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.
