ios - 具有大量数值的 PickerView

Question

我见过这样使用选择器 View 的示例，其中选择器的值被硬编码到源代码中

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    NSString * title = nil;
 switch(row) {
            case 0:
                title = @"a";
                break;
            case 1:
                title = @"b";
                break;
            case 2:
                title = @"c";
                break;
        }

但是，如果您要在选择器 View 中有 100 个数字，那将是非常不切实际的。我相信您可以在下面看到我正在尝试做的事情。它给我错误

expression is not an integer constant expression

如何在选择器 View 中获取从 0 到 100 的数字？如果有更好的方式让用户选择 1 到 100 之间的数字来输入，欢迎发表评论。

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    NSString * title = nil;

    if (pickerView.tag == 1) // this is otherPickerview
    {
        otherpickerview
        for (int i = 2; i < 100; i++){
            switch(row) {
                case i:
                    title = [NSString stringWithFormat:@"%d", i];
                    break;

            }


        }

    }

Answer 1

让我们试试:

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 3;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return _arr.count;
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
// you can switch to other UIPickerView, and return title for row which you want.
// don't need to loop whenever titleForRow is called.
return _arr[row];
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self.navigationController setNavigationBarHidden:YES];

_arr = [[NSMutableArray alloc]init];
for (int i = 0; i<100; i++) {
    NSString *str = [NSString stringWithFormat:@"%d",i];
    [_arr addObject:str];
}
_pickerView.dataSource = self;
_pickerView.delegate = self;
}