iphone - 当 selectRow 动画完成时，如何从 UIPickerView 获取回调？

Question

我有一个 UIPickerView，我希望在 selectRow 动画完成时收到通知。

我在 View Controller 中尝试了以下方法，该方法引用了 UIPickerView 但不起作用:

-(void)viewDidLoad
{
    ...
    [UIPickerView setAnimationDelegate:self];
    [UIPickerView setAnimationDidStopSelector:@selector(animationFin ished:finished:context];
    ...
}

- (void)animationFinishedNSString *)animationID finishedBOOL)finished contextvoid *)context
{
    if (finished) {

    }

}

然后在我的代码中的某个位置启动动画:

[picker selectRow:random() % pickerDataCount inComponent:0 animated:YES];

Answer 1

您需要将方法调用嵌套到 beginAnimations/commitAnimation block 中。

- (void) animationFinished:(NSString *)animationID finished:(BOOL)finished context:(void *)context {
    NSLog(@"Here I am");
}


- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{

    [UIView beginAnimations:@"1" context:nil]; // nil = dummy
    [UIPickerView setAnimationDelegate:self];
    [UIPickerView setAnimationDidStopSelector:@selector(animationFinished:finished:context:)];
    [myPickerView selectRow:0 inComponent:0 animated:YES]; // jump with any swipe in picker always to row=0 as dummy to initiate animation
    [UIView commitAnimations];

    //...whatever comes in addition...
}