UIPickerView 详解

<UIPickerViewDataSource,UIPickerViewDelegate> 实现这二个协议
 1 UIPickerView *pv = [[UIPickerView alloc] init];
 2     pv.delegate = self;
 3     pv.dataSource = self;
 4     pv.showsSelectionIndicator = YES; // 是否显示选择标示
 5 
 6     -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
 7         return 3;   // 3 列
 8     }
 9     -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
10         return 10;  // 每列10行
11     }
12     -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
13         return [NSString stringWithFormat:@"%d-%d",row,component];  // 每条显示内容
14     }
15     -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
16         // 用户选择的内容
17     }
18     -(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{
19         return 10; // 行高
20     }
21     -(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component{
22         return 10; // 行宽
23     }