UIPikerView的属性1.numberOfComponents：返回UIPickerView当前的列数NSIntegernum=_pickerView.numberOfComponents;NSLog(@"%d",num);2.-(NSInteger)numberOfRowsInComponent:(NSInteger)component;返回component列中有多少行。NSIntegernumInCp=[_pickerViewnumberOfRowsInComponent:0];NSLog(@"%d",numInCp);3.-(CGSize)rowSizeForComponent:(NSInteger)component;返回component中一行的尺寸。CGSizesize=[_pickerViewrowSizeForComponent:0];NSLog(@"%@",NSStringFromCGSize(size));2.delegate：2.0设置UIPickerView代理_pickerView.delegate=self;//设置UIPickView每行显示的内容2.1-(NSString*)pickerView:(UIPickerView*)pickerViewtitleForRow:(NSInteger)rowforComponent:(NSInteger)component{return@"showData";}2.2-(UIView*)pickerView:(UIPickerView*)pickerViewviewForRow:(NSInteger)rowforComponent:(NSInteger)componentreusingView:(UIView*)view;//返回一个视图，用来设置pickerView的每行显示的内容。-(UIView*)pickerView:(UIPickerView*)pickerViewviewForRow:(NSInteger)rowforComponent:(NSInteger)componentreusingView:(UIView*)view{UIView*myView=[[UIViewalloc]init];myView.backgroundColor=[UIColorredColor];returnmyView;}效果：3.dataSource：数据源#pragmamark-dataSourcemethod//设置每列显示3行-(NSInteger)pickerView:(UIPickerView*)pickerViewnumberOfRowsInComponent:(NSInteger)component{return3;}//设置显示2列-(NSInteger)numberOfComponentsInPickerView:(UIPickerView*)pickerView{return2;}4.showsSelectionIndicator：是否显示指示器，默认为NO_pickerView.showsSelectionIndicator=NO;注意：设置UIPickerView的行数与列数需要设置数据源，遵守UIPickerViewDataSource，设置UIPickerView的内容需要设置代理，并且遵守代理方法UIPickerViewDelegate。5.-(void)pickerView:(UIPickerView*)pickerViewdidSelectRow:(NSInteger)rowinComponent:(NSInteger)component;当点击UIPickerView的某一列中某一行的时候，就会调用这个方法。6.返回第component列每一行的高度-(CGFloat)pickerView:(UIPickerView*)pickerViewrowHeightForComponent:(NSInteger)component;7.刷新某一列的数据一旦调用了这个方法，就会重新给数据源发送消息计算这列的行数、重新给代理发送消息获得这列的内容[pickerViewreloadComponent:1];8.刷新所有列的数据-(void)reloadAllComponents;9.返回选中的是第component列的第几行。-(NSInteger)selectedRowInComponent:(NSInteger)component;
