PickeView常用

```objc#pragma mark - 数据源,以下为@required的方法// 返回pickerView有多少列- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{     NSLog(@"numberOfComponentsInPickerView");    return 3;}// 返回第component列有多少行- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{    NSLog(@"numberOfRowsInComponent");    return 2;}#pragma mark - 代理// 返回第component列的每一行的行高- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{    return 80.0;}// 返回第component列第row行的标题- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    NSLog(@"-----%zd",[pickerView selectedRowInComponent:component]);    NSLog(@"titleForRow");    return @"a";}// NSAttributedString富文本属性: 可以描述文字大小和颜色//- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component NS_AVAILABLE_IOS(6_0)// 总结：如果同时实现返回字符串和view的方法，返回UIView的优先级比较高// 返回第component列第row行的View- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{    UIView *vw = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 60)];    vw.backgroundColor = [UIColor redColor];    return vw;}// 选中第component第row的时候调用// __func__： 返回当前方法在哪个类里面调用- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{    NSLog(@"%s---%ld-%ld",__func__,component,row);    NSLog(@"%zd",[pickerView selectedRowInComponent:component]);}@end

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