 返回第component有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;

二.UIPickerViewDelegate

// 返回第component列多宽
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component

// 返回第component列多高
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component

// 返回第component列第row行标题
- (NSString )pickerView:(UIPickerView )pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component

// NSAttributedString:富文本,可以描述文本的外观属性,颜色,字体,阴影,空心,图文混排
- (NSAttributedString )pickerView:(UIPickerView )pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component

// 返回第component列第row行视图控件
- (UIView )pickerView:(UIPickerView )pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view

// 当用户选中某一行的时候调用 
// 选中第component列第row行的时候调用 
// 可以监听pickerView滚动
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component