如何给这个select器视图一个数据源

在这里，我正在编程添加一个pickerview

- (void)viewDidLoad { [super viewDidLoad]; CGRect pickerFrame = CGRectMake(0,280,321,200); UIPickerView *myPickerView = [[UIPickerView alloc] init]; //Not sure if this is the proper allocation/initialization procedure //Set up the picker view as you need it //Set up the display frame myPickerView.frame = pickerFrame; //I recommend using IB just to get the proper width/height dimensions //Add the picker to the view [self.view addSubview:myPickerView]; } 

但是现在我需要实际上有显示内容，并以某种方式发现它何时发生变化以及它已经改变了什么价值。 我该怎么做呢？

Answer 1

在.h文件中放置此代码

 @interface RootVC : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource> 

将数据源和委托分配给select器

 // this view controller is the data source and delegate myPickerView.delegate = self; myPickerView.dataSource = self; 

使用下面的委托和datasouce方法

 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { } - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component { return 200; } - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component { return 50; } - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { NSString *returnStr = @""; if (pickerView == myPickerView) { returnStr = [[levelPickerViewArray objectAtIndex:row] objectForKey:@"nodeContent"]; } return returnStr; } - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { if (pickerView == myPickerView) { return [levelPickerViewArray count]; } } - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 1; } 

Answer 2

您需要创build一个实现UIPickerViewDataSource协议的类，并将其实例分配给myPickerView.dataSource 。