我正在使用UIPickerView来显示随机数.用户可以按下按钮,从而触发随机选择UIPickerView内的数字.
当我调用方法时,UIPickerView中显示的对象或数字有多少并不重要：
- [self.picker selectRow:randomRow inComponent:0 animated:YES];
它总是以相同的时间间隔进行动画处理.
我试过把它放在一个动画块中：
- [UIView beginAnimations:@"identifier" context:nil];
- // code
- [UIView commitAnimations];
但这似乎是一个死路一条.
我也尝试在完成块中执行它：
- // 0.34f is the approximate defualt apple animation
- [UIView animateWithDuration:0.34f animations:^{
- [self.picker selectRow:randomRow inComponent:0 animated:YES];
- } completion:^(BOOL finished) {
- [UIView animateWithDuration:0.34f animations:^{
- [self.picker selectRow:randomRow inComponent:0 animated:YES];
- } completion:nil];
- }];
任何帮助,将不胜感激.
解决方法
我做了一个项目并玩了一段时间,直到找到这个棘手的解决方案.它基于performSelector方法：afterDelay
以下是按钮的内部代码：
- - (void)click:(id)sender
- {
- int randomRow = <>;//Your random method
- int currentRow = [_picker selectedRowInComponent:0];
- int i = 0;
- while(1)
- {
- i++;
- NSString *rowToSelectString = [NSString stringWithFormat:@"%d",currentRow];
- NSDictionary *rowToSelectDictionary = @{@"row":rowToSelectString};
- if(randomRow < currentRow)
- {
- // Go backward
- currentRow--;
- }
- else
- {
- // Go forward
- currentRow++;
- }
- [self performSelector:@selector(selectRowInPicker:) withObject:rowToSelectDictionary afterDelay:i*0.1];//Change the delay as you want
- if(currentRow == randomRow)
- {
- break;
- }
- }
- }
诀窍：
- -(void)selectRowInPicker:(NSDictionary *)rowToSelectDictionary
- {
- NSInteger row = [[rowToSelectDictionary objectForKey:@"row"] integerValue];
- [_picker selectRow:row inComponent:0 animated:YES];
- }
这对我很有用.告诉我你是否遇到问题.
