UIPickerView無法解釋的警告

Question

我在應用程序中實現了一個簡單的UIPickerView，並且不斷收到警告，提示我無法解釋未完成的實現和“協議中的方法未完成”。 我列舉了很多例子，但無法弄清我想念的是什么。

這是我的代碼：

。H

@interface ViewTestViewController : UIViewController <UITableViewDelegate, UITableViewDataSource, UIPageViewControllerDataSource, UIPageViewControllerDataSource> {

 UIPickerView *pickerView;
NSMutableArray *pickerList;

....

}
@property (nonatomic, retain) IBOutlet UIPickerView *pickerView;
@property (nonatomic, retain) NSMutableArray *pickerList;


@end

.m

- (void)viewDidLoad
{
[super viewDidLoad];

 …

//PICKER AREA
pickerList = [[NSMutableArray alloc] init];
[pickerList addObject:@"aaa"];
[pickerList addObject:@"bbb"];

CGRect pickerFrame = CGRectMake(0, 200, 0, 0);
pickerView = [[UIPickerView alloc] initWithFrame:pickerFrame];
pickerView.showsSelectionIndicator = YES;    

}

-(IBAction)showPicker:(id)sender {

 [self.view addSubview:pickerView];

}

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView
{
return 1;
}

-(NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component
 {
return [pickerList count];
}

-(NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return [pickerList objectAtIndex:row];
}

-(void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
NSLog(@"Selected item: %@ index of selected item: %i", [pickerList objectAtIndex:row], row);
}

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{

return 200;
}

Answer 1

您需要遵循.h中的UIPickerViewDelegate和UIPickerViewDataSource ，就像您對UITableViewDelegate，UITableViewDataSource等所做的一樣（當前不是）

@interface ViewTestViewController : UIViewController <UIPickerViewDataSource, UIPickerViewDelegate, UITableViewDelegate, UITableViewDataSource, UIPageViewControllerDataSource, UIPageViewControllerDataSource> {

另外，請確保在創建self將其設置為選擇器視圖委托和數據源：

//PICKER AREA
pickerList = [[NSMutableArray alloc] init];
[pickerList addObject:@"aaa"];
[pickerList addObject:@"bbb"];

CGRect pickerFrame = CGRectMake(0, 200, 0, 0);
pickerView = [[UIPickerView alloc] initWithFrame:pickerFrame];
pickerView.showsSelectionIndicator = YES; 
pickerView.dataSource = self;
pickerView.delegate = self;

Answer 2

在您的.h文件中，您聲明自己符合以下協議：

<UITableViewDelegate, UITableViewDataSource, UIPageViewControllerDataSource, UIPageViewControllerDataSource>

這些協議中的每一個都涉及您必須實現的某些方法（有關詳細信息，請參見每個協議的文檔）。 如果未實現所有必需的方法，則會收到此警告。