Pickers包含一个旋转的可滚动视图,该视图用于从项目列表中选择一个值。
- (void)reloadAllComponents - (void)reloadComponent:(NSInteger)component - (NSInteger)selectedRowInComponent:(NSInteger)component - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated
无涯教程将为文本字段,选项器视图和数组添加。无涯教程将采用 UITextFieldDelegate,UIPickerViewDataSource 和 UIPickerViewDelegate 协议。
ViewController.h 如下-
#import <UIKit/UIKit.h> @interface ViewController : UIViewController <UITextFieldDelegate, UIPickerViewDataSource, UIPickerViewDelegate> { UITextField *myTextField; UIPickerView *myPickerView; NSArray *pickerArray; } @end
-(void)addPickerView { pickerArray = [[NSArray alloc]initWithObjects:@"Chess", @"Cricket",@"Football",@"Tennis",@"Volleyball", nil]; myTextField = [[UITextField alloc]initWithFrame: CGRectMake(10, 100, 300, 30)]; myTextField.borderStyle = UITextBorderStyleRoundedRect; myTextField.textAlignment = UITextAlignmentCenter; myTextField.delegate = self; [self.view addSubview:myTextField]; [myTextField setPlaceholder:@"Pick a Sport"]; myPickerView = [[UIPickerView alloc]init]; myPickerView.dataSource = self; myPickerView.delegate = self; myPickerView.showsSelectionIndicator = YES; UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(done:)]; UIToolbar *toolBar = [[UIToolbar alloc]initWithFrame: CGRectMake(0, self.view.frame.size.height- myDatePicker.frame.size.height-50, 320, 50)]; [toolBar setBarStyle:UIBarStyleBlackOpaque]; NSArray *toolbarItems = [NSArray arrayWithObjects: doneButton, nil]; [toolBar setItems:toolbarItems]; myTextField.inputView = myPickerView; myTextField.inputAccessoryView = toolBar; }
如下所示实现委托-
链接:https://www.learnfk.comhttps://www.learnfk.com/ios/ios-ui-elements-picker.html
来源:LearnFk无涯教程网
#pragma mark - Text field delegates -(void)textFieldDidBeginEditing:(UITextField *)textField { if ([textField.text isEqualToString:@""]) { [self dateChanged:nil]; } } #pragma mark - Picker View Data source -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 1; } -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { return [pickerArray count]; } #pragma mark- Picker View Delegate -(void)pickerView:(UIPickerView *)pickerView didSelectRow: (NSInteger)row inComponent:(NSInteger)component { [myTextField setText:[pickerArray objectAtIndex:row]]; } - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow: (NSInteger)row forComponent:(NSInteger)component { return [pickerArray objectAtIndex:row]; }
如下更新 ViewController.m 中的 viewDidLoad -
(void)viewDidLoad { [super viewDidLoad]; [self addPickerView]; }
运行应用程序时,将获得以下输出-
选择文本字段后,将显示Picker视图,如下所示,无涯教程可以选择以下选项:
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