UIPickerView(滚动选择控制器) · iOS UI

1.UIPickerView的宽度和高度是固定的,纵向是320*216,横向是568*162 2.属性: @property(nonatomic,readonly)NSInteger numberOfComponents; // 选择框的行数 @property(nonatomic,assign)idUIPickerViewDataSource> dataSource; (类似于UITableView) @property(nonatomic,assign)idUIPickerViewDelegate>delegate; (类似于UITableView) (BOOL)showsSelectionIndicator// 是否显示选择指示器 ,即是一个蓝色的条 ~~~ pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 0, 320, 216)]; // 指定Delegate pickerView.delegate=self; // 显示选中框 pickerView.showsSelectionIndicator=YES; [self.view addSubview:pickerView]; ~~~ 以上可以在视图显示一个选取器，但是内容空白，pickerView.showsSelectionIndicator=YES;是这只当前选取器所选中的内容：选取器上显示数据，必须依赖两个协议，UIPickerViewDelegate和UIPickerViewDataSource，把他们添加到ViewController.h文件中 ~~~ #import <UIKit/UIKit.h> @interface ViewController : UIViewController<UIPickerViewDelegate,UIPickerViewDataSource> { UIPickerView *pickerView; NSArray *pickerData; } @end ~~~ 3.然后在.m文件的ViewDidLoad中初始化界面 ~~~ - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 0, 320, 216)]; // 指定Delegate pickerView.delegate=self; // 显示选中框 pickerView.showsSelectionIndicator=YES; [self.view addSubview:pickerView]; NSArray *dataArray = [[NSArray alloc]initWithObjects:@"许嵩",@"周杰伦",@"梁静茹",@"许飞",@"凤凰传奇",@"阿杜",@"方大同",@"林俊杰",@"胡夏",@"邱永传", nil]; pickerData=dataArray; // 添加按钮 CGRect frame = CGRectMake(120, 250, 80, 40); UIButton *selectButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; selectButton.frame=frame; [selectButton setTitle:@"SELECT" forState:UIControlStateNormal]; [selectButton addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:selectButton]; } ~~~ 4.实现UIPickerView的代理方法，将数据显示在选取器上所需要几个方法 ~~~ #pragma mark - #pragma mark Picker Date Source Methods //返回显示的列数 -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 1; } //返回当前列显示的行数 -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { return [pickerData count]; } #pragma mark Picker Delegate Methods //返回当前行的内容,此处是将数组中数值添加到滚动的那个显示栏上 -(NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { return [pickerData objectAtIndex:row]; } ~~~ 前两个是数据源的代理方法，一个是返回列，有几个选取器就返回几，第二个是设置选取器有多少行，因为就这一个选取器，所以直接返回行数，即数组元素个数多少；第三个代理方法是将数组元素添加到了选取器上面显示；说一下两个协议实例方法,参考[http://www.cnblogs.com/edsioon/](http://www.cnblogs.com/edsioon/) UIPickerViewDelegate[中的实例方法](http://www.cnblogs.com/edsioon/archive/2012/03/27/2418914.html) // 当用户选择某个row时 - (void) pickerView: (UIPickerView *)pickerView didSelectRow: (NSInteger)row inComponent: (NSInteger)component // 当其在绘制row内容,需要row的高度时 - (CGFloat) pickerView:(UIPickerView *)pickerView rowHeightForComponent: (NSInteger) component // 返回指定component.row显示的文本 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger) component // 当picker view需要给指定的component.row指定view时,调用此函数.返回值为用作row内容的view - (UIView *)pickerView: (UIPickerView *)pickerView view ForRow:(NSInteger) row forComponent:(NSInteger) component reusingView:(UIView *) view // row的宽度 - (CGFloat)pickerView: (UIPickerView *)pickerView widthForComponent:(NSInteger) component [UIPickerViewDataSource](http://www.cnblogs.com/edsioon/archive/2012/03/27/2418919.html)[中的实例方法](http://www.cnblogs.com/edsioon/archive/2012/03/27/2418919.html) 按照官方文档的说法,UIPickerViewDataSource这个协议仅有的功能就是提供picker view中component的个数和各个component中的row的个数,虽然名为datasource,但是它工作于MVC的C中本协议仅有两个实例方法,均需要实现: // 返回列数 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView // 返回每一列对应的行数 - (NSInteger) pickerView:(UIPickerView *) pickerView numberOfRowsInComponent:(NSInteger) component 5.关于按钮响应事件，关于按钮的形成和添加响应事件不再提，前面都有， ~~~ (void) buttonPressed:(id)sender { NSInteger row =[pickerView selectedRowInComponent:0]; NSString *selected = [pickerData objectAtIndex:row]; NSString *message = [[NSString alloc] initWithFormat:@"你选择的是:%@",selected]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:message delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; } ~~~ @UIPickerView还有其他实例方法 // 获取指定列的行数 - (NSInteger) numberOfRowsInComponent:(NSInteger)component // 刷新所有的列 - (void) reloadAllComponents // 刷新指定的列 - (void) reloadComponent: (NSInteger) component - (CGSize) rowSizeForComponent: (NSInteger) component // 获取某列选择的行数 - (NSInteger) selectedRowInComponent: (NSInteger) component // 选择一行 - (void) selectRow: (NSInteger)row inComponent: (NSInteger)component animated: (BOOL)animated - (UIView *) viewForRow: (NSInteger)row forComponent: (NSInteger)component 附上源代码: [http://download.csdn.net/detail/duxinfeng2010/4410909](http://download.csdn.net/detail/duxinfeng2010/4410909)